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1.
Environ Geochem Health ; 42(9): 2645-2653, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32020376

ABSTRACT

Chronic kidney disease of unknown aetiology (CKDu), which is widespread in the North Central Province (NCP) of Sri Lanka, is not associated with commonly known factors such as diabetes, hypertension, and glomerulonephritis. The pathogenicity of CKDu is not well understood, but people with a low body mass index (BMI) and mineral and nutrient deficiencies are more vulnerable to develop CKDu. To understand this situation, the relationship between BMI and the estimated glomerular filtration rate (eGFR) was investigated in people with CKDu in comparison with unaffected age-matched control groups in disease-endemic areas of the NCP. This community-based cross-sectional study was performed in Medirigiriya in the Polonnaruwa district of Sri Lanka, which has one of the highest densities of patients with CKDu. The data for identifying demographic factors and the relationship between CKDu and BMI were investigated by using a validated survey questionnaire. Findings indicated that the group with the highest number of people affected with CKDu (i.e. eGFR of less than 60 mL/min/1.73 m2) had the lowest BMI compared to those with normal eGFR. The majority affected were male farmers. The severity of the disease was inversely associated with BMI values and had a higher prevalence of smoking and alcohol consumption. In addition, those who consume water from household dug wells had significantly lower eGFR (p < 0.0001). A linear regression analysis revealed a significant positive association between lower eGFR and lower BMI (p < 0.001). We hypothesised that the low BMI in those with CKDu may have increased susceptibility to develop CKDu, in the presence of exposure to multiple nephrotoxins and adverse conditions.


Subject(s)
Body Mass Index , Glomerular Filtration Rate , Renal Insufficiency, Chronic/etiology , Adult , Alcohol Drinking/epidemiology , Cross-Sectional Studies , Farmers , Female , Humans , Male , Middle Aged , Minerals , Prevalence , Regression Analysis , Renal Insufficiency, Chronic/epidemiology , Renal Insufficiency, Chronic/physiopathology , Smoking/epidemiology , Sri Lanka/epidemiology , Water Wells
2.
J Steroid Biochem Mol Biol ; 180: 41-50, 2018 06.
Article in English | MEDLINE | ID: mdl-29262380

ABSTRACT

Pregnancy places exceptional demands on vitamin D and calcium availability; thus, their deficiencies during pregnancy threaten the woman and her fetus. Globally, vitamin D and other micronutrient deficiencies are common during pregnancy, especially in developing countries where pregnant women have less access to nutritional supplements. Vitamin D deficiency has been reported to be as high as 40% among pregnant women. As a pregnancy progresses, the requirements for vitamin D increase and thus, can worsen preexisting hypovitaminosis D. Consequently, hypovitaminosis D is increasingly associated with a higher incidence of fetal miscarriage, preeclampsia, gestational diabetes, bacterial vaginosis, and impaired fetal and childhood growth and development. This review explores the recent advances in the understanding of vitamin D and the pivotal role it plays in human reproduction, with an emphasis on pregnancy and its outcomes. Given the seriousness of the issue, there is a pressing need for clinicians to become aware of the risks associated with not identifying and correcting vitamin D deficiency. Identifying and correcting vitamin D deficiency, including safe exposure to sunlight, is particularly relevant for those who seek assistance with fertility issues or prenatal counseling, and those in the beginning of their pregnancy. The data point to a significant protective effects of vitamin D during pregnancy when the 25(OH)D serum level exceeds 30 ng/mL before pregnancy and during the first trimester and, sufficient levels are maintained throughout the pregnancy.


Subject(s)
Dietary Supplements , Prenatal Care , Reproduction , Vitamin D Deficiency/prevention & control , Vitamin D/administration & dosage , Vitamins/administration & dosage , Female , Humans , Pregnancy
3.
Biol Reprod ; 71(5): 1739-45, 2004 Nov.
Article in English | MEDLINE | ID: mdl-15286037

ABSTRACT

The present study investigated whether pregnancy and circulatory ovarian hormones increase the sensitivity of the mesenteric artery to calcitonin gene-related peptide (CGRP)-induced relaxation and possible mechanisms involved in this process. Mesenteric arteries from young adult male rats or female rats (during estrous cycle, after ovariectomy, at Day 20 of gestation, or Postpartum Day 2) were isolated, and the responsiveness of the vessels to CGRP was examined with a small vessel myograph. The CGRP (10(-10) to 10(-7) M) produced a concentration-dependent relaxation of norepinephrine-induced contractions in mesenteric arteries of all groups. Arterial relaxation sensitivity to CGRP was significantly (P < 0.05) greater in female rats compared with male rats. Pregnancy increased the sensitivity to CGRP significantly (P < 0.05) compared to ovariectomized and Postpartum Day 2 rats. In pregnant rats, CGRP-receptor antagonist, CGRP(8-37), inhibited the relaxation responses produced by CGRP. The CGRP-induced relaxation was not affected by N(G)-nitro-l-arginine methyl ester (nitric oxide inhibitor, 10(-4) M) but was significantly (P < 0.05) attenuated by an inhibitor of guanylate cyclase (1H-[1 , 2 , 4 ]oxadizaolo[4 , 3 -a]quinoxalin-1-one, 10(-5) M). Relaxation responses of CGRP on mesenteric arteries were blocked (P < 0.05) by a cAMP-dependent protein kinase A inhibitor, Rp-cAMPs (10(-5) M). The CGRP-induced vasorelaxation was significantly (P < 0.05) attenuated by calcium-dependent (tetraethylammonium, 10(-3) M), but not ATP-sensitive (glybenclamide, 10(-5) M), potassium channel blocker. Therefore, the results of the present study suggest that mesenteric vascular sensitivity to CGRP is higher during pregnancy and that cAMP, cGMP, and calcium-dependent potassium channels appear to be involved. Therefore, we propose that CGRP-mediated vasodilation may be important to maintain vascular adaptations during pregnancy.


