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1.
J Contam Hydrol ; 264: 104365, 2024 May.
Article in English | MEDLINE | ID: mdl-38776560

ABSTRACT

Microplastics pollution is killing human life, contaminating our oceans, and lasting for longer in the environment than it is used. Microplastics have contaminated the geochemistry and turned the water system into trash barrel. Its detection in water is easy in comparison to soil and air so the attention of researchers is focused on it for now. Being very small in size, microplastics can easily cross the water filtration system and end up in the ocean or lakes and become the prospective challenge to aquatic life. This review piece provides the hot research theme and current advances in the field of microplastics and their eradication through the virtual world of artificial intelligence (AI) because Microplastics have confrontation with clean water tactics.


Subject(s)
Artificial Intelligence , Environmental Monitoring , Microplastics , Water Pollutants, Chemical , Microplastics/analysis , Water Pollutants, Chemical/analysis , Environmental Monitoring/methods
2.
Ann R Coll Surg Engl ; 99(2): 178-179, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27659355
3.
Vet World ; 9(3): 245-50, 2016 Mar.
Article in English | MEDLINE | ID: mdl-27057106

ABSTRACT

AIM: The present study was carried out to evaluate the effect of supplementation of garlic, ginger and their combination in the diets of broiler chickens and assessment in terms of feed intake, growth performance and economics of feeding. MATERIALS AND METHODS: A total of 240 1-day-old Cobb-400 broiler chicks were randomly assigned to four dietary treatments each with three replicates of 20 chicks per replicate (n=60). Four experimental diets were formulated in such a way that control diet (T1) contained neither ginger nor garlic. While, birds in group T2 and T3 were fed with diets containing 1% garlic and ginger, respectively. Diet 4 (T4 group) contained a combination of 1% of garlic and ginger. The feeding experiment was carried out for 42 days, and different parameters evaluated includes feed intake, weight gain, feed conversion ratio, gut morphometry, and economics of feeding in terms of return over feed cost (ROFC) and European Performance Efficiency Index. RESULTS: Feed intake of experimental birds in ginger and mixture of garlic and ginger supplemented groups, i.e., T3 and T4 groups have significantly (p<0.05) higher feed intake as compared to control. While, feeding of garlic have non-significant effect on feed intake as compared to other groups. A body weight gain (g/bird) was found to be significantly (p<0.05) higher in garlic (T2 group) and ginger (T3 group) supplemented group as compare to control and garlic and ginger mixture supplemented group (T4 group). Feed conversion ratio was significantly (p<0.05) lower in ginger (T3 group) supplemented group as compare to other groups. Mean villi length, villi width and cryptal depth were significantly (p<0.05) higher in T3 group than rest of all three groups, indicating increased absorptive surface area. ROFC was significantly (p<0.05) lower in T3 and T4 groups as compare to control. However, it was not significantly different between control and T2 group. CONCLUSION: On the basis of the results of the study, it is concluded that supplementation of garlic improves the performance of broilers when added at the rate of 1% of broiler ration and can be a viable alternative to antibiotic growth promoter in the feeding of broiler chicken.

