Hiram Y, Nir A, Greenberg A, Zinder O
Biophys J. 1984 Apr;45(4):651-8. doi: 10.1016/S0006-3495(84)84206-X.
Temperature effects on the stimulus-secretion coupling process was studied by inducing release of catecholamines (CA) from isolated chromaffin cells of the bovine adrenal medulla. Use was made of three different secretagogues: acetylcholine (ACH), high potassium concentration, and the calcium ionophore A23187, at various incubation temperatures. The latter two agents induced a monotonic increase in secretion with rise in temperature, suggesting different regions of the dependence of total release on temperature. The ACH-induced secretion was, however, markedly different and exhibited a maximal release at 30 degrees C. Kinetic experiments using ACH stimulus revealed that this maximum is produced by different temperature dependence in the stages of activation and desensitization. A proposed model for the total release process yields temperature-dependent parameters that can be divided into three regions of initial rates of secretory activity corresponding to the above independent findings using high K+ concentration and the calcium ionophore. The transitions between the various regions indicate possible transitions in the physical properties of the plasma and secretory granule membranes. Elucidation of the interaction between the membranes is of primary importance in the determining mechanism of CA secretion from the isolated adrenal medulla cell.
通过诱导牛肾上腺髓质分离嗜铬细胞释放儿茶酚胺（CA），研究了温度对刺激 - 分泌偶联过程的影响。在不同的孵育温度下，使用了三种不同的促分泌剂：乙酰胆碱（ACH）、高钾浓度和钙离子载体A23187。后两种试剂随着温度升高诱导分泌呈单调增加，表明总释放对温度的依赖性存在不同区域。然而，ACH诱导的分泌明显不同，在30℃时表现出最大释放。使用ACH刺激的动力学实验表明，这种最大值是由激活和脱敏阶段不同的温度依赖性产生的。一个关于总释放过程的模型产生了与温度相关的参数，这些参数可分为三个对应于上述使用高K +浓度和钙离子载体的独立发现的分泌活动初始速率区域。不同区域之间的转变表明血浆和分泌颗粒膜物理性质可能发生转变。阐明膜之间的相互作用对于确定分离的肾上腺髓质细胞中CA分泌的机制至关重要。