Subject(s)
Calcitonin Gene-Related Peptide/pharmacology , Gonadal Steroid Hormones/physiology , Mesenteric Arteries/physiology , Pregnancy, Animal/physiology , Vasodilation/drug effects , Aging/physiology , Animals , Calcium/metabolism , Cyclic AMP/metabolism , Cyclic GMP/metabolism , Female , Male , Postpartum Period/physiology , Potassium Channels/metabolism , Pregnancy , Rats , Rats, Sprague-Dawley , Sex Characteristics
4.
Biol Reprod ; 70(6): 1658-63, 2004 Jun.
Article in English | MEDLINE | ID: mdl-14960487

ABSTRACT

The vascular relaxation sensitivity to calcitonin gene-related peptide (CGRP) is enhanced during pregnancy, compared with nonpregnant human and rat uterine arteries. In the rat uterine artery, two types of CGRP receptors have been shown to coexist, CGRP-A receptor, which is a complex of calcitonin receptor-like receptor (CRLR), and receptor activity-modifying protein (RAMP(1)) and CGRP-B receptor, which is different from CRLR. In the present study, we hypothesized that: 1) CGRP-induced vasorelaxation in rat uterine artery is mediated through CGRP-A receptor and 2) N-terminal (Nt) domain of CRLR (Nt-CRLR) has a major contribution in ligand binding and mediating CGRP- induced relaxation effects in rat uterine artery. Polyclonal antibodies against Nt-domain of CRLR and RAMP(1) (Nt-RAMP(1)) were raised in rabbits and characterized for their specificity and were used to inhibit CGRP-induced vasorelaxation in rat uterine artery. For vascular relaxation studies, uterine arteries from Day 18 pregnant rats were isolated, and responsiveness of the vessels to CGRP was examined with a small vessel myograph. CGRP (10(-10) to 10(-7) M) produced a concentration-dependent relaxation of norepinephrine-induced contractions in Day 18 pregnant rat uterine arteries. These effects were significantly (P < 0.05) inhibited when uterine arteries were incubated with the antibody raised against Nt-CRLR (PD(2) = 6.75 +/- 0.20) and were totally abolished in presence of antibodies for both Nt-CRLR and Nt-RAMP(1) (PD(2) = 6.14 +/- 0.35). In contrast, a monoclonal antibody for CGRP-B receptor had no effect on CGRP-induced rat uterine artery relaxation. These studies suggest that CGRP effects in rat uterine artery are mediated through CGRP-A receptor and that Nt-domain of CRLR may play a predominant role in CGRP binding and thus in causing CGRP-induced uterine artery relaxation.


Subject(s)
Calcitonin Gene-Related Peptide/pharmacology , Membrane Proteins/chemistry , Receptors, Calcitonin/chemistry , Uterus/blood supply , Uterus/drug effects , Vasodilation/drug effects , Animals , Antibodies/pharmacology , Antibodies, Monoclonal/pharmacology , Calcitonin Gene-Related Peptide/antagonists & inhibitors , Calcitonin Receptor-Like Protein , Cell Membrane/metabolism , Female , In Vitro Techniques , Intracellular Signaling Peptides and Proteins , Membrane Proteins/antagonists & inhibitors , Membrane Proteins/immunology , Membrane Proteins/metabolism , Pregnancy , Protein Structure, Tertiary , Rats , Rats, Sprague-Dawley , Receptor Activity-Modifying Proteins , Receptors, Calcitonin/antagonists & inhibitors , Receptors, Calcitonin/immunology , Receptors, Calcitonin/metabolism , Vasodilation/physiology
5.
Biol Reprod ; 70(4): 1055-62, 2004 Apr.
Article in English | MEDLINE | ID: mdl-14668209

ABSTRACT

Calcitonin gene-related peptide (CGRP) is a potent vasodilator neuropeptide known to be involved in the regulation of vascular tone. Results of previous studies from our laboratory and others suggest that vascular sensitivity to CGRP is enhanced during pregnancy and that the female sex steroid hormones estradiol-17beta (E2) and progesterone (P4) may be involved in this process. We hypothesized that CGRP receptors in the mesenteric artery are increased during pregnancy and with sex steroid hormone treatments. In the present study, we investigated whether pregnancy and female sex steroid hormones modulate the CGRP-receptors CGRP-A and CGRP-B in the mesenteric artery in the rat. The CGRP-A receptor consists of calcitonin receptor-like receptor (CRLR) and receptor activity-modifying protein 1 (RAMP1); however, the CGRP-B receptor needs to be further characterized. Messenger RNA levels for CRLR and RAMP1 were assessed by reverse transcription-polymerase chain reaction, and CGRP-B receptor proteins levels were determined by Western blot analysis. In addition, [125I]CGRP binding was measured by Scatchard analysis. Both mRNA for CGRP-A (CRLR and RAMP1) and the protein for CGRP-B receptors in mesenteric arteries were increased with pregnancy compared to nonpregnant, diestrous animals. A P4 antagonist, RU-486, downregulated and P4 upregulated these receptors in mesenteric arteries (P < 0.05) in pregnant rats. In adult ovariectomized rats, P4 upregulated CRLR and RAMP1 mRNA levels as well as [125I]CGRP-binding sites. The CGRP-B-receptor protein levels were significantly (P < 0.05) elevated by P4 and by combined E2 and P4 treatment. Together with earlier findings, these data suggest that increases in the expression of CGRP-A (CRLR and RAMP1) and CGRP-B receptors in mesenteric arteries may be important in reducing vascular resistance and in vascular adaptations that occur during pregnancy; in addition, P4 may be involved in this process.


