CORRELATION BETWEEN CATECHOLAMINE SECRETION FROM BOVINE ISOLATED CHROMAFFIN CELLS AND [3H]‐OUABAIN BINDING TO PLASMA MEMBRANES
CORRELATION BETWEEN CATECHOLAMINE SECRETION FROM BOVINE ISOLATED CHROMAFFIN CELLS AND [3H]‐OUABAIN BINDING TO PLASMA MEMBRANES
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牛分离嗜铬细胞的儿茶酚胺分泌与 [3H]-哇巴因与质膜结合之间的相关性
DOI：
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发表时间：
1981
影响因子：
7.3
通讯作者：
Antonio G. García
中科院分区：
文献类型：
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作者：
D. Aunis;Antonio G. García
1在牛肾上腺髓质细胞悬液中研究了哇巴因、醋酸氯地孕酮（CMA）、酚苄明（Pbz）和钒酸盐（vanadate）等4种已知抑制Na+、K+依赖的Mg ~（2+）激活的腺苷三磷酸酶（ATP酶）活性的药物引起的儿茶酚胺（CA）分泌。2乙酰胆碱（ACh）引起悬浮在27°C氧合Krebs-碳酸氢盐溶液中的分离细胞的基础CA分泌增加5倍。通过Ca 2+剥夺或六烃季铵拮抗分泌，表明细胞的良好功能活力。3哇巴因（10− 7至10− 4 m）引起CA从细胞悬液中逐渐释放，呈剂量依赖性。对2小时分泌反应时间进程的研究允许在所有研究剂量下分离分泌反应中的两种组分：缓慢的初始组分（0.011 pg/min CA）和第二种较快组分（0.032 pg/min CA）。4 CMA诱发了明确的CA分泌反应。CMA的ED 50为10− 4 m，而哇巴因为3 × 10− 6 m。Pbz和钒酸盐不诱导CA释放。5 [3 H]-哇巴因被吸收并通过非饱和结合过程与完整的分离细胞结合。然而，在牛肾上腺髓质的半纯化质膜中，观察到饱和特异性[3 H]-哇巴因结合过程，KD为8.1 nm。与膜的结合是ATP依赖性的，并被K+拮抗。6 [3 H]-哇巴因与膜的特异性结合被哇巴因和CMA拮抗，但不被Pbz或钒酸盐拮抗;哇巴因和CMA的ID 50分别为10 - 6和10 - 5 m。7哇巴因以剂量依赖性方式部分抑制半纯化质膜的Na+，K+-Mg 2 + ATP酶活性。8结果表明，已知抑制ATP酶活性的不同药物取代[3 H]-哇巴因与肾上腺髓质质膜结合的能力与它们从分离的嗜铬细胞中引起CA分泌反应的能力之间存在良好的相关性。这些数据还表明，哇巴因的CA分泌的影响可能不是由于简单地抑制Na+泵和随后的离子重新分布在质膜;第二种机制也可能参与。
1 Secretion of catecholamines (CA) evoked by ouabain, chlormadinone acetate (CMA), phenoxybenzamine (Pbz) and vanadate, four agents known to inhibit Na+, K+‐dependent Mg2+‐activated adenosine triphosphatase (ATPase) activity has been studied in suspensions of bovine isolated adrenal medullary cells. 2 Acetylcholine (ACh) evoked a 5 fold increase of the basal CA secretion from isolated cells suspended in oxygenated Krebs‐bicarbonate solution kept at 27°C. Secretion was antagonized by Ca2+‐deprivation or hexamethonium, indicating good functional viability of the cells. 3 Ouabain (10−7to 10−4m) evoked a progressive, dose‐dependent release of CA from cell suspensions. Study of the time course of the secretory response for 2h allowed the separation of two components in the secretory response at all doses studied: a slow initial component (0.011 pg/min CA) and a second faster component (0.032 pg/min CA). 4 CMA evoked a clear‐cut CA secretory response. The ED50for CMA was 10−4m, as compared to 3 × 10−6m for ouabain. Pbz and vanadate did not induce CA release. 5 [3H]‐ouabain was taken up and bound to intact isolated cells by a non‐saturable binding process. However, in semi‐purified plasma membranes from bovine adrenal medulla a saturable specific [3H]‐ouabain binding process was observed with a KD of 8.1 nm. Binding to the membranes was ATP‐dependent and antagonized by K+. 6 [3H]‐ouabain specific binding to membranes was antagonized by ouabain and CMA, but not by Pbz or vanadate; the ID50 for ouabain and CMA were 10−6and 10−5m respectively. 7 Ouabain partially inhibited, in a dose‐dependent manner, Na+, K+‐Mg2+ATPase activity of the semi‐purified plasma membranes. 8 The results demonstrate a good correlation between