4.
Neurogastroenterol Motil ; 27(8): 1162-74, 2015 Aug.
Article in English | MEDLINE | ID: mdl-26088546

ABSTRACT

BACKGROUND: Brain-derived neurotrophic factor (BDNF) is a neurotrophin present in the intestine where it participates in survival and growth of enteric neurons, augmentation of enteric circuits, and stimulation of intestinal peristalsis and propulsion. Previous studies largely focused on the role of neural and mucosal BDNF. The expression and release of BDNF from intestinal smooth muscle and the interaction with enteric neuropeptides has not been studied in gut. METHODS: The expression and secretion of BDNF from smooth muscle cultured from the rabbit intestinal longitudinal muscle layer in response to substance P (SP) and pituitary adenylate cyclase-activating peptide (PACAP) was measured by western blot and enzyme-linked immunosorbent assay. BDNF mRNA was measured by reverse-transcription polymerase chain reaction. KEY RESULTS: The expression of BNDF protein and mRNA was greater in smooth muscle cells (SMCs) from the longitudinal muscle than from circular muscle layer. PACAP and SP increased the expression of BDNF protein and mRNA in cultured longitudinal SMCs. PACAP and SP also stimulated the secretion of BDNF from cultured longitudinal SMCs. Chelation of intracellular calcium with BAPTA (1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) prevented SP-induced increase in BDNF mRNA and protein expression and SP-induced secretion of BDNF. CONCLUSIONS & INFERENCES: Neuropeptides known to be present in enteric neurons innervating the longitudinal layer increase the expression of BDNF mRNA and protein in SMCs and stimulate the release of BDNF. Considering the ability of BDNF to enhance smooth muscle contraction, this autocrine loop may partially explain the characteristic hypercontractility of longitudinal muscle in inflammatory bowel disease.


Subject(s)
Brain-Derived Neurotrophic Factor/metabolism , Pituitary Adenylate Cyclase-Activating Polypeptide/pharmacology , Substance P/pharmacology , Animals , Calcium Signaling , Intestines/drug effects , Intestines/physiology , Muscle, Smooth/drug effects , Muscle, Smooth/physiology , Rabbits
5.
Vet World ; 8(8): 989-93, 2015 Aug.
Article in English | MEDLINE | ID: mdl-27047187

ABSTRACT

AIM: To study the alteration of major milk components such as milk fat, protein, lactose, solid not fat (SNF) and total solids (TS) and their association with different degree of intra-mammary inflammation (IMI) in Jaffrabadi buffaloes. MATERIALS AND METHODS: Milk samples (n=1516) were collected from Jaffrabadi buffaloes separately from each quarter. Milk samples were analyzed for milk fat, protein, lactose, SNF and TS percent on the same day using milk analyzer "LACTOSCAN." Milk samples were checked for IMI by California mastitis test (CMT), and the results were expressed as negative (0), +, ++, and +++ CMT score. The traits of milk components which showed significant difference (p<0.05) between samples from inflamed and non-inflamed quarters were analyzed by receiver operating characteristic (ROC) analysis to see the accuracy and degree of association with IMI. RESULTS: Among several milk components, milk protein and lactose percent showed a significant difference (p<0.05) between milk samples from normal and inflamed quarters. Though, during the early stage of mammary gland inflammation milk protein percent remained significantly high (p<0.05), later with an increase in the degree of severity of inflammation it did not show any difference. Milk samples from normal udder quarters had significantly higher lactose percent than inflamed quarters (p<0.05). Milk lactose percent decreased gradually with an increase in the degree of severity of inflammation. ROC analysis revealed that milk samples having lactose content below the threshold values had significantly higher chances to come from inflamed udder quarters (p<0.05). Though, the value of the area under curve (AUC) indicated that milk lactose was significantly associated with IMI (p<0.05), the accuracy was moderate (AUC=0.71-0.75). CONCLUSIONS: The results of the present study indicated that milk lactose percent gradually and significantly reduced during IMI and can be used as a marker for identification of IMI in buffaloes. However, ROC analysis further confirmed that using milk lactose IMI can be identified with moderate accuracy.

6.
Niger Med J ; 55(2): 126-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24791045

ABSTRACT

BACKGROUND: Atrial septal defect (ASD) is a congenital heart defect that leads to shunting of blood between left and right atria. It may be asymptomatic and sometimes may present with heart failure. Surgical repair is definitive, but currently non-surgical procedure is used to close the defect. MATERIALS AND METHODS: It is a retrospective study of patients who underwent transcatheter closure of ASD at Innova Heart Hospital, Hyderabad, India. Echocardiography was repeated at intervals of 24 hours, then at 1, 3 and 6 months after the procedure to assess complications. The morphological characteristics of the ASD, including its diameter, location, shape and the width of surrounding septal margins, were also evaluated. RESULTS: From April 2007 to June 2011, 69 consecutive children (29 males, 40 females) with a median age of 9.0 years (range = 3.2-19 years) registered with diagnosis of ASD. The median weight was 31.5 kg (range = 7.5-39.0 kg). Five patients (7.2%) were young children aged 3-5 years. Forty-four (63.8%) of these children presented with symptoms of heart failure, whereas 47 (68.1%) of the cases repaired with device were large-sized ASD. The most common interventional procedures done were Searcare Heart(®) and Amplatzer(®) technique with a highest success rate obtained in 2010. CONCLUSIONS: ASD is a common congenital heart disease with a high success rate for those who undergo intervention.