Subject(s)
Aorta/metabolism , Estradiol/pharmacology , Mesenteric Arteries/metabolism , Pregnancy/metabolism , Progesterone/pharmacology , Receptors, Calcitonin Gene-Related Peptide/metabolism , Animals , Aorta/drug effects , Calcitonin Gene-Related Peptide/metabolism , Calcitonin Receptor-Like Protein , Down-Regulation , Drug Combinations , Female , Hormone Antagonists/pharmacology , Intracellular Signaling Peptides and Proteins , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mesenteric Arteries/drug effects , Mifepristone/pharmacology , Osmolar Concentration , Ovariectomy , Protein Isoforms/metabolism , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Receptor Activity-Modifying Protein 1 , Receptor Activity-Modifying Proteins , Receptors, Calcitonin/genetics , Receptors, Calcitonin/metabolism , Up-Regulation
6.
Biol Reprod ; 69(5): 1635-41, 2003 Nov.
Article in English | MEDLINE | ID: mdl-12855600

ABSTRACT

Human and rodent studies have demonstrated that calcitonin gene-related peptide (CGRP), a potent vasodilator, relaxes uterine tissue during pregnancy but not during labor. The vascular sensitivity to CGRP is enhanced during pregnancy, compared to nonpregnant human uterine arteries. In the present study, we hypothesized that uterine artery relaxation effects of CGRP are enhanced in pregnant rats compared to nonpregnant diestrus rats (NP-DE) and that several secondary messenger systems are involved in this process. We also hypothesized that the expression of CGRP-A receptor components, calcitonin receptor-like receptor (CRLR), receptor activity-modifying protein (RAMP1), and CGRP-B receptors are greater in pregnant rats. For vascular relaxation studies, uterine arteries from either NP-DE or Day 18 pregnant rats were isolated, and responsiveness of the vessels to CGRP was examined with a small vessel myograph. CGRP-A and CGRP-B receptor expressions were assessed by RT-PCR and Western immunoblotting, respectively. CGRP (10(-10)--10(-7) M) produced a concentration-dependent relaxation of norepinephrine-induced contractions in both NP-DE and Day 18 pregnant rat uterine arteries. Pregnancy increased the vasodilator sensitivity to CGRP significantly (P < 0.05) compared to NP-DE rats. CGRP receptor antagonist, CGRP8-37, inhibited CGRP-induced relaxation of pregnant uterine arteries. The CGRP-induced relaxation was not affected by NG-nitro-l-arginine methyl ester (L-NAME) (nitric oxide inhibitor, 10(-4) M) but was significantly (P < 0.05) attenuated by inhibitors of guanylate cyclase (ODQ, 10(-5) M) and adenylate cyclase (SQ 22536, 10(-5) M). CGRP-induced vasorelaxation was significantly (P < 0.05) attenuated by potassium channel blockers KATP (glybenclamide, 10(-5) M) and K(CA) (tetraethylammonium, 10(-3) M). The expression of CRLR and RAMP1 was significantly (P < 0.05) elevated during pregnancy compared to nonpregnant diestrus state (NP-DE). However, CGRP-B receptor proteins in uterine arteries were not altered with pregnancy compared to those of NP-DE. These studies suggest that CGRP-induced increases in uterine artery relaxation may play a role in regulating blood flow to the uterus during pregnancy and, therefore, in fetal growth and survival.


Subject(s)
Calcitonin Gene-Related Peptide/pharmacology , Muscle, Smooth, Vascular/drug effects , Pregnancy, Animal/physiology , Uterus/blood supply , Adenylyl Cyclase Inhibitors , Animals , Arteries/drug effects , Blotting, Western , Enzyme Inhibitors/pharmacology , Female , Guanylate Cyclase/antagonists & inhibitors , In Vitro Techniques , Intracellular Signaling Peptides and Proteins , Membrane Proteins/biosynthesis , Muscle Relaxation/drug effects , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide Synthase/antagonists & inhibitors , Ornithine Decarboxylase Inhibitors , Peptide Fragments/pharmacology , Pregnancy , Pregnancy, Animal/metabolism , RNA, Messenger/biosynthesis , Rats , Rats, Sprague-Dawley , Receptor Activity-Modifying Protein 1 , Receptor Activity-Modifying Proteins , Receptors, Calcitonin Gene-Related Peptide/biosynthesis , Receptors, Calcitonin Gene-Related Peptide/drug effects
7.
Cell Tissue Res ; 311(3): 383-91, 2003 Mar.
Article in English | MEDLINE | ID: mdl-12658446

ABSTRACT

The distribution of the tachykinin receptors neurokinin-1 (NK1), neurokinin-2 (NK2) and neurokinin-3 (NK3), and the calcitonin gene-related peptide-1 (CGRP1) receptor were examined in rat teeth and tooth-supporting tissues by immunohistochemical methods and light and confocal microscopy. Western blot analysis was performed to identify the NK1- and the CGRP1-receptor proteins in the dental pulp. The results showed that odontoblasts and ameloblasts, cementoblasts and cementocytes, osteoblasts and osteocytes are all supported with the tachykinin receptors NK1 and NK2, but a distinct, graded cellular labeling pattern was demonstrated. The ameloblasts were also positive for CGRP1 receptor. Blood vessels in oral tissues expressed the tachykinin receptors NK1, NK2 and NK3, and the CGRP1 receptor. Both gingival and Malassez epithelium were abundantly supplied by NK2 receptor. Pulpal and periodontal fibroblasts demonstrated NK1 and NK2 receptors. Western blot analysis identified both the NK1- and the CGRP1-receptor proteins in the dental pulp. These results clearly indicate that the neuropeptides substance P, neurokinin A, neurokinin B and CGRP, released from sensory axons upon stimulation, directly modulate the function of the different types of bone and dental hard tissue cells, and regulate functions of blood vessels, fibroblasts and epithelial cells in oral tissues.


