植物提取剂福司柯林对心房钠尿肽分泌的调节作用

Regulative effect of plant extract forskolin on atrial natriuretic peptide secretion

目的:观察从植物中提取的腺苷酸环化酶直接激活剂——福司柯林对心房钠尿肽分泌的影响及其机制。方法:实验于2004-09/2005-09在吉林省延边大学医学部基础医学院生理学与病理生理学教研部完成。取大耳白兔26只,麻醉后立即开胸取出心脏,剥离左心房后固定心房灌流装置上,并给予适宜的电刺激使其搏动。利用体外灌流搏动的家兔心房做以下实验:①待心房搏动稳定之后,经过一个对照组循环(每12min定为一个实验循环),处理福司柯林(1μmol/L)3个循环。②经过一个循环对照组之后,先处理L-型Ca2+通道阻断剂硝苯地平(1μmol/L)或蛋白激酶非选择性抑制剂stau-rosporine(1μmol/L)3个循环,在硝苯地平或staurosporine存在下再处理福司柯林追加3个循环。以上实验均采用放射免疫技术和实时测定环-磷酸腺苷方法观察福司柯林对心房搏出量、环-磷酸腺苷逸出量及心房钠尿肽分泌的影响。结果:①福司柯林(1μmol/L)明显抑制心房钠尿肽分泌(P<0.01),同时显著增加心房搏出量和环-磷酸腺苷逸出量(P<0.01);在一定范围内,环-磷酸腺苷生成越多心房钠尿肽分泌越受抑制,并呈现线性关系(Y=-5.268X+9.506,r2=0.971,P<0.001)。②硝苯地平(1μmol/L)未能改变福司柯林对心房钠尿肽分泌的抑制和促进环-磷酸腺苷的生成效应(P<0.01),但显著抑制心房搏出量(P<0.01)。③staurosporine+福司柯林明显增加环-磷酸腺苷逸出量(P<0.01)的同时显著抑制心房钠尿肽的分泌(P<0.01),但心房搏出量并没有受到环-磷酸腺苷生成增多的影响,且心房钠尿肽的分泌与staurosporine(第3个循环)相比并没有显著性差异。结论:腺苷酸环化酶直接激活剂福司柯林主要通过蛋白激酶-依赖的信号转导途径抑制心房钠尿肽分泌。

AIM： To investigate the effect of the activation of adenylyl cyclase （AC） , extracted from plants, with forskolin on atrial natriuretic peptide （ANP） secretion as well as its mechanism. METHODS： The experiment was conducted in the Department of Physiology and Pathophysiology, Basic Medical School of Yanbian University in Jilin Province from September 2004 to September 2005. Twenty-six rabbits were selected and cut open the chest under anesthetization to remove the heart, The left auricle was isolated and fixed on the atrial perfusion system, which was given proper electric stimulation for beating. The following experiments were carried out on beating rabbit ventricles of in vitro perfusion：①When beating atria was stabilized, the control cycle （12 minutes as an experimental cycle） was followed by infusion of AC activator forskoline for three cycles （1 μmol/L）. ②After one control cycle, the L type Ca^2＋ channel blocker nifedipine （1 μmol/L） or nonspecific inhibitor protein kinases staurosporine was followed by forskolin for three cycles in the presence of the prior agents. The effects of forskolin on atrial stroke volume, and the efflux of cyclic adenosine monophosphate （cAMP） as well as ANP secretion were detennined in real-time base by radioimmunoassay. RESULTS： ①Forskolin（ 1 μmol/L） obviously inhibited ANP secretion （P 〈 0.01） and remarkably increased atrial stroke volume and cAMP efflux （P 〈 0.01）. Within certain range, the more the cAMP was the more the ANP secretion was inhibited, which were in a linear relationship （Y=-5.268 X＋9.506, r^2=0.971, P〈0.001）.②Nifedipine （1 μmol/L） could not change the effect of forskolin on ANP secretion and cAMP （P 〈 0.01）, whereas it could remarkably inhibited the atrial stroke volume （P 〈 0.01）. ③Intcgrated using of stauosporine and forskolin could markedly increase the cAMP efflux （P 〈 0.01） as well as remarkably inhibit ANP secretion （P 〈 0.01）. However, the atrial stroke volume was not affected by increased eAMP, moreover, there was no significant difference between ANP secretion and staurosporine （the third cycle）. CONCLUSION： Forskolin, the activating agent of camp, inhibits atrial ANP secretion mainly by protein kinase-dependent signal transduction pathway.