7.
Am J Physiol Gastrointest Liver Physiol ; 306(4): G328-37, 2014 Feb 15.
Article in English | MEDLINE | ID: mdl-24356881

ABSTRACT

Brain-derived neurotrophic factor (BDNF) belongs to the neurotrophin family of proteins best known for its role in neuronal survival, differentiation, migration, and synaptic plasticity in central and peripheral neurons. BDNF is also widely expressed in nonneuronal tissues including the gastrointestinal tract. The role of BDNF in intestinal smooth muscle contractility is not well defined. The aim of this study was to identify the role of BDNF in carbachol (CCh)- and substance P (SP)-induced contraction of intestinal longitudinal smooth muscle. BDNF, selective tropomyosin-related kinase B (TrkB) receptor agonists, and pharmacological inhibitors of signaling pathways were examined for their effects on contraction of rabbit intestinal longitudinal muscle strips induced by CCh and SP. BDNF activation of intracellular signaling pathways was examined by Western blot in homogenates of muscle strips and isolated muscle cells. One-hour preincubation with BDNF enhanced intestinal muscle contraction induced by CCh but not by SP. The selective synthetic TrkB agonists LM 22A4 and 7,8-dihydroxyflavone produced similar effects to BDNF. The Trk antagonist K-252a, a TrkB antibody but not p75NTR antibody, blocked the effect of BDNF. The enhancement of CCh-induced contraction by BDNF was blocked by the phospholipase C (PLC) antagonist U73122, but not by ERK1/2 or Akt antagonists. Direct measurement in muscle strips and isolated muscle cells showed that BDNF caused phosphorylation of TrkB receptors and PLC-γ, but not ERK1/2 or Akt. We conclude that exogenous BDNF augments the CCh-induced contraction of longitudinal muscle from rabbit intestine by activating TrkB receptors and subsequent PLC activation.


Subject(s)
Brain-Derived Neurotrophic Factor/pharmacology , Carbachol/pharmacology , Cholinergic Agonists/pharmacology , Jejunum/drug effects , Muscle Contraction/drug effects , Muscle, Smooth/drug effects , Type C Phospholipases/metabolism , Animals , Dose-Response Relationship, Drug , Enzyme Activation , Enzyme Inhibitors/pharmacology , Jejunum/enzymology , Muscle, Smooth/enzymology , Phosphorylation , Rabbits , Receptor, trkB/drug effects , Receptor, trkB/metabolism , Signal Transduction/drug effects , Substance P/pharmacology , Type C Phospholipases/antagonists & inhibitors
8.
J Dairy Sci ; 95(1): 247-54, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22192204

ABSTRACT

The objective of the study was to estimate the prevalence and incidence of Mycoplasma bovis, a common cause of pneumonia, in veal calves. Using simple random sampling, 252 calves from 4 veal herds located in central Pennsylvania were selected and longitudinally followed for monthly collection of nasal swabs. Bronchial swabs and lung lesions were collected at the slaughterhouse. Nasal, bronchial, and lung lesion swabs were cultured for bacterial respiratory pathogens. Ninety lung lesions were identified, of which 41.1, 1.1, 1.1, 7.8, and 4.4% were culture positive for M. bovis alone, Pasteurella multocida alone, Mannheimia haemolytica alone, M. bovis and P. multocida co-infection, and M. bovis and M. haemolytica co-infection, respectively. The data indicate that potential interventions, such as therapeutics, vaccines, or management control measures, would be most effective before 50 d of age based upon the cumulative incidence of colonization.