Subject(s)
Jaw/innervation , Receptors, Calcitonin Gene-Related Peptide/metabolism , Receptors, Neurokinin-1/metabolism , Sensory Receptor Cells/metabolism , Tooth/innervation , Animals , Blood Vessels/cytology , Blood Vessels/innervation , Blood Vessels/metabolism , Epithelial Cells/cytology , Epithelial Cells/metabolism , Female , Fibroblasts/cytology , Fibroblasts/metabolism , Gingiva/cytology , Gingiva/innervation , Gingiva/metabolism , Immunohistochemistry , Jaw/cytology , Jaw/metabolism , Mouth Mucosa/cytology , Mouth Mucosa/innervation , Mouth Mucosa/metabolism , Neuropeptides/metabolism , Rats , Rats, Wistar , Sensory Receptor Cells/cytology , Tooth/cytology , Tooth/metabolism
8.
Biol Reprod ; 67(6): 1881-7, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12444066

ABSTRACT

The aim of the present study is to investigate whether vascular protective effects of steroid hormones in aged female rats are mediated through calcitonin gene-related peptide (CGRP), a known potent vasodilator. This rat model reflects the postmenopausal state in humans. We examined whether blood pressure lowering effects of CGRP are enhanced in aged female rats when steroid hormone treatments are administered. We observed that 1) continuous infusion of CGRP lowered blood pressures in rats treated with estradiol-17beta and progesterone (P < 0.05), 2) acute hypotensive effects of CGRP were significantly (P < 0.05) greater in the presence of steroid hormones than in vehicle-treated groups, 3) blood pressure decreases in response to CGRP are lower in aged female rats than they are in young adult ovariectomized rats, and 4) age-related differences in the hypotensive effects of CGRP were nullified when animals were treated with steroid hormones. These data suggest that female sex steroid hormones may modulate arterial blood pressure by regulating the CGRP effector system in female rats regardless of age.


Subject(s)
Aging , Blood Pressure/drug effects , Calcitonin Gene-Related Peptide/pharmacology , Estradiol/pharmacology , Progesterone/pharmacology , Animals , Antihypertensive Agents/pharmacology , Calcitonin Gene-Related Peptide/administration & dosage , Drug Interactions , Female , Ovariectomy , Rats
9.
Biol Reprod ; 67(5): 1430-4, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12390872

ABSTRACT

Calcitonin gene-related peptide (CGRP) levels in plasma and the dorsal root ganglia (DRG) are increased during pregnancy and in ovariectomized rats injected with ovarian hormones. Vasodilatory responses to CGRP are also increased in these animals. In the present study, we hypothesized that pregnancy and ovarian hormones elevate the contents of CGRP in perivascular nerves. We assessed CGRP-dependent mesenteric vascular relaxation induced by electrical field stimulation (EFS) and arterial content of CGRP. Because the mesenteric artery represents resistance vessels, segments of mesenteric arteries collected from female rats at different stages of the estrous cycle, pregnancy, or postpartum and from male rats were used in this study. The EFS-induced relaxation in the presence and absence of CGRP(8-37), an antagonist of CGRP, was used to measure CGRP-dependent relaxation, and radioimmunoassay (RIA) of tissue homogenates was used to assess changes in CGRP content in mesenteric branch arteries. The results show that CGRP-dependent, EFS-induced relaxation response was lower in female rats at diestrus and proestrus than in male rats, and no statistically significant differences were observed between Gestational Day 20 and Postpartum Day 2. The RIA revealed significantly lower mesenteric artery CGRP levels in female rats at proestrus, gestation, and postpartum than in female rats at diestrus or in male rats. We conclude that no correlation exists between CGRP-dependent, EFS-induced relaxation and CGRP content in the mesenteric arteries of these animal groups. Because both CGRP levels in DRG and serum are reported to be elevated, the reduced CGRP content in the vasculature during pregnancy and proestrus implicate enhanced basal release of CGRP at the nerve terminal in these animals.


Subject(s)
Calcitonin Gene-Related Peptide/metabolism , Mesenteric Arteries/metabolism , Pregnancy/metabolism , Animals , Calcitonin Gene-Related Peptide/analysis , Calcitonin Gene-Related Peptide/pharmacology , Electric Stimulation , Female , Ganglia, Spinal/metabolism , Gonadal Steroid Hormones/physiology , In Vitro Techniques , Male , Mesenteric Arteries/drug effects , Peptide Fragments/pharmacology , Postpartum Period , Radioimmunoassay , Rats , Rats, Sprague-Dawley , Sex Factors , Steroids/physiology , Vascular Resistance/drug effects , Vascular Resistance/physiology , Vasomotor System/drug effects , Vasomotor System/physiology
10.
Biol Reprod ; 67(2): 624-9, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12135906

ABSTRACT

Calcitonin gene-related peptide (CGRP) is the most potent endogenous vasodilatory peptide, and is involved in the regulation of blood flow to vital organs. We have previously shown that CGRP may be involved in vascular adaptations that occur during pregnancy, and that steroid hormones may be involved in these mechanisms. We hypothesized that endogenous CGRP is required for maintaining blood pressure and fetoplacental growth in pregnant rats, and that progesterone will enhance CGRP effects. The vasodilatory effects of CGRP are known to be inhibited by a competitive CGRP receptor antagonist, the C-terminal fragment CGRP(8-37). In the present study, we investigated whether continuous s.c. infusion of CGRP(8-37) to pregnant rats will reduce fetoplacental growth and increase systolic blood pressure. We also assessed whether progesterone will alter the effects of CGRP(8-37) on blood pressure during postpartum. Groups of five pregnant rats were s.c. infused with varying doses of CGRP(8-37) from Day 17 of pregnancy. Daily systolic blood pressures, pup weight, mortality at term delivery, and fetoplacental weights on Day 20 of gestation were measured. CGRP(8-37) at a dose of 0.083 mg day(-1) kg(-1) body weight (BW) showed no effects; however, doses of 0.33 and 1.33 mg day(-1) kg(-1) BW increased (P < 0.05) blood pressure during pregnancy, and these elevated blood pressures persisted during postpartum with the highest dose used. Progesterone (2 mg per injection, twice a day; s.c.) treatment significantly elevated blood pressure in rats infused with CGRP(8-37) during postpartum, suggesting that progesterone regulates CGRP-induced vascular effects. CGRP(8-37) infusion caused significant reductions in pup weight with an increase in mortality rate, and these effects were dose-dependent. Placental and fetal weights were also decreased prior to term on Day 20 of gestation, 72 h after CGRP(8-37) infusion, indicating effects on uteroplacental tissues. Therefore, we suggest that endogenous CGRP plays an important role in maintaining normal fetoplacental development, fetal survival, and vascular adaptations during pregnancy.


