Castresana M R, Zhang L M, Newman W H
Department of Anesthesiology and Critical Care Medicine, Medical Center of Central Georgia, Macon, USA.
Crit Care Med. 1995 May;23(5):939-43. doi: 10.1097/00003246-199505000-00024.
Protamine has recently been shown to have a direct vasodilator action in isolated vascular tissue. As one possible mechanism for this action, it has been hypothesized that protamine might increase the response of vascular smooth muscle to the endothelium-derived relaxing factor, nitric oxide. In this study, we tested this hypothesis and examined the effect of protamine on other guanosine 3'5'-cyclic monophosphate (cGMP)- and adenosine 3'5'-cyclic monophosphate (cAMP)-dependent processes.
Prospective, repeated measures analysis of concentration-response curves.
Anesthesia research laboratory in an academic medical center.
Cultured coronary artery smooth muscle cells from pig heart.
Sodium nitroprusside was used to mimic the action of the endothelium-derived relaxing factor by stimulating the soluble guanylyl cyclase and increasing intracellular cGMP. Atrial natriuretic peptide was used to stimulate the particulate guanylyl cyclase. Isoproterenol and forskolin were used to increase intracellular cAMP. The responses to these agents were determined in the presence and absence of protamine.
In cultured vascular smooth muscle cells, sodium nitroprusside increased cGMP, the second messenger for endothelium-derived relaxing factor, in a concentration-dependent manner. In cells treated with protamine (32 to 250 micrograms/mL), we could detect no effect of protamine on basal intracellular levels of cGMP until a concentration of 250 micrograms/mL of protamine was used. At this concentration, protamine increased basal cGMP concentrations from 4.2 +/- 0.3 to 9.0 +/- 0.6 pmol/mg protein (p < .001). The response of intracellular cGMP to sodium nitroprusside in cells treated with 250 micrograms/mL or other concentrations of protamine was not different from control. Likewise, we could detect no effect of protamine on intracellular cGMP stimulated with the atrial natriuretic peptide or on cAMP stimulated with the beta-adrenergic receptor agonist, isoproterenol, or with forskolin.
These experiments show that protamine does not alter the responses of the intracellular second messengers, cGMP and cAMP, to the vasodilators sodium nitroprusside, atrial natriuretic peptide, isoproterenol, and forskolin. These results do not support the hypothesis that protamine sensitizes vascular smooth muscle cells to the endothelium-derived relaxing factor, nitric oxide.
最近研究表明鱼精蛋白在离体血管组织中具有直接的血管舒张作用。作为这一作用的一种可能机制，有人提出鱼精蛋白可能会增强血管平滑肌对内皮源性舒张因子一氧化氮的反应。在本研究中，我们验证了这一假设，并研究了鱼精蛋白对其他依赖鸟苷3',5'-环磷酸（cGMP）和腺苷3',5'-环磷酸（cAMP）的过程的影响。
浓度-反应曲线的前瞻性重复测量分析。
一所学术医疗中心的麻醉研究实验室。
猪心脏培养的冠状动脉平滑肌细胞。
硝普钠用于通过刺激可溶性鸟苷酸环化酶和增加细胞内cGMP来模拟内皮源性舒张因子的作用。心房利钠肽用于刺激颗粒性鸟苷酸环化酶。异丙肾上腺素和福斯可林用于增加细胞内cAMP。在有和没有鱼精蛋白的情况下测定对这些药物的反应。
在培养的血管平滑肌细胞中，硝普钠以浓度依赖性方式增加cGMP，cGMP是内皮源性舒张因子的第二信使。在用鱼精蛋白（32至250微克/毫升）处理的细胞中，直到使用浓度为250微克/毫升的鱼精蛋白时，我们才检测到鱼精蛋白对基础细胞内cGMP水平没有影响。在此浓度下，鱼精蛋白使基础cGMP浓度从4.2±0.3皮摩尔/毫克蛋白增加到9.0±0.6皮摩尔/毫克蛋白（p<0.001）。用250微克/毫升或其他浓度鱼精蛋白处理的细胞中，细胞内cGMP对硝普钠的反应与对照组无差异。同样，我们未检测到鱼精蛋白对心房利钠肽刺激的细胞内cGMP或β-肾上腺素能受体激动剂异丙肾上腺素或福斯可林刺激的cAMP有影响。
这些实验表明，鱼精蛋白不会改变细胞内第二信使cGMP和cAMP对血管舒张剂硝普钠、心房利钠肽、异丙肾上腺素和福斯可林的反应。这些结果不支持鱼精蛋白使血管平滑肌细胞对内皮源性舒张因子一氧化氮敏感的假设。