Subject(s)
Mycoplasma Infections/veterinary , Mycoplasma bovis , Animals , Animals, Newborn/microbiology , Cattle , Incidence , Lung/microbiology , Mycoplasma Infections/epidemiology , Mycoplasma Infections/microbiology , Pennsylvania/epidemiology , Pneumonia, Bacterial/epidemiology , Pneumonia, Bacterial/microbiology , Pneumonia, Bacterial/veterinary , Prevalence , Respiratory System/microbiology
9.
Neurogastroenterol Motil ; 22(7): 779-86, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20331804

ABSTRACT

BACKGROUND: Glial cell line-derived neurotrophic factor (GDNF) is present in adult gut although its role in the mature enteric nervous system is not well defined. The aim of the present study was to examine the role of GDNF as neuromodulator of the ascending phase of the peristaltic reflex. METHODS: Colonic segments were prepared as flat sheets and placed in compartmented chambers so as to separate the sensory and motor limbs of the reflex. Ascending contraction was measured in the orad compartment and mucosal stroking stimuli (two to eight strokes) were applied in the caudad compartment. GDNF and substance P (SP) release were measured and the effects of GDNF and GDNF antibody on contraction and release were determined. Mice with reduced levels of GDNF (Gdnf(+/-)) and wild type littermates were also examined. KEY RESULTS: GDNF was released in a stimulus-dependent manner into the orad motor but not caudad sensory compartment. Addition of GDNF to the orad motor but not caudad sensory compartment augmented ascending contraction and SP release. Conversely, addition of GDNF antibody to the orad motor but not caudad sensory compartment reduced ascending contraction and SP release. Similarly, the ascending contraction and SP release into the orad motor compartment was reduced in Gdnf(+/-) mice as compared to wild type littermates. CONCLUSIONS & INFERENCES: The results suggest that endogenous GDNF is released during the ascending contraction component of the peristaltic reflex where it acts as a neuromodulator to augment SP release from motor neurons thereby augmenting contraction of circular muscle orad to the site of stimulation.


Subject(s)
Glial Cell Line-Derived Neurotrophic Factor/pharmacology , Peristalsis/drug effects , Substance P/metabolism , Animals , Colon/drug effects , Colon/physiology , Glial Cell Line-Derived Neurotrophic Factor/genetics , Glial Cell Line-Derived Neurotrophic Factor/physiology , Intestinal Mucosa/drug effects , Intestinal Mucosa/physiology , Intestines/physiology , Mice , Mice, Knockout , Muscle Contraction/physiology , Neurotransmitter Agents/physiology , Rats , Reflex/physiology
10.
Br J Pharmacol ; 153(6): 1214-24, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18204475

ABSTRACT

BACKGROUND AND PURPOSE: In gastrointestinal smooth muscle cGMP levels in response to relaxant agonists are regulated by PKG-mediated phosphorylation and activation of phosphodiesterase 5 (PDE5). The aim of the present study was to determine whether contractile agonists modulate cGMP levels by cross-regulating PDE5 activity and to identify the mechanism of action. EXPERIMENTAL APPROACH: Dispersed and cultured muscle cells from rabbit stomach were treated with the nitric oxide donor, S-nitrosoglutathione (GSNO), or with a contractile agonist, ACh and GSNO. PDE5 phosphorylation and activity, and cGMP levels were determined. KEY RESULTS: GSNO stimulated PDE5 phosphorylation and activity and increased cGMP levels in gastric smooth muscle cells. Concurrent activation of cells with ACh augmented GSNO-stimulated PDE5 phosphorylation and activity, and attenuated cGMP levels. The effect of ACh was blocked by the m3 receptor antagonist and by inhibitors of protein kinase C (PKC) or RhoA, but not by the m2 receptor antagonist or inhibitors of PI hydrolysis. The effects of ACh on PDE5 phosphorylation and activity, and cGMP levels were mimicked by a low concentration of tautomycin (10 nM), and a high (1 microM) but not low (1 nM) concentration of okadaic acid. PDE5 was associated with protein phosphatase 1 (PP1) and dephosphorylated by the catalytic subunit of PP1 but not PP2A. CONCLUSION AND IMPLICATIONS: In gastrointestinal smooth muscle cGMP levels are cross-regulated by contractile agonists via a mechanism that involves RhoA-dependent, PKC-mediated inhibition of PP1 activity. This leads to augmentation of PDE5 phosphorylation and activity, and inhibition of cGMP levels.