Subject(s)
Blood Pressure/drug effects , Calcitonin Gene-Related Peptide Receptor Antagonists , Calcitonin Gene-Related Peptide/pharmacology , Embryonic and Fetal Development/drug effects , Fetal Death/chemically induced , Peptide Fragments/pharmacology , Pregnancy, Animal/physiology , Animals , Birth Weight/drug effects , Dose-Response Relationship, Drug , Female , Fetal Weight/drug effects , Organ Size/drug effects , Placenta/blood supply , Placenta/drug effects , Placentation , Postpartum Period/physiology , Pregnancy , Progesterone/physiology , Rats , Rats, Sprague-Dawley , Regional Blood Flow/drug effects , Regional Blood Flow/physiology
11.
Arch Histol Cytol ; 64(3): 295-303, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11575425

ABSTRACT

Amylin (AMY) is a 37 amino acid peptide of pancreatic origin that has been localized in peripheral and central nervous structures. Both peripheral and central injection of the peptide causes various effects, including anorectic behavior in rats. Prompted by previous reports showing that the anorectic effect of AMY is mediated by histamine release, we immunohistochemically investigated possible relationships between these two systems at the light microscopical level. Monkey (Macaca fuscata japonica) hypothalamus specimens were submitted to immunohistochemical double staining procedures using AMY and histidine decarboxylase (HDC) antisera. AMY-immunoreactive neurons were found widely distributed in several nuclei of the monkey hypothalamus including the supraoptic, paraventricular, perifornical, periventricular, ventromedial, arcuate, and tuberomammillary nuclei. We detected AMY-immunoreactive nerve fibers throughout the hypothalamus, the median eminence and hypothalamus-neurohypophysial tract. Although AMY- and HDC-immunoreactive neuronal cell bodies occupied distinct hypothalamic zones, many HDC-immunoreactive cell bodies and dendrites, particularly those in the periventricular, arcuate, and rostral tuberomammillary regions, were surrounded by numerous AMY-immunoreactive nerve fiber varicosities. These findings demonstrate for the first time the presence of a discrete number of AMY-immunoreactive neurons in the monkey hypothalamus and add morphological support to the experimental data demonstrating that AMY probably exerts its influence on food intake via the histaminergic system.


Subject(s)
Amyloid/metabolism , Histamine/metabolism , Hypothalamus/metabolism , Neurons/metabolism , Animals , Biomarkers , Histidine Decarboxylase/immunology , Humans , Hypothalamus/cytology , Immunoenzyme Techniques , Islet Amyloid Polypeptide , Macaca , Male , Neurons/cytology
12.
Obstet Gynecol ; 97(6): 893-7, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11384692

ABSTRACT

OBJECTIVE: To determine whether circulating levels of calcitonin gene-related peptide (CGRP) and parathyroid hormone-related peptide (PTHrP) are altered in preeclampsia, and to assess the effects of magnesium sulfate therapy on circulating levels of these two peptides. METHODS: The study population included 25 women with preeclampsia and 25 normotensive controls of similar gestational age. The effects of magnesium sulfate therapy were evaluated in 17 of the 25 preeclamptic women. Circulating levels of immunoreactive CGRP and PTHrP, including calcium, magnesium, and phosphate in the maternal and umbilical cord serum were measured. RESULTS: The frequency of preeclampsia subjects with nondetectable PTHrP (under 3 pg/mL) was significantly higher (92% versus 48%, P <.001), whereas maternal serum CGRP levels were significantly lower (50 +/- 19 versus 90 +/- 23 pg/mL, P <.001). Similarly, the frequency of newborns with nondetectable PTHrP levels in umbilical serum was significantly higher (68% versus 36%, P <.05), whereas the levels of CGRP were significantly lower (67 +/- 17 versus 79 +/- 16 pg/mL, P <.05). Magnesium sulfate treatment resulted in a significant increase in maternal circulating CGRP levels (64 +/- 17 versus 47 +/- 18 pg/mL, P <.05) with no changes in PTHrP. CONCLUSION: Maternal circulating PTHrP and CGRP concentrations were significantly lower in women with preeclampsia, which may contribute to the development and maintenance of hypertension during pregnancy. Furthermore, magnesium sulfate therapy increased the levels of CGRP in the maternal circulation.


Subject(s)
Calcitonin Gene-Related Peptide/blood , Magnesium Sulfate/administration & dosage , Pre-Eclampsia/blood , Pre-Eclampsia/drug therapy , Pregnancy Outcome , Proteins/analysis , Adult , Chi-Square Distribution , Female , Fetal Blood/chemistry , Humans , Parathyroid Hormone-Related Protein , Pre-Eclampsia/diagnosis , Pregnancy/blood , Probability , Reference Values , Statistics, Nonparametric , Treatment Outcome
13.
Biol Reprod ; 64(6): 1776-83, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11369608

