Asano T, Otsuguro K, Ohta T, Sugawara T, Ito S, Nakazato Y
Laboratory of Pharmacology, Hokkaido University, Sapporo, Japan.
Comp Biochem Physiol C Pharmacol Toxicol Endocrinol. 1995 Oct;112(2):101-8. doi: 10.1016/0742-8413(95)02001-2.
The effect of ATP on catecholamine secretion and intracellular Ca2+ concentration ([Ca2+]i) was examined using perfused adrenal glands and dispersed chromaffin cells of the guinea-pig. The application of ATP (2 to 10 mM) for 2 min caused a dose-dependent increase in catecholamine secretion from perfused adrenal glands. ADP, but neither AMP nor adenosine, was also effective in increasing catecholamine secretion, though its potency was much less than that of ATP. 3. The ATP-induced secretory response was observed even under Na(+)-deficient conditions, but was reversibly abolished by removal of extracellular Ca2+. 4. In dispersed chromaffin cells, ATP (0.5 mM) caused increases in catecholamine secretion and [Ca2+]i, both of which were abolished after the removal of extracellular Ca2+. 5. These results indicate that ATP released from adrenal chromaffin cells together with catecholamine may exert a positive feedback influence on the following exocytotic catecholamine secretion. This effect may be accomplished by increasing the entry of extracellular Ca2+, but not by mobilizing intracellular Ca2+ stores in adrenal chromaffin cells of the guinea-pig.
利用豚鼠的灌注肾上腺和分散的嗜铬细胞，研究了ATP对儿茶酚胺分泌和细胞内钙离子浓度（[Ca2+]i）的影响。应用2至10 mM的ATP 2分钟，可使灌注肾上腺的儿茶酚胺分泌呈剂量依赖性增加。ADP对增加儿茶酚胺分泌也有效，但AMP和腺苷则无效，不过其效力远低于ATP。3.即使在缺钠条件下也能观察到ATP诱导的分泌反应，但去除细胞外钙离子后该反应可逆性消失。4.在分散的嗜铬细胞中，0.5 mM的ATP可使儿茶酚胺分泌和[Ca2+]i增加，去除细胞外钙离子后二者均消失。5.这些结果表明，从肾上腺嗜铬细胞释放的ATP可能与儿茶酚胺一起对随后的儿茶酚胺胞吐分泌产生正反馈影响。这种作用可能是通过增加细胞外钙离子的内流来实现的，而不是通过动员豚鼠肾上腺嗜铬细胞内的钙离子储存来实现的。