Subject(s)
Cyclic GMP/metabolism , Cyclic Nucleotide Phosphodiesterases, Type 5/drug effects , Receptor, Muscarinic M3/agonists , S-Nitrosoglutathione/pharmacology , Acetylcholine/pharmacology , Animals , Cyclic Nucleotide Phosphodiesterases, Type 5/metabolism , In Vitro Techniques , Myocytes, Smooth Muscle/drug effects , Myocytes, Smooth Muscle/metabolism , Phosphorylation/drug effects , Protein Kinase C/drug effects , Protein Kinase C/metabolism , Protein Phosphatase 1/antagonists & inhibitors , Protein Phosphatase 1/metabolism , Rabbits , Receptor, Muscarinic M3/metabolism , Stomach/cytology , rhoA GTP-Binding Protein/drug effects , rhoA GTP-Binding Protein/metabolism
12.
Indian J Exp Biol ; 44(7): 584-90, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16872050

ABSTRACT

A strain of T. chilonis, an egg parasitoid of lepidopteran pests tolerant to the most commonly used cyclodiene insecticide--endosulfan was developed in the laboratory. Tolerance to endosulfan was induced by exposing adult parasitoids sequentially from a sub-lethal concentration (0.004%) to the field recommended concentration (0.09%). The strain acquired tolerance to the insecticide after 341 generation of continuous exposure with LC50 values of 1074.96 ppm as compared to LC50 of (70.91 ppm) in susceptible strain. The genetical study showed that F1 crosses exhibited a semi-dominant response to endosulfan with degree of dominance value (D) of 0.58. The resistant factor of tolerant strain was 15.1 folds and of F1 cross were 8.53 folds over susceptible strain. Under net house conditions, the tolerant strain parasitised 56% Helicoverpa armigera eggs on potted cotton plants immediately after an insecticide spray, compared to 3% by the susceptible strain. High percentage survival of the immature stages of the tolerant strain proved their ability to withstand the insecticide load. Breakdown of insecticide tolerance in the strain occurred after four generations in absence of insecticide load. Use of the tolerant strain as a component of bio-intensive IPM in various crops where insecticide use is higher is discussed.


Subject(s)
Endosulfan/pharmacology , Hymenoptera , Insecticide Resistance/genetics , Insecticides/pharmacology , Pest Control, Biological , Animals , Crosses, Genetic , Hymenoptera/drug effects , Hymenoptera/genetics , Hymenoptera/growth & development , Lepidoptera/parasitology , Ovum/parasitology
13.
J Environ Manage ; 81(3): 265-72, 2006 Nov.
Article in English | MEDLINE | ID: mdl-16580120

ABSTRACT

The sorption and desorption of cadmium and zinc on zeolite 4A, zeolite 13X and bentonite has been studied using batch sorption studies. Parameters such as equilibrium time, effect of pH and sorbent dose were studied. The sorbents exhibited good sorption potential for cadmium and zinc with a peak value at pH 6.0 and 6.5, respectively. The sorption followed the Freundlich sorption model. More than 70% sorption occurred within 20 min and equilibrium was attained at around 90 min for the three sorbents. The metals sorption by zeolite 4A was higher than that by zeolite 13X and bentonite. The desorption studies were carried out using NaCl solution and the effect of NaCl concentration on desorption was also studied. Maximum desorption of 76% for cadmium and 80% for zinc occurred with 10% NaCl.


Subject(s)
Bentonite/chemistry , Cadmium/isolation & purification , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Zeolites/chemistry , Zinc/isolation & purification , Adsorption , Dose-Response Relationship, Drug , Hydrogen-Ion Concentration , Industrial Waste , Kinetics , Sodium Chloride/chemistry
14.
Int J Pharm ; 282(1-2): 73-85, 2004 Sep 10.
Article in English | MEDLINE | ID: mdl-15336383

ABSTRACT

Understanding the polymorphic behavior of pharmaceutical solids during the crystallization process and further in post-processing units is crucial to meet medical and legal requirements. In this study, an analytical technique was developed for determining the composition of two solid forms of ranitidine hydrochloride using two peaks of Fourier transform infrared (FTIR) spectra without the need to grind the samples. Solubility studies of ranitidine hydrochloride showed that Form 2 has a higher solubility than Form 1. Solution-mediated transformation is very slow and occurs from Form 2 to Form 1 and not the reverse. No solid-solid transformation was observed due to grinding or compressing the pure samples of either forms and of a 50/50 wt.% mixture. Grinding was found to be a proper technique for increasing the bulk solid density of the ranitidine hydrochloride without the risk of solid-solid transformation. Dissolution rate found to be equally fast for both forms. The solubility data were modeled using the group contribution parameters and UNIversal QUAsi-Chemical (UNIQUAC) theory. There was a good agreement between the experimental solubility data of ranitidine hydrochloride and the results of UNIQUAC equation.


Subject(s)
Anti-Ulcer Agents/chemistry , Ranitidine/chemistry , Calorimetry, Differential Scanning , Chemical Phenomena , Chemistry, Physical , Drug Compounding , Hydrochloric Acid/chemistry , Hydrogen-Ion Concentration , Isomerism , Kinetics , Microscopy, Electron, Scanning , Software , Solubility , Solutions , Solvents , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared , Thermodynamics , Ultrasonics
15.
J Pharm Sci ; 93(7): 1692-700, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15176059

ABSTRACT

Ranitidine hydrochloride Form 1 produced by the original method (Price et al., 1978 US patent) has poor filtration and drying characteristics, which make it less desirable commercially in comparison with Form 2. This article shows that the operating parameters have significant influence on the final properties of Form 1. In terms of filterability and solid bulk density, it was found that at a higher temperature (approximately 48 degrees C), the viscosity of the slurry decreased and improved product quality as compared with operating at room temperature (approximately 25 degrees C). It was found that the rapid addition of acid to the ranitidine base increased product density but led to higher residual solvent inclusion. The presence of excess ranitidine base in the solution and also the manner of reactant addition had a significant influence on the onset of nucleation and the rate of crystallization. The best results in terms of filterability and bulk solid density were obtained using an initial pH of 5.3 and then increasing it to 6.3-6.4 after the onset of nucleation.


Subject(s)
Ranitidine/chemistry , Chemistry, Pharmaceutical , Filtration/instrumentation , Filtration/methods , Hydrogen-Ion Concentration
16.
Indian Heart J ; 56(6): 673-6, 2004.
Article in English | MEDLINE | ID: mdl-15751528

ABSTRACT

Transcatheter balloon recanalization of occluded Blalock-Taussig shunts in the early post-operative period has been reported in the past but there are issues regarding the role of thrombolysis in this situation. We present our experience with such a procedure in an infant with blocked modified Blalock-Taussig shunt.


Subject(s)
Coronary Thrombosis/diagnosis , Coronary Thrombosis/therapy , Anastomosis, Surgical/adverse effects , Angioplasty, Balloon, Coronary , Coronary Angiography , Coronary Thrombosis/diagnostic imaging , Coronary Thrombosis/etiology , Diagnosis, Differential , Heart Defects, Congenital/surgery , Humans , Infant , Male
17.
Indian Heart J ; 55(1): 68-70, 2003.
Article in English | MEDLINE | ID: mdl-12760592

ABSTRACT

Complete heart block following intracardiac surgical repair for complex congenital heart disease is not uncommon. In the presence of ventricular dysfunction, ventricular pacing alone may not improve the cardiac output. We report the feasibility and efficacy of endoepicardial atrioventricular sequential pacing in a case of postoperative complete heart block.