ABSTRACT

Calcitonin gene-related peptide (CGRP) is a potent vasodilator neuropeptide known to be involved in the regulation of vascular resistance. Several lines of evidence suggest that CGRP plays a role in the vascular adaptations that occur during normal pregnancy; however, the effects of exogenous CGRP on systemic and regional hemodynamics during pregnancy remain unknown. Therefore, the purpose of this study was to determine the hemodynamic effects of systemically administered CGRP in adult pregnant (Day 19) and ovariectomized (ovx) rats using the radioactive microsphere technique. In addition, we also used ovariectomized rats treated for 3 days with estradiol (E2), progesterone (P4), E2 + P4 in sesame oil, or oil only to assess if these hormones regulate the CGRP-induced hemodynamic changes. On the day of study, catheters were inserted into the left cardiac ventricle (through the right carotid artery), right jugular vein, and caudal tail artery. Hemodynamic studies using radioactive microspheres were then performed in conscious rats 3 h after recovery from anesthesia. Blood pressure and heart rate were continuously monitored, and left ventricular pressure was determined immediately prior to each microsphere injection. Microspheres labeled with either (141)Ce or (85)Sr were injected prior to and 2 min following the i.v. bolus injection of CGRP (270 pmol/kg body weight [BW]). Mean arterial pressure (MAP) and total vascular resistance in pregnant rats was lower than in ovx rats, and this was further decreased with an i.v. bolus injection of 270 pmol CGRP/kg BW. Cardiac output was elevated with further increases upon CGRP administration in pregnant but not in ovx rats. The CGRP-induced changes in MAP, total vascular resistance, and cardiac output in E2 + P4 -treated rats were similar to that observed in Day 19 pregnant rats, indicating that CGRP effects on these parameters during pregnancy may be modulated by steroid hormones. Both pregnancy and E2 + P4 treatment in ovx rats caused significant decreases in CGRP-induced resistance in mesenteric, coronary, and renal vasculature. Thus, the vasodilatory sensitivity to CGRP during pregnancy may be mediated through decreased total vascular resistance, particularly to coronary, mesenteric, and renal vascular beds. Thus, CGRP-induced vasodilatory effects may play a role in mediating vascular adaptations that occur during pregnancy and that steroid hormones may modulate these CGRP effects.


Subject(s)
Calcitonin Gene-Related Peptide/pharmacology , Estradiol/pharmacology , Hemodynamics/drug effects , Progesterone/pharmacology , Animals , Blood Flow Velocity , Blood Pressure/drug effects , Brain/blood supply , Cardiac Output/drug effects , Cervix Uteri/blood supply , Colon/blood supply , Female , Heart Rate/drug effects , Intestines/blood supply , Kidney/blood supply , Microspheres , Ovariectomy , Pregnancy , Rats , Uterus/blood supply , Vascular Resistance/drug effects
14.
Pain ; 89(2-3): 265-73, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11166483

ABSTRACT

Peripheral inflammation induced with a knee joint injection of a mixture of kaolin/carrageenan (k/c) produces primary and secondary hyperalgesia. Inflammatory pain is thought to involve a variety of transmitters released from nerve terminals, including amino acids, substance P (SP) and calcitonin gene-related peptide (CGRP). In the present study, mice deficient in the calcitonin/alpha CGRP gene (CGRP(-/-)) displayed normal responses to noxious stimuli. However, the CGRP knockout mice failed to demonstrate development of secondary hyperalgesia after induction of knee joint inflammation in two tests that assess central sensitization, through testing at sites remote from the primary insult. Nociceptive behavioral responses were assessed using the hot-plate test and paw withdrawal latency (PWL) to radiant heat applied to the hindpaw. The CGRP(-/-) mice showed no signs of secondary hyperalgesia after development of knee joint inflammation, while the expected significant decrease in the PWL was observed in the CGRP(+/+) mice as control. The CGRP(-/-) mice also had a prolonged rather than a shortened response latency in the hot-plate test 4 h after knee joint injection of k/c. Immunohistological study showed that CGRP-like immunoreactivity (CGRP-LI) was absent in the spinal cord and dorsal root ganglia taken from the CGRP(-/-) mice. These results indicate that endogenous CGRP plays an important role in the plastic neurogenic changes occurring in response to peripheral inflammatory events including the development of nociceptive behaviors.


Subject(s)
Arthritis/genetics , Arthritis/physiopathology , Calcitonin Gene-Related Peptide/genetics , Calcitonin/genetics , Nociceptors/physiology , Animals , Arthritis/pathology , Behavior, Animal/physiology , Hot Temperature , Immunohistochemistry , Joints/pathology , Mice , Mice, Knockout , Pain Measurement , Reaction Time
15.
J Bone Miner Res ; 15(11): 2240-4, 2000 Nov.
Article in English | MEDLINE | ID: mdl-11092405

ABSTRACT

Nitric oxide (NO) is known to affect bone metabolism. Previous animal studies have shown that NO donor therapy can prevent ovariectomy (OVX)-induced as well as corticosteroid-induced bone loss. Therefore, we have carried out a 1-year human, randomized, controlled pilot clinical study to assess the efficacy of nitroglycerin (NG) in the prevention of estrogen-deficiency-induced bone loss in women. We observed that NG ointment, when applied to the skin once a day (within 4 weeks of undergoing oophorectomy), mimicked estrogen replacement therapy in prevention of bone loss. The primary outcome of bone mineral density (BMD) was not different in the two groups at the end of 1 year. Urinary N-telopeptide levels were significantly decreased after administration of either estrogen or NG. Although estrogen decreased serum osteocalcin and bone-specific alkaline phosphatase levels, NG therapy significantly increased these two markers of bone formation. Further, it was revealed that for up to 1 year, these doses of NG did not result in tachyphylaxis. This study showed for the first time that NG is as effective as estrogen in preventing bone loss in these surgically induced menopausal women. Additionally, the dose of NG used in this study was three to four times less than that generally used to affect cardiovascular homeostasis. Although in this randomized clinical study only a small number of patients was examined, data are encouraging. If these data hold true in large randomized, controlled clinical trials, then NG could emerge as an efficacious, cost-effective, affordable, safe, and convenient form of therapy (especially as an alternative therapy to hormone-replacement therapy [HRT]) for prevention of postmenopausal bone loss.


Subject(s)
Bone Resorption/prevention & control , Estrogen Replacement Therapy , Estrogens, Conjugated (USP)/pharmacology , Nitroglycerin/pharmacology , Ovariectomy/adverse effects , Adult , Alkaline Phosphatase/blood , Biomarkers/blood , Biomarkers/urine , Bone Density/drug effects , Collagen/urine , Collagen Type I , Female , Humans , Middle Aged , Osteocalcin/blood , Peptides/urine , Pilot Projects , Treatment Outcome
16.
Peptides ; 21(11): 1743-9, 2000 Nov.
Article in English | MEDLINE | ID: mdl-11090930

ABSTRACT

Immunohistochemical studies were conducted on rat brainstem using a specific polyclonal antiserum against the COOH-terminal (25-37) of human amylin. Amylin-immunoreactive cell bodies were observed in the vestibular, cochlear, trapezoid, and inner cerebellar nuclei and in the mesencephalic nucleus of trigeminal nerve. Positive cell bodies were also found in lateral, gigantocellular and magnocellular reticular nuclei. Numerous amylin-immunoreactive nerve fibers were shown in the trigeminal spinal tract, in the solitary area and in the area postrema. Amylin-immunoreactive cell bodies were often surrounded by a network of tyrosine hydroxylase-immunoreactive nerve fibers. These results provide morphologic evidence that amylin may play a role in some discrete sensory functions.


