乙酰胆碱和A23187对离体大鼠肾上腺髓质细胞肾上腺素分泌的作用

通过胆碱能激动剂乙酰胆碱及离子诱导剂A23187（以下简称激动剂）作用于分离的肾上腺髓质细胞,以引起离体细胞的刺激－分泌耦联过程,运用细胞立体形态计量法计算分泌过程中的嗜铬颗粒数目的变化,运用电镜X射线显微分析法测量分泌过程中嗜铬颗粒内钙含量的变化,并运用高 液相色谱分析法测定离体细胞在激动剂作用后的肾上腺素分泌情况,结果发现,分离的肾上腺髓质细胞嗜铬颗粒内钙含量在激动剂作用10min时有明显下降,颗粒数目在激动剂作用过程中呈缓慢下降趋势,而细胞悬液中的肾上腺素含量在激动剂作用20min以后有明显的升高,激动剂作用引起的离体肾上腺髓质的细胞分泌时颗粒内钙含量的下降早于颗粒数目减少或肾上腺素升高,提示颗粒释放的Ca^2 可能是引起细胞分泌的原因之一。

Acetylcholine and A23187 stimulate epinephrine secretion of isolated rat adrenal medulla cells in vitro

Acetylcholine and A23187, two acetylcholinergic agonists, were used to induce the stimulus secretion coupling of the isolated rat adrenal medulla cells. Morphometry of numerical density and electron probe X ray quantitative microanalysis were adopted to measure the alterations in the number and calcium content of chromaffin granules in adrenal medulla cells during the agonist treatment. Secretion of epinephrine was detected by the high performance liquid chromatography (HPLC). It was found that the Ca content of the isolated rat adrenal medulla chromaffin granules dropped significantly after a 10 min incubation with the agonists, whereas the number of chromaffin granule decreased slowly during the agonist treatment and the epinephrine concentration raised significantly after a 20 min incubation with the agonists. The decrease of granule Ca content occurred earlier than the increase of epinephrine concentration, suggesting that the calcium released from chromaffin granule may in part account for the induced cell secretion. [WT5HZ]