Subject(s)
Cardiac Pacing, Artificial , Cardiac Surgical Procedures/adverse effects , Heart Block/therapy , Heart Defects, Congenital/surgery , Child , Electrocardiography , Female , Heart Block/etiology , Humans
18.
Biochem J ; 360(Pt 1): 199-208, 2001 Nov 15.
Article in English | MEDLINE | ID: mdl-11696008

ABSTRACT

The regulation of cGMP-specific phosphodiesterase (PDE) 5 and soluble guanylate cyclase (GC) by cGMP- and cAMP-dependent protein kinases (PKG and PKA respectively) was examined in gastric smooth muscle. The NO donor, sodium nitroprusside (SNP), stimulated PDE5 phosphorylation and activity, which was blocked by the selective PKG inhibitor, KT5823, resulting in an elevation of cGMP levels. Activation of PKA either directly by Sp-5,6-dichloro-1-beta-d-ribofuranosyl benzimidazole 3',5'-cyclic monophosphothioate, or via isoproterenol- and forskolin-dependent increase in cAMP, also caused an increase in PDE5 phosphorylation and activity, but only in the presence of cGMP; consistent with the dependence of PDE5 phosphorylation and activity on cGMP binding to allosteric sites in the regulatory domain of PDE5. The selective PKA inhibitors, myristoylated protein kinase inhibitor and H-89, blocked the increase in PDE5 phosphorylation and activity induced by PKA. SNP also stimulated soluble GC phosphorylation and activity. KT5823 abolished phosphorylation and augmented soluble GC activity, implying feedback inhibition of soluble GC by PKG-dependent phosphorylation. Phosphorylation by PKG was direct and could be induced in vitro. Activation of PKA had no effect on soluble GC. Thus cGMP levels are regulated by PKG- and PKA-dependent activation of PDE5 and PKG-specific inhibition of soluble GC.


Subject(s)
Carbazoles , Cyclic GMP-Dependent Protein Kinases/metabolism , Guanylate Cyclase/antagonists & inhibitors , Indoles , Intestine, Small/enzymology , Muscle, Smooth/enzymology , Phosphoric Diester Hydrolases/metabolism , 3',5'-Cyclic-GMP Phosphodiesterases , Alkaloids/pharmacology , Allosteric Site , Animals , Blotting, Western , Cattle , Cells, Cultured , Cyclic AMP/metabolism , Cyclic AMP-Dependent Protein Kinases/metabolism , Cyclic GMP/metabolism , Cyclic Nucleotide Phosphodiesterases, Type 5 , Dose-Response Relationship, Drug , Enzyme Activation , Enzyme Inhibitors/pharmacology , Marine Toxins , Models, Biological , Nitroprusside/pharmacology , Oxazoles/pharmacology , Phosphorylation , Precipitin Tests , Protein Structure, Tertiary , Rabbits , Radioimmunoassay
19.
Am J Physiol Gastrointest Liver Physiol ; 281(5): G1238-45, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11668033