Subject(s)
Amyloid/biosynthesis , Brain Stem/metabolism , Animals , Cerebellar Nuclei/metabolism , Cerebellum/metabolism , Humans , Immunohistochemistry , Islet Amyloid Polypeptide , Male , Medulla Oblongata/metabolism , Nerve Fibers/metabolism , Pons/metabolism , Rats , Rats, Wistar , Trigeminal Nerve/metabolism , Tyrosine 3-Monooxygenase/metabolism
17.
Neuroscience ; 100(2): 381-91, 2000.
Article in English | MEDLINE | ID: mdl-11008176

ABSTRACT

Quantitative autoradiography (using [125I]human alpha-calcitonin gene-related peptide as a ligand) and immunofluorescence (using monoclonal antibodies directed against a purified receptor) followed by confocal analysis were applied to analyse the distribution and cellular localization of the calcitonin gene-related peptide receptor in the rat cerebellum during development. From late embryonic days to the end of the second postnatal week, during the time window of calcitonin gene-related peptide expression in climbing fibers, high levels of calcitonin gene-related peptide binding sites were found in the white matter, where immunolabeling was present in oligodendrocytes. Lower levels were found in the cerebellar cortex, where receptor immunolabeling was found in Bergmann glia in a presumptive cell surface location and, during the second postnatal week, also in the cytoplasm of Purkinje cells. From the end of the second postnatal week to adulthood, when calcitonin gene-related peptide is no longer present in climbing fibers, the number of calcitonin gene-related peptide binding sites increased in the molecular layer, where not only Bergmann glia but also Purkinje cell distal dendritic branchlets were immunolabeled in a presumptive cell surface location. Concomitantly, the number of calcitonin gene-related peptide binding sites sharply decreased in the white matter. The developmental expression of the calcitonin gene-related peptide receptor and the previously described proliferating/differentiating effects of the peptide on glial cells suggest that calcitonin gene-related peptide and its receptor may promote a coordinated development of cerebellar glial cells, an effect driven mainly by the calcitonin gene-related peptide released by climbing fibers. As a result of glia-neuron interactions, an indirect effect on the differentiation of the cerebellar neuronal circuitry is also likely to occur.


Subject(s)
Calcitonin Gene-Related Peptide/metabolism , Cerebellum/metabolism , Neuroglia/metabolism , Neurons/metabolism , Animals , Animals, Newborn , Autoradiography , Cerebellum/growth & development , Humans , Immunohistochemistry , Rats , Rats, Sprague-Dawley
18.
J Bone Miner Res ; 15(6): 1119-25, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10841180

ABSTRACT

Recently, we showed that supplementation with nitric oxide (NO) via donor nitroglycerin (NG) alleviated the ovariectomy and corticosteroid-induced bone loss in rats. In humans, high doses or frequent applications of NG (i.e., for angina) lead to rapid loss of its efficacy in relieving angina. To examine whether there is a similar effect on the loss of efficacy of NG on bone, we examined the frequency-dependent effects of NG on bone mineral density (BMD), bone mass, trabecular bone volumes (BV/TV), and blood pressure in rats. Thirty 7-month-old female Brown Norway rats underwent ovariectomy, and an additional six rats were sham-operated. The ovariectomized rats were treated either with vehicle (ovariectomized control), 17beta-estradiol (E2; positive control), or 0.2 mg NG (via dermal application) once, twice, or three times a day. Before and at the end of the 10-week treatment period, BMD of the lumbar spine was measured by dual-energy X-ray absorptiometric (DXA) scanning and expressed as a percentage change. BMD in ovariectomized rats was significantly lower (-2.5 +/- 2.0%) compared with the sham-operated rats (+6.3 +/- 5.3%; p < 0.01). Estrogen therapy completely abolished the ovariectomy-induced potential bone loss (+5.9 +/- 3.4%). Application of NG once daily also completely prevented (+6.2 +/- 2.8%; p < 0.01) the ovariectomy-induced bone loss (i.e., it was as effective as estrogen). However, the beneficial effects of NG on BMD were significantly reduced with increased frequency of application of NG (+1.9 +/- 2.1%, twice a day and -0.2 +/- 3.3% three times a day). Estrogen or once daily administration of NG preserved femur weights, BV/TV, and decreased urinary deoxypyridinoline levels as expected. However, a higher level of serum osteocalcin and bone-specific alkaline phosphatase levels were maintained only with once daily administration of NG. There were no adverse effects of these doses of NG on blood pressure, but a tendency to lower blood pressure was noticed with increased frequency of NG. These results confirmed our previous findings that NO donors counteract the bone loss associated with estrogen deficiency. However, these beneficial effects of maintaining BMD are lost with increased frequency of NG application.


