Mu-opioid receptors in the paraventricular nucleus regulate ejaculatory behaviors via the sympathetic nerve system in male rats / 中华男科学杂志

Objective@#To explore the effects of the mu-opioid receptor (MOR) in the paraventricular nucleus (PVN) on the ejaculatory behaviors of male rats and its potential mechanisms.@*METHODS@#Male SD rats with normal ejaculation ability were mated with female ones in hormone-induced estrus. After bilateral PVN microinjection of D-Ala-2-Me-Phe-4-Gly-ol enkephalin (DAGO) or D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP) with an inserted catheter, the male animals were observed for mount latency (ML), mount frequency (MF), intromission latency (IL), intromission frequency (IF), ejaculation latency (EL), ejaculation frequency (EF), post-ejaculation interval (PEI), and intromission ratio (IR). The lumbar sympathetic nerve activity (LSNA) of the rats was recorded using the PowerLab data acquisition hardware device, and the levels of norepinephrine (NE) in the peripheral plasma were measured by ELISA following microinjection of saline or different doses of DAGO or CTAP.@*RESULTS@#Neither CTAP nor DGAO significantly affected the ML of the male rats (P > 0.05). DGAO remarkably increased IF (P < 0.01) and MF (P < 0.01), prolonged IL (P < 0.01), EL (P < 0.01) and PEI (P < 0.01), and reduced EF (P <0.01) and IR (P < 0.05). On the contrary, CTAP markedly decreased IF (P < 0.01) and MF (P < 0.01), shortened IL (P < 0.01), EL (P < 0.01) and PFI (P < 0.01), and elevated EF (P < 0.01) and IR (P < 0.01). Additionally, DAGO decreased LSNA in a dose-dependent manner and reduced the NE level in the peripheral plasma. CTAP, however, not only offset the effects of DAGO on LSNA, but also significantly increased LSNA.@*CONCLUSIONS@#MOR in PVN inhibits ejaculatory behaviors in male rats by weakening LSNA, which has provided some theoretical evidence for the use of highly selective opioids in the treatment of premature ejaculation.

Influence of antihypertensive drugs on aortic and coronary effects of Ang-(1-7) in pressure-overloaded rats

This study investigated the influence of antihypertensive drugs, such as angiotensin-converting enzyme inhibitors (ACEIs), AT1 receptor blockers (ARBs), voltage-gated L-type calcium channel blockers, and mineralocorticoid receptor antagonists (MRAs), on the effects of angiotensin-(1-7) [Ang-(1-7)] on aorta and coronary arteries from pressure-overloaded rats. Pressure overload was induced by abdominal aortic banding (AB). To evaluate the role of antihypertensive drugs on the effect of Ang-(1-7), AB male Wistar rats weighing 250–300 g were treated with vehicle or low doses (5 mg·kg-1·day-1, gavage) of losartan, captopril, amlodipine, or spironolactone. Isolated aortic rings and isolated perfused hearts under constant flow were used to evaluate the effect of Ang-(1-7) in thoracic aorta and coronary arteries, respectively. Ang-(1-7) induced a significant relaxation in the aorta of sham animals, but this effect was reduced in the aortas of AB rats. Chronic treatments with losartan, captopril or amlodipine, but not with spironolactone, restored the Ang-(1-7)-induced aorta relaxation in AB rats. The coronary vasodilatation evoked by Ang-(1-7) in sham rats was blunted in hypertrophic rats. Only the treatment with losartan restored the coronary vasodilatory effect of Ang-(1-7) in AB rat hearts. These data support a beneficial vascular effect of an association of Ang-(1-7) and some antihypertensive drugs. Thus, this association may have potential as a new therapeutic strategy for cardiovascular diseases.

Angiotensin- (1-7) inhibits inflammation and oxidative stress to relieve lung injury induced by chronic intermittent hypoxia in rats

Obstructive sleep apnea is associated with inflammation and oxidative stress in lung tissues and can lead to metabolic abnormalities. We investigated the effects of angiotensin1–7 [Ang-(1–7)] on lung injury in rats induced by chronic intermittent hypoxia (CIH). We randomly assigned 32 male Sprague-Dawley rats (180–200 g) to normoxia control (NC), CIH-untreated (uCIH), Ang-(1–7)-treated normoxia control (N-A), and Ang-(1–7)-treated CIH (CIH-A) groups. Oxidative stress biomarkers were measured in lung tissues, and expression of NADPH oxidase 4 (Nox4) and Nox subunits (p22phox, and p47phox) was determined by Western blot and reverse transcription-polymerase chain reaction. Pulmonary pathological changes were more evident in the uCIH group than in the other groups. Enzyme-linked immunosorbent assays and immunohistochemical staining showed that inflammatory factor concentrations in serum and lung tissues in the uCIH group were significantly higher than those in the NC and N-A groups. Expression of inflammatory factors was significantly higher in the CIH-A group than in the NC and N-A groups, but was lower than in the uCIH group (P<0.01). Oxidative stress was markedly higher in the uCIH group than in the NC and N-A groups. Expression of Nox4 and its subunits was also increased in the uCIH group. These changes were attenuated upon Ang-(1–7) treatment. In summary, treatment with Ang-(1-7) reversed signs of CIH-induced lung injury via inhibition of inflammation and oxidative stress.

Angiotensina-(1-9) disminuye el daño renal en la hipertensión arterial renina independiente / Angiotensin (1-9) decreases renal damage in hypertension with low renin

Antecedentes: Angiotensina [Ang-(1-9)] disminuye la presión arterial (PA) y el remodel amiento cardíaco en la hipertensión arterial experimental independiente de renina. No hay antecedentes sobre el efecto de Ang-(1-9) en la progresión de daño renal de ratas hipertensas por expansión de volumen (con renina baja). Objetivo: Determinar la participación de Ang-(1-9) en la progresión del daño renal en ratas hipertensas (DOCA-sal). Métodos: Se utilizaron ratas Sprague Dawley macho de 150 +/- 10 g uninefrectomizadas tratadas con DOCA (60mg/Kg/2 veces sem, im) por 4 semanas. Como controles (Sham) se usaron ratas uninefrectomizadas. Desde la 2a semana las ratas DOCA, con presión arterial sistólica (PAS) > 140 mmHg, recibieron vehículo o Ang-(1-9) [602 ng/Kg min] por 2 semanas (minibomba Alzet). Se evaluó la respuesta inflamatoria y el daño renal profibrótico por la presencia de macrófagos infiltrativos y de mio-fibroblastos intersticiales. Se determinó, además, la presión arterial sistólica (PAS), masa corporal (MC), masa del riñón derecho (MR) y masa renal relativa (MRR). Resultados: Se observó una disminución del daño renal en las ratas DOCA-sal, cuando recibieron Ang-(1-9), respecto a aquellas que no la recibieron, evidenciado por una significativa disminución de macrófagos infiltrativos y miofibroblastos en el intersticio renal. El bloqueo de los receptores Mas y AT2, no tuvieron efectos adicionales. Conclusion: En este modelo experimental, Ang-(1-9) disminuyó la hipertensión y redujo significativamente la infiltración de macrófagos y la aparición de miofibroblastos en el intersticio renal. Estos resultados son la primera evidencia de que Ang-(1-9) reduce la fibrosis túbulo-intersticial renal y el daño renal hipertensivo.

Angiotensin [Ang] - (1-9) decreases blood pressure (BP) and cardiac remodeling in renin independent hypertension. There are not studies about the effect of Ang- (1-9) in the progression of hypertensive renal damage by volume overload (low-renin). The aim of this study was to determine the effect of Ang- (1-9) on renal damage in volume overload hypertensive rats by (DOCA-salt rats). Methods: Male Sprague Dawley rats, 150 +/- 10 g, were uni-nephrectomized and treated with DOCA (60mg/Kg) 2 times per week, for 4 weeks. Uninephrec-tomized rats were used as controls (Sham). From the 2nd week on DOCA rats with systolic blood pressure (SBP)> 140 mmHg received vehicle or Ang- (1-9) [602 ng / kg min] for 2 weeks (Alzet minipump). Inflammatory and profibrotic renal damage was evaluated by the presence of infiltrating macrophages and interstitial myofibroblasts. Results: Compared to rats receiving vehicle renal damage in DOCA-salt rats decreased when they received Ang- (1-9), as evidenced by a significant decrease in infiltrating macrophages and myofibroblasts in the renal interstitium. Mas and AT2 receptor blockade had no additional effect. The SBP, body mass (BM), mass of the right kidney (MR) and relative renal mass (MRR) were also determined. Conclusion: in this experimental model, Ang-(1-9) decreased hypertension and significantly reduced macrophage infiltration and the appearance of myofibroblasts in the renal interstitium. These results are the first evidence that Ang-(1-9) reduces renal tubulointerstitial fibrosis and hypertensive renal damage.

Anti-proliferative and apoptotic properties of a peptide from the seeds of Polyalthia longifolia against human cancer cell lines.

The peptides produced enzymatically from various plants have shown various biological activities including cytotoxicity. Different types of cytotoxic peptides have been reported from the seeds and leaves of Violaceae, Rubiaceae and Annonaceae families. In this study, we report purification and characterization of peptide(s) showing cytotoxic activity against A549 and HeLa cancer cell lines from the seeds of Polyalthia longifolia (Annonaceae). Seed proteins of P. longifolia were extracted and hydrolyzed using trypsin. The enzyme hydrolysate was applied on to a Sephadex G10 column and eluted using Tris-HCl buffer (pH 7.5). Two fractions F1 and F2 were obtained, of which F2 showed significant cytotoxic activity against lung (A549) cancer cells at 10 µg/mL and cervical (HeLa) cancer cell lines at 30 µg/mL, as revealed by the MTT assay. DNA fragmentation was observed in the tested cancer cell lines treated with F2 peptide at a concentration of 10 µg/mL and 30 µg/mL, respectively. Further, increased number of apoptotic cells was observed in sub-G0 phase of cell cycle of A549 and HeLa cell lines, when treated with 10 µg/mL and 30 µg/mL of F2, as revealed by the flow cytometric analyses. FTIR spectrum of F2 peptide detected the presence of stretching vibrations of carboxylic acid OH residue with peak at 3420 cm-1 and carbonyl (C=O) groups at 1636 cm-1, respectively. RP-HPLC analysis of F2 peptide showed a single peak at a retention time of 12.8 min detected at 280 nm, depicting the purity of F2 to be more than 90%. LC-ESI-MS/MS analysis showed the average theoretical mass of F2 to be 679.8 using m/z ratios. In conclusion, the findings suggest that F2 peptide is an effective inducer of apoptosis of cancer cells, thus offers an important strategy in the development of cancer therapeutics.

Characterization of Gp41 Polymorphisms in the Fusion Peptide Domain and T-20 (Enfuvirtide) Resistance-Associated Regions in Korean HIV-1 Isolates

HIV-1 gp41 is an envelope protein that plays an essential role in virus entry. The mutation of gp41 affects HIV-1 entry and susceptibility to the fusion inhibitor T-20. Therefore, we analyzed the natural polymorphism of gp41 of 163 HIV-1 isolates from T-20-naive Koreans infected with HIV-1. This study of gp41 polymorphisms showed that insertions in the fourth threonine (74.8%) and L7M substitutions (85.3%) were more frequent in the fusion peptide motif in Korean HIV-1 isolates compared with those from other countries. Minor T-20 resistance mutations such as L45M (1.2%), N126K (1.2%), and E137K (6.7%) were detected, but the critical T-20 resistance mutations were not detected in the gp41 HR1 and HR2 regions. In addition, the N42S mutation (12.9%) associated with T-20 hypersusceptibility was detected at a high frequency. These results may serve as useful data for studies considering T-20 for use in the development of a more effective anti-retroviral treatment in Korea.

The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms

OBJECTIVE: In the present study, the peripheral mechanism that mediates the pressor effect of angiotensin-(1-7) in the rostral ventrolateral medulla was investigated. METHOD: Angiotensin-(1-7) (25 pmol) was bilaterally microinjected in the rostral ventrolateral medulla near the ventral surface in urethane-anesthetized male Wistar rats that were untreated or treated (intravenously) with effective doses of selective autonomic receptor antagonists (atenolol, prazosin, methyl-atropine, and hexamethonium) or a vasopressin V1 receptor antagonist [d(CH2)5 -Tyr(Me)-AVP] given alone or in combination. RESULTS: Unexpectedly, the pressor response produced by angiotensin-(1-7) (16 ± 2 mmHg, n = 12), which was not associated with significant changes in heart rate, was not significantly altered by peripheral treatment with prazosin, the vasopressin V1 receptor antagonist, hexamethonium or methyl-atropine. Similar results were obtained in experiments that tested the association of prazosin and atenolol; methyl-atropine and the vasopressin V1 antagonist or methyl-atropine and prazosin. Peripheral treatment with the combination of prazosin, atenolol and the vasopressin V1 antagonist abolished the pressor effect of glutamate; however, this treatment produced only a small decrease in the pressor effect of angiotensin-(1-7) at the rostral ventrolateral medulla. The combination of hexamethonium with the vasopressin V1 receptor antagonist or the combination of prazosin, atenolol, the vasopressin V1 receptor antagonist and methyl-atropine was effective in blocking the effect of angiotensin-(1-7) at the rostral ventrolateral medulla. CONCLUSION: These results indicate that angiotensin-(1-7) triggers a complex pressor response at the rostral ventrolateral medulla that involves an increase in sympathetic tonus, release of vasopressin and possibly the inhibition of a vasodilatory mechanism.

Structure-activity relationship of buffalo antibacterial hepcidin analogs.

Hepcidin is an anti-microbial peptide expressed predominantly in the liver of many species. Based on the amino acid sequence deduced from buffalo (Bubalus bubalis) hepcidin cDNA (Accession no. EU399814), six peptides Hepc1-25, Hepc6-25, Hepc7-25, Hepc9-25, Hepc11-25 and Hepc15-25 were synthesized using solid-phase fluorenylmethoxycarbonyl (Fmoc) chemistry. CD spectroscopy revealed different spectra of the peptides in different solvents and in all the cases b-structure was found to be dominant with less a-helix as predicted. Quantitation of secondary structure indicated the highest b-structure for all the six peptides in SDS solution, when used as mimetic for membrane-like environment. The CD spectra of all the peptides taken in water showed that degree of randomness decreased with increase in chain length of the peptide. Out of the six peptides, only Hepc1-25, Hepc6-25 and Hepc7-25 showed antibacterial activity against Staphylococcus aureus (Gram-positive bacteria). The peptides did not show any sensitivity toward E. coli (Gram-negative bacteria). Minimum inhibitory concentration (MIC) showed the lowest value for Hepc7-25 as an antibacterial agent, followed by Hepc6-25 and Hepc1-25. The peptides Hepc9-25, Hepc11-25 and Hepc15-25 with more random structure did not show any antimicrobial activity The study demonstrated that 5 amino acids at N-terminal in buffalo hepcidin can be truncated without loss of antimicrobial activity and further reduction of length of the analog from 20 to 19 amino acids resulted increase in the activity because of increase in -structure of the peptide shown by CD spectroscopy.

Role of Corticotrophin-releasing Factor in the Stress-induced Dilation of Esophageal Intercellular Spaces

Corticotrophin-releasing factor (CRF) plays a major role in coordinating stress responses. We aimed to test whether blocking endogenous CRF activity can prevent the stress-induced dilation of intercellular spaces in esophageal mucosa. Eighteen adult male rats were divided into 3 groups: 1) a non-stressed group (the non-stressed group), 2) a saline-pretreated stressed group (the stressed group), 3) and an astressin-pretreated stressed group (the astressin group). Immediately after completing the experiments according to the protocol, distal esophageal segments were obtained. Intercellular space diameters of esophageal mucosa were measured by transmission electron microscopy. Blood was sampled for the measurement of plasma cortisol levels. Mucosal intercellular spaces were significantly greater in the stressed group than in the non-stressed group. Mucosal intercellular spaces of the astressin group were significantly smaller than those of the stressed group. Plasma cortisol levels in the stressed group were significantly higher than in the non-stressed group. Pretreatment with astressin tended to decrease plasma cortisol levels. Acute stress in rats enlarges esophageal intercellular spaces, and this stress-induced alteration appears to be mediated by CRF. Our results suggest that CRF may play a role in the pathophysiology of reflux-induced symptoms or mucosal damage.

The N- and C-terminal domains of parathyroid hormone-related protein affect differently the osteogenic and adipogenic potential of human mesenchymal stem cells

Parathyroid hormone-related protein (PTHrP) is synthesized by diverse tissues, and its processing produces several fragments, each with apparently distinct autocrine and paracrine bioactivities. In bone, PTHrP appears to modulate bone formation in part through promoting osteoblast differentiation. The putative effect of PTH-like and PTH-unrelated fragments of PTHrP on human mesenchymal stem cell (MSCs) is not well known. Human MSCs were treated with PTHrP (1-36) or PTHrP (107-139) or both (each at 10 nM) in osteogenic or adipogenic medium, from the start or after 6 days of exposure to the corresponding medium, and the expression of several osteoblastogenic and adipogenic markers was analyzed. PTHrP (1-36) inhibited adipogenesis in MSCs and favoured the expression of osteogenic early markers. The opposite was observed with treatment of MSCs with PTHrP (107-139). Moreover, inhibition of the adipogenic differentiation by PTHrP (1-36) prevailed in the presence of PTHrP (107-139). The PTH/PTHrP type 1 receptor (PTH1R) gene expression was maximum in the earlier and later stages of osteogenesis and adipogenesis, respectively. While PTHrP (107-139) did not modify the PTH1R overexpression during adipogenesis, PTHrP (1-36) did inhibit it; an effect which was partially affected by PTHrP (7-34), a PTH1R antagonist, at 1 microM. These findings demonstrate that both PTHrP domains can exert varying effects on human MSCs differentiation. PTHrP (107-139) showed a tendency to favor adipogenesis, while PTHrP (1-36) induced a mild osteogenic effect in these cells, and inhibited their adipocytic commitment. This further supports the potential anabolic action of the latter peptide in humans.

Stress-induced Alterations in Mast Cell Numbers and Proteinase-activated Receptor-2 Expression of the Colon: Role of Corticotrophin-releasing Factor

This study was performed in order to assess whether acute stress can increase mast cell and enterochromaffin (EC) cell numbers, and proteinase-activated receptor-2 (PAR2) expression in the rat colon. In addition, we aimed to investigate the involvement of corticotrophin-releasing factor in these stress-related alterations. Eighteen adult rats were divided into 3 experimental groups: 1) a saline-pretreated non-stressed group, 2) a saline-pretreated stressed group, and 3) an astressin-pretreated stressed group. The numbers of mast cells, EC cells, and PAR2-positive cells were counted in 6 high power fields. In proximal colonic segments, mast cell numbers of stressed rats tended to be higher than those of non-stressed rats, and their PAR2-positive cell numbers were significantly higher than those of non-stressed rats. In distal colonic segments, mast cell numbers and PAR2-positive cell numbers of stressed rats were significantly higher than those of non-stressed rats. Mast cell and PAR2-positive cell numbers of astressin-pretreated stressed rats were significantly lower than those of saline-pretreated stressed rats. EC cell numbers did not differ among the three experimental groups. Acute stress in rats increases mast cell numbers and mucosal PAR2 expression in the colon. These stress-related alterations seem to be mediated by release of corticotrophin-releasing factor.

Activation of nicotinic acetylcholine receptor prevents the production of reactive oxygen species in fibrillar beta amyloid peptide (1-42)-stimulated microglia

Recent studies have reported that the "cholinergic anti-inflammatory pathway" regulates peripheral inflammatory responses via alpha7 nicotinic acetylcholine receptors (alpha7 nAChRs) and that acetylcholine and nicotine regulate the expression of proinflammatory mediators such as TNF-alpha and prostaglandin E2 in microglial cultures. In a previous study we showed that ATP released by beta-amyloid-stimulated microglia induced reactive oxygen species (ROS) production, in a process involving the P2X7 receptor (P2X7R), in an autocrine fashion. These observations led us to investigate whether stimulation by nicotine could regulate fibrillar beta amyloid peptide (1-42) (fA beta(1-42))-induced ROS production by modulating ATP efflux-mediated Ca2+ influx through P2X7R. Nicotine inhibited ROS generation in fA beta(1-42)-stimulated microglial cells, and this inhibition was blocked by mecamylamine, a non-selective nAChR antagonist, and a-bungarotoxin, a selective alpha7 nAChR antagonist. Nicotine inhibited NADPH oxidase activation and completely blocked Ca2+ influx in fA beta(1-42)-stimulated microglia. Moreover, ATP release from fA beta(1-42)-stimulated microglia was significantly suppressed by nicotine treatment. In contrast, nicotine did not inhibit 2',3'-O-(4-benzoyl)-benzoyl ATP (BzATP)-induced Ca2+ influx, but inhibited ROS generation in BzATP-stimulated microglia, indicating an inhibitory effect of nicotine on a signaling process downstream of P2X7R. Taken together, these results suggest that the inhibitory effect of nicotine on ROS production in fA beta(1-42)-stimulated microglia is mediated by indirect blockage of ATP release and by directly altering the signaling process downstream from P2X7R.

Bivalirudin: a new promising direct antithrombin.

The deadliest manifestations of ischemic heart disease are initiated and propagated by intra-coronary thrombin generation. Thrombin is resistant to inactivation by heparin when it is bound to fibrin, fibrin degradation products or subendothelial collagen. Recognition of these limitations has led to development of a new class of antithrombin agents which directly target the active sites on the surface of thrombin molecule and are therefore designated as direct antithrombins. These agents do not need mediation of antithrombin III for their action and are not inhibited by platelet factor 4. This report focuses on bivalirudin, a new agent of promising impact on both interventional as well as non-interventional cardiology. It is a short acting anticoagulant which bivalently and directly inhibits thrombin (coagulation factor II). It binds the active (catalytic) site and the fibrinogen-binding site (exosite I). This provides high affinity and specificity for thrombin. Slow cleavage at the Arg3-Pro4 bond results in recovery of thrombin activity after discontinuation of bivalirudin. Bivalirudin inhibits both protease activated receptor 1 and 4 (PAR 1 and PAR 4) thereby effectively inhibiting acute thrombin mediated platelet aggregation. Clinical efficacy has been assessed and proved in over 20 published patient series focussing on patients with acute coronary syndrome with or without myocardial infarction, patients undergoing percutaneous coronary interventions, patients receiving various adjunctive anti-platelet medications, patients with heparin induced thrombocytopenia or patients undergoing cardiac surgery. In contrast to the well established unfractionated heparin, bivalirudin lacks the risk of heparin induced thrombocytopenia. It shows a tendency to lower bleeding risks without reduction of efficacy when compared with the two-pronged treatment with unfractionated heparin and glycoprotein IIb/IIIa inhibitors.

ATP released from beta-amyloid-stimulated microglia induces reactive oxygen species production in an autocrine fashion

Present study demonstrated that fibrillar beta-amyloid peptide (fAbeta(1-42)) induced ATP release, which in turn activated NADPH oxidase via the P2X(7) receptor (P2X(7)R). Reactive oxygen species (ROS) production in fAbeta(1-42)-treated microglia appeared to require Ca2+ influx from extracellular sources, because ROS generation was abolished to control levels in the absence of extracellular Ca2+. Considering previous observation of superoxide generation by Ca2+ influx through P2X(7)R in microglia, we hypothesized that ROS production in fAbeta-stimulated microglia might be mediated by ATP released from the microglia. We therefore examined whether fAbeta(1-42)-induced Ca2+ influx was mediated through P2X(7)R activation. In serial experiments, we found that microglial pretreatment with the P2X(7)R antagonists Pyridoxal-phosphate-6-azophenyl-2',4'- disulfonate (100 micrometer) or oxidized ATP (100 micrometer) inhibited fAbeta-induced Ca2+ influx and reduced ROS generation to basal levels. Furthermore, ATP efflux from fAbeta(1-42)-stimulated microglia was observed, and apyrase treatment decreased the generation of ROS. These findings provide conclusive evidence that fAbeta-stimulated ROS generation in microglial cells is regulated by ATP released from the microglia in an autocrine manner.

Activation of neural cholecystokinin-1 receptors induces relaxation of the isolated rat duodenum which is reduced by nitric oxide synthase inhibitors

Cholecystokinin (CCK) influences gastrointestinal motility, by acting on central and peripheral receptors. The aim of the present study was to determine whether CCK has any effect on isolated duodenum longitudinal muscle activity and to characterize the mechanisms involved. Isolated segments of the rat proximal duodenum were mounted for the recording of isometric contractions of longitudinal muscle in the presence of atropine and guanethidine. CCK-8S (EC50: 39; 95 percent CI: 4.1-152 nM) and cerulein (EC50: 58; 95 percent CI: 18-281 nM) induced a concentration-dependent and tetrodotoxin-sensitive relaxation. Nomeganitro-L-arginine (L-NOARG) reduced CCK-8S- and cerulein-induced relaxation (IC50: 5.2; 95 percent CI: 2.5-18 æM) in a concentration-dependent manner. The magnitude of 300 nM CCK-8S-induced relaxation was reduced by 100 æM L-NOARG from 73 ± 5.1 to 19 ± 3.5 percent in an L-arginine but not D-arginine preventable manner. The CCK-1 receptor antagonists proglumide, lorglumide and devazepide, but not the CCK-2 receptor antagonist L-365,260, antagonized CCK-8S-induced relaxation in a concentration-dependent manner. These findings suggest that CCK-8S and cerulein activate intrinsic nitrergic nerves acting on CCK-1 receptors in order to cause relaxation of the rat duodenum longitudinal muscle.

Hemopressin: a novel bioactive peptide derived from the alpha1-chain of hemoglobin

Hemopressin (PVNFKFLSH), a novel bioactive peptide derived from the alpha1-chain of hemoglobin, was originally isolated from rat brain homogenates. Hemopressin causes hypotension in anesthetized rats and is metabolized in vivo and in vitro by endopeptidase 24.15 (EP24.15), neurolysin (EP24.16), and angiotensin-converting enzyme (ACE). Hemopressin also exerts an antinociceptive action in experimental inflammatory hyperalgesia induced by carrageenin or bradykinin via a mechanism that is independent of opioids. These findings suggest that this peptide may have important regulatory physiological actions in vivo.

A comparative study on the effect of BCG-PSN and thymopeptides on T-lymphocyte subsets of normal and immunosuppressed mice / 华中科技大学学报（医学）（英德文版）

To compare the effects of polysaccharide nucleic acid fraction of bacillus calmette guerin (BCG-PSN) and thymopeptides on T-lymphocytes of normal and immunosuppressed mice, CD4+ and CD8+ T-lymphocyte subsets of single nucleic cell in thymus, spleen and peripheral blood were detected successively by flow cytometry after application of BCG-PSN and thymopeptides. Meanwhile, CD4+/CD8+ ratio was also calculated. The results showed that both BCG-PSN and thymopeptides could decrease the proportion of CD4+ CD8+ T-lymphocyte subsets in the thymus, at the same time increase CD4+ T-lymphocyte, CD8+ T-lymphocyte proportion in the three tissues. The fluctuation in amplitude was greater in thymopeptides group than that in BCG-PSN group. It is concluded that acting location of thymopeptides is in thymus, its stimulating action is stronger than that of BCG-PSN, while BCG-PSN not only accelerates the differentiation in thymus, but also has some direct stimulation to peripheral CD4+ T-lymphocytes, and can maintain CD4+/CD8+ ratio within normal range. So, BCG-PSN is safer.

PTTH--a potential growth activator in silkworm, Bombyx mori L. for enhancing silk production.

In silkworm, prothoracicotropic hormone (PTTH), directly or indirectly controls silk production and spinning activity along with juvenile hormone (JH). An effort was made to exploit the potential of PTTH by indirectly activating silk gland for increasing silk productivity using short chain synthetic analogues of PTTH. The analogy in action was also established using PTTH extracted from the silkmoth. Different doses of 42 synthetic PTTH analogues, viz., 2.5, 5, 10 and 20ppm and 3.3 mg/ml of PTTH extracted from silkmoth heads were administered orally to V instar silkworm larvae (Race:KAxNB4D2 and PMxNB4D2) at 0-144 hr at an interval of 24 hr. The analysed data showed an improvement of about 14 - 23% in KA x NB4D2 and about 10-14% in PMxNB4D2 in respect of cocoon shell weight on administration of some of the synthetic PTTH analogues. The PTTH extracted from the adult brain also showed similar effect. The structural analogy of synthetic PTTHs (which improved the shell weight) with original PTTH and its probable mode of action in silkworm are discussed.

Anti-oxidative neuroprotection by estrogens in mouse cortical cultures

Estrogen replacement therapy in postmenopausal women may reduce the risk of Alzheimer's disease, possibly by ameliorating neuronal degeneration. In the present study, we examined the neuroprotective spectrum of estrogen against excitotoxicity, oxidative stress, and serum-deprivation-induced apoptosis of neurons in mouse cortical cultures. 17beta-estradiol as well as 17alpha-estradiol and estrone attenuated oxidative neuronal death induced by 24 hr exposure to 100 microM FeCl2, excitotoxic neuronal death induced by 24 hr of exposure to 30 microM N-methyl-D-aspartate (NMDA) and serum-deprivation induced neuronal apoptosis. Furthermore, estradiol attenuated neuronal death induced by Abeta25-35. However, all these neuroprotective effects were mediated by the anti-oxidative action of estrogens. When oxidative stress was blocked by an antioxidant trolox, estrogens did not show any additional protection. Addition of a specific estrogen receptor antagonist ICI182,780 did not reverse the protection offered by estrogens. These findings suggest that high concentrations of estrogen protect against various neuronal injuries mainly by its anti-oxidative effects as previously shown by Behl et al. Our results do not support the view that classical estrogen receptors mediate neuroprotection.

Anti-oxidative neuroprotection by estrogens in mouse cortical cultures

Estrogen replacement therapy in postmenopausal women may reduce the risk of Alzheimer's disease, possibly by ameliorating neuronal degeneration. In the present study, we examined the neuroprotective spectrum of estrogen against excitotoxicity, oxidative stress, and serum-deprivation-induced apoptosis of neurons in mouse cortical cultures. 17beta-estradiol as well as 17alpha-estradiol and estrone attenuated oxidative neuronal death induced by 24 hr exposure to 100 microM FeCl2, excitotoxic neuronal death induced by 24 hr of exposure to 30 microM N-methyl-D-aspartate (NMDA) and serum-deprivation induced neuronal apoptosis. Furthermore, estradiol attenuated neuronal death induced by Abeta25-35. However, all these neuroprotective effects were mediated by the anti-oxidative action of estrogens. When oxidative stress was blocked by an antioxidant trolox, estrogens did not show any additional protection. Addition of a specific estrogen receptor antagonist ICI182,780 did not reverse the protection offered by estrogens. These findings suggest that high concentrations of estrogen protect against various neuronal injuries mainly by its anti-oxidative effects as previously shown by Behl et al. Our results do not support the view that classical estrogen receptors mediate neuroprotection.