ABSTRACT

The singular effects and interplay of cAMP- and cGMP-dependent protein kinase (PKA and PKG) on Ca(2+) mobilization were examined in dispersed smooth muscle cells. In permeabilized muscle cells, exogenous cAMP and cGMP inhibited inositol 1,4,5-trisphosphate (IP(3))-induced Ca(2+) release and muscle contraction via PKA and PKG, respectively. A combination of cAMP and cGMP caused synergistic inhibition that was exclusively mediated by PKG and attenuated by PKA. In intact muscle cells, low concentrations (10 nM) of isoproterenol and sodium nitroprusside (SNP) inhibited agonist-induced, IP(3)-dependent Ca(2+) release and muscle contraction via PKA and PKG, respectively. A combination of isoproterenol and SNP increased PKA and PKG activities: the increase in PKA activity reflected inhibition of phosphodiesterase 3 activity by cGMP, whereas the increase in PKG activity reflected activation of cGMP-primed PKG by cAMP. Inhibition of Ca(2+) release and muscle contraction by the combination of isoproterenol and SNP was preferentially mediated by PKG. In light of studies showing that PKG phosphorylates the IP(3) receptor in intact and permeabilized muscle cells, whereas PKA phosphorylates the receptor in permeabilized cells only, the results imply that inhibition of IP(3)-induced Ca(2+) release is mediated exclusively by PKG. The effect of PKA on agonist-induced Ca(2+) release probably reflects inhibition of IP(3) formation.


Subject(s)
Calcium/metabolism , Cyclic AMP/pharmacology , Cyclic GMP-Dependent Protein Kinases/metabolism , Cyclic GMP/pharmacology , Inositol 1,4,5-Trisphosphate/physiology , Animals , Cells, Cultured , Drug Synergism , Enzyme Activation/physiology , Muscle Contraction/drug effects , Muscle, Smooth/cytology , Muscle, Smooth/drug effects , Muscle, Smooth/physiology , Rabbits
20.
Int J Toxicol ; 20(3): 113-20, 2001.
Article in English | MEDLINE | ID: mdl-11488553

ABSTRACT

Environmental exposure to lead (Pb) is known to affect the developing nervous system causing cognitive deficits in children. The diffusible nitric oxide (NO) is a biological messenger known to be involved in brain development. We examined the developmental changes of neuronal nitric oxide synthase (nNOS) in cerebellum and hippocampus of developing rat brain by radiometric assay, Western blot analysis and immunohistochemistry. Pb-exposure (0.2% Pb acetate) was initiated on gestation day 6 through the drinking water of the dam and continued through birth and postnatal days (PNDs) 1 to 21. The pups were never exposed to Pb directly. Pb exposure was stopped on weaning of pups from mothers on PND 21. The changes in nNOS were measured in the offspring on PNDs 7, 14, 21, and 35. The nNOS activity was increased gradually from PNDs 7 to 35 in both cerebellum and hippocampus of control rats when the enzyme activity was determined in the presence of either 0.5 or 6 microM calcium (Ca2+) in the reaction mixture. However, Pb exposure decreased the nNOS activity significantly at PNDs 21 to 35 as compared to respective controls when the enzyme activity was determined in the presence of 6 microM Ca2+. The decrease of nNOS was even greater and evident at all PNDs tested when the enzyme activity was assayed in the presence of physiological concentration of Ca2+ (0.5 microM). These findings were further strengthened by the in vitro studies. The cerebellar nNOS activity was inhibited much more at low Ca2+ (0.5 microM) as compared to 6 microM Ca2+, with IC50 values of 35 and 50 nM Pb, respectively. The nNOS protein levels and immunoreactivity in the cerebellum and hippocampus of rats perinatally exposed to Pb were decreased as compared to controls at PNDs 21 and 35. These data suggest perinatal Pb exposure decreases the nNOS in the developing brain. The decrease of nNOS activity and protein may explain the Pb-mediated cognitive deficits because NO regulates long-term potentiation (LTP) and other neurophysiological events in the developing nervous system.


Subject(s)
Cerebellum/enzymology , Hippocampus/enzymology , Lead/adverse effects , Nitric Oxide Synthase/biosynthesis , Nitric Oxide Synthase/drug effects , Prenatal Exposure Delayed Effects , Administration, Oral , Animals , Blotting, Western , Cerebellum/drug effects , Cerebellum/growth & development , Female , Hippocampus/drug effects , Hippocampus/growth & development , Immunohistochemistry , Male , Neurons/enzymology , Pregnancy , Rats , Rats, Sprague-Dawley
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