Subject(s)
Bone and Bones/drug effects , Nitric Oxide Donors/pharmacology , Nitric Oxide , Nitroglycerin/pharmacology , Animals , Body Weight/drug effects , Bone Density/drug effects , Bone and Bones/physiology , Female , Nitroglycerin/administration & dosage , Organ Size/drug effects , Rats , Rats, Inbred BN , Uterus/drug effects
19.
J Clin Densitom ; 3(2): 187-201, 2000.
Article in English | MEDLINE | ID: mdl-10871912

ABSTRACT

Osteoporosis is a debilitating disease characterized by decreased bone mineral density (BMD) leading to fractures. It primarily affects postmenopausal women and elderly men. Prevention of osteoporosis is very important because present therapies do not have the potential to mend damage to the bone microarchitecture caused by osteoporosis. The first line of prevention and treatment of osteoporosis is hormone replacement therapy (HRT). All of the approved drugs for the prevention and treatment of osteoporosis act as inhibitors of bone resorption; these drugs include HRT, selective estrogen receptor modulators, calcitonin, and bisphosphonates. The latter two drugs have also been shown to prevent fractures. This article discusses data from nine controlled prospective clinical studies. Study 1 was designed to assess the efficacy of combined HRT and bisphosphonate in preventing osteoporosis during the early stages of menopause. This combined therapy increased the lumbar spine BMD by 10.9% and femoral BMD by 7.3% over 4 yr, compared with 6.8 and 4.0% with HRT alone, and 6.8 and 1.2% with bisphosphonate alone. Study 2 was conducted on postmenopausal women with established osteoporosis. These results showed a 10.4 and 7.0% increase in BMD in vertebrae and femora, respectively, compared with 7.3 and 4.8% increases in the HRT group, and 6.8 and 0.9% in the bisphosphonate group. Data from study 3 demonstrated similar findings in that the combination of alendronate and HRT also enhanced BMD values. Studies 4 and 5 assessed the efficacy of the combined therapy of HRT and calcitonin in the prevention of early postmenopausal bone loss. Both studies demonstrated a significant increase in BMD over and above that observed with either HRT or calcitonin alone. Studies 6, 7, and 8 demonstrated that the addition of testosterone to estrogen therapy further increased BMD when compared to estrogen therapy alone, and also prevented the expected decreases in markers of bone formation in early postmenopausal women. Study 9 demonstrated a synergistic effect on BMD in postmenopausal women, when HRT was coadministered with monofluorophosphate. Other combination therapies may also enhance BMD (e.g., the combination of alendronate and parathyroid hormone [PTH]). However, some agents either lose their efficacy or have no added effects on BMD when they are coadministered (e.g., tiludronate and PTH, calcitonin and PTH, calcitonin and anabolic steroids). These studies illustrate that in a subgroup of patients (i.e., patients with high bone turnover and/or severe osteoporosis), specific combination treatments such as HRT with bis-phosphonates, calcitonin, or androgens (and perhaps also with PTH, fluoride, nitric oxide donors) provide additional beneficial effects over a single-drug therapy. Whether these combination therapies are more effective than individual drugs in reducing fractures still needs to be determined.


Subject(s)
Diphosphonates/therapeutic use , Fluorides/therapeutic use , Hormone Replacement Therapy , Osteoporosis, Postmenopausal/prevention & control , Bone Density/drug effects , Drug Therapy, Combination , Humans , Osteoporosis, Postmenopausal/metabolism , Randomized Controlled Trials as Topic , Treatment Outcome
20.
Biol Reprod ; 62(4): 1033-9, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10727274

ABSTRACT

Calcitonin gene-related peptide (CGRP), a potent vasodilator primarily synthesized in dorsal root ganglia (DRG) neurons, has been shown to decrease vascular resistance and thus regulate blood flow to a variety of organs in rats. Serum CGRP levels in the human have been reported to increase with pregnancy and decrease postpartum. It has been suggested that female sex steroid hormones play a role in cardiovascular function, but the mechanisms are unknown. In this study, we examined the effects of estradiol-17beta (E(2)) and progesterone (P(4)) on the expression of CGRP in DRG in adult rats both in vivo and in vitro. Ovariectomized (ovx) animals were injected s.c. with 5 microg E(2), 4 mg P(4), or 5.0 microg E(2) + 4 mg P(4) in 0.5 ml sesame oil or with oil only, and groups of 4 rats were killed at 0, 24, or 48 h. DRGs were then removed and analyzed for CGRP mRNA and immunoreactive (i-)CGRP content by Northern blotting and RIA, respectively. Primary cultures of DRG neurons from adult female rats were used to assess the effects of varying doses of E(2) (1, 10, 100 nM), P(4) (10, 100, 1000 nM), or E(2) (10 nM) + P(4) (100 nM) in the absence or presence of nerve growth factor (NGF; 20 ng/ml); and CGRP mRNA content in the cells and i-CGRP in the medium were quantitated at 24 or 48 h after incubation. Results of in vivo studies showed that E(2) caused a significant increase in CGRP mRNA at 24 h (1.8-fold) and in i-CGRP levels both at 24 h (2. 8-fold) and at 48 h (3.4-fold) in DRG of ovx rats. P(4) also stimulated expression of both CGRP mRNA and i-CGRP. In the in vitro studies, either E(2) or P(4) alone or the two in combination were without effect on CGRP expression in cultured DRG neurons at all the doses tested. However, in the presence of NGF, both CGRP mRNA and peptide levels were significantly enhanced by E(2), P(4), and E(2)+P(4) in a time-dependent (2.0- to 2.8-fold at 24 h, 3.0- to 5. 0-fold at 48 h) and dose-dependent manner, with maximal effects achieved at 1.0 nM (E(2)) and 100 nM (P(4)) at 24 h of incubation. In summary, both E(2) and P(4), either alone or in combination, stimulate CGRP peptide synthesis in DRG neurons through increasing CGRP mRNA. The effects of these steroid hormones are mediated through amplifying the NGF-induced synthesis of CGRP in these neurons. Thus, we propose that the cardiovascular functions of female sex steroid hormones may be mediated, at least in part, by the up-regulation of neuronal CGRP synthesis, via NGF-mediated mechanisms.


Subject(s)
Calcitonin Gene-Related Peptide/biosynthesis , Ganglia, Spinal/metabolism , Gonadal Steroid Hormones/pharmacology , Animals , Cells, Cultured , Estradiol/pharmacology , Female , Ganglia, Spinal/drug effects , In Situ Hybridization , In Vitro Techniques , Nerve Growth Factors/biosynthesis , Ovariectomy , Progesterone/pharmacology , RNA/analysis , RNA/isolation & purification , RNA, Messenger/biosynthesis , Radioimmunoassay , Rats , Rats, Sprague-Dawley
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