AIM: To investigate ion channel mechanism in CNP-induced relaxation of gastric circular smooth muscle in guinea pigs.METHODS: Spontaneous contraction of gastric smooth muscle was recorded by a four -channel physiograp...AIM: To investigate ion channel mechanism in CNP-induced relaxation of gastric circular smooth muscle in guinea pigs.METHODS: Spontaneous contraction of gastric smooth muscle was recorded by a four -channel physiograph. The whole cell patch-clamp technique was used to record calciumactivated potassium currents and membrane potential in the gastric myocytes isolated by collagenase.RESULTS: C-type natriuretic peptide (CNP) markedly inhibited the spontaneous contraction in a dose-dependent manner in gastric circular smooth muscle in guinea pigs.Ly83583, an inhibitor of guanylate cyclase, weakened CNPinduced inhibition on spontaneous contraction but Zaparinast, an inhibitor of cGMP sensitive phosphoesterase,potentiated CNP-induced inhibition in gastric circular smooth muscles. The inhibitory effects of CNP on spontaneous contraction were blocked by tetrathylammonium (TEA), a nonselective potassium channel blocker. CNP hyperpolarized membrane potential from -60.0 mV±2.0 mV to -68.3 meV±3.0 mV in a single gastric myocyte. CNP increased calcium-activated potassium currents (Ik(ca)) in a dose-dependent manner in gastric circular myocytes. CNP also increased the spontaneously transient outward currents (STOCs). Ly83583 partly blocked CNP-induced increase of calcium-activated potassium currents, but Zaparinast potented the effect.CONCLUSION: CNP inhibits spontaneous contraction, and potassium channel may be involved in the process in gastric circular smooth musde of guinea pigs. CNP-induced increase of Ik(ca) is mediated by a cGMP dependent pathway.展开更多
AIM： To evaluate the effect of ANP on warm I/R injury in a porcine THVE model.METHODS： Miniature pigs （mini-pigs） weighing 16-24 kg were observed for 120 min after reperfusion following 120 min of THVE. The animal...AIM： To evaluate the effect of ANP on warm I/R injury in a porcine THVE model.METHODS： Miniature pigs （mini-pigs） weighing 16-24 kg were observed for 120 min after reperfusion following 120 min of THVE. The animals were divided into two groups. ANP （0.1 μg/kg per min） was administered to the ANP group （n = 7）, and vehicle was administered to the control group （n = 7）. Either vehicle or ANP was intravenously administered from 30 min before the THVE to the end of the experiment. Arterial blood was collected to measure AST, LDH, and TNF-α. Hepatic tissue blood flow （HTBF） was also measured. Liver specimens were harvested for p38 MAPK analysis and histological study. Those results were compared between the two groups.RESULTS： The AST and LDH levels were lower in the ANP group than in the control group; the AST levels were significantly different between the two groups （60 min： 568.7 ± 113.3 vs 321.6 ± 60.1, P = 0.038 〈 0.05, 120 rain： 673.6± 148.2 vs 281.1±44.8, P = 0.004 〈 0.01）. No significant difference was observed in the TNF-α levels between the two groups. HTBF was higher in the ANP group, but the difference was not significant. A significantly higher level of phosphorylated p38 MAPK was observed in the ANP group compared to the control group （0min： 2.92± 1.1 vs 6.38 ±1.1,,P= 0.011 〈 0.05）.Histological tissue damage was milder in the ANP group than in the control group.CONCLUSION： Our results show that ANP has a protective role in I/R injury with p38 MAPK activation in a porcine THVE model.展开更多
Radioimmunoassays were used to measure the concentration changes of plasma endothelin(ET) and atrial natriuretic peptide(ANP) during the onset and after termination of paroxysmal supraventricular tachycardia(SVT). 30 ...Radioimmunoassays were used to measure the concentration changes of plasma endothelin(ET) and atrial natriuretic peptide(ANP) during the onset and after termination of paroxysmal supraventricular tachycardia(SVT). 30 cases were reviewed and compansons with 42 normal subjects were made. There are very significant differences(P<0.0001) in the concentration changes of both plasma ET and ANP during the onset and 30 minutes after the termination of SVT. During the onset period of SVT. the plasma ET and ANP were markedly elevated and 30 minutes after its termination they were lowered significantly, but their concentrations were still 2-fold higher than ihose of the control group. As the biological effects of ANP and ET are antagonistic to each other. their parallel elevation and lowering of plasma concentrations during and.after the termination of SVT reveal that these 2 hormones parucipate in the pathophysiological process of SVT. This phenomenon is possibly one of the homeostatic regulatory functions in the organism.展开更多
基金the National Natural Science Foundation of China, No.30160028
文摘AIM: To investigate ion channel mechanism in CNP-induced relaxation of gastric circular smooth muscle in guinea pigs.METHODS: Spontaneous contraction of gastric smooth muscle was recorded by a four -channel physiograph. The whole cell patch-clamp technique was used to record calciumactivated potassium currents and membrane potential in the gastric myocytes isolated by collagenase.RESULTS: C-type natriuretic peptide (CNP) markedly inhibited the spontaneous contraction in a dose-dependent manner in gastric circular smooth muscle in guinea pigs.Ly83583, an inhibitor of guanylate cyclase, weakened CNPinduced inhibition on spontaneous contraction but Zaparinast, an inhibitor of cGMP sensitive phosphoesterase,potentiated CNP-induced inhibition in gastric circular smooth muscles. The inhibitory effects of CNP on spontaneous contraction were blocked by tetrathylammonium (TEA), a nonselective potassium channel blocker. CNP hyperpolarized membrane potential from -60.0 mV±2.0 mV to -68.3 meV±3.0 mV in a single gastric myocyte. CNP increased calcium-activated potassium currents (Ik(ca)) in a dose-dependent manner in gastric circular myocytes. CNP also increased the spontaneously transient outward currents (STOCs). Ly83583 partly blocked CNP-induced increase of calcium-activated potassium currents, but Zaparinast potented the effect.CONCLUSION: CNP inhibits spontaneous contraction, and potassium channel may be involved in the process in gastric circular smooth musde of guinea pigs. CNP-induced increase of Ik(ca) is mediated by a cGMP dependent pathway.
文摘AIM： To evaluate the effect of ANP on warm I/R injury in a porcine THVE model.METHODS： Miniature pigs （mini-pigs） weighing 16-24 kg were observed for 120 min after reperfusion following 120 min of THVE. The animals were divided into two groups. ANP （0.1 μg/kg per min） was administered to the ANP group （n = 7）, and vehicle was administered to the control group （n = 7）. Either vehicle or ANP was intravenously administered from 30 min before the THVE to the end of the experiment. Arterial blood was collected to measure AST, LDH, and TNF-α. Hepatic tissue blood flow （HTBF） was also measured. Liver specimens were harvested for p38 MAPK analysis and histological study. Those results were compared between the two groups.RESULTS： The AST and LDH levels were lower in the ANP group than in the control group; the AST levels were significantly different between the two groups （60 min： 568.7 ± 113.3 vs 321.6 ± 60.1, P = 0.038 〈 0.05, 120 rain： 673.6± 148.2 vs 281.1±44.8, P = 0.004 〈 0.01）. No significant difference was observed in the TNF-α levels between the two groups. HTBF was higher in the ANP group, but the difference was not significant. A significantly higher level of phosphorylated p38 MAPK was observed in the ANP group compared to the control group （0min： 2.92± 1.1 vs 6.38 ±1.1,,P= 0.011 〈 0.05）.Histological tissue damage was milder in the ANP group than in the control group.CONCLUSION： Our results show that ANP has a protective role in I/R injury with p38 MAPK activation in a porcine THVE model.
文摘Radioimmunoassays were used to measure the concentration changes of plasma endothelin(ET) and atrial natriuretic peptide(ANP) during the onset and after termination of paroxysmal supraventricular tachycardia(SVT). 30 cases were reviewed and compansons with 42 normal subjects were made. There are very significant differences(P<0.0001) in the concentration changes of both plasma ET and ANP during the onset and 30 minutes after the termination of SVT. During the onset period of SVT. the plasma ET and ANP were markedly elevated and 30 minutes after its termination they were lowered significantly, but their concentrations were still 2-fold higher than ihose of the control group. As the biological effects of ANP and ET are antagonistic to each other. their parallel elevation and lowering of plasma concentrations during and.after the termination of SVT reveal that these 2 hormones parucipate in the pathophysiological process of SVT. This phenomenon is possibly one of the homeostatic regulatory functions in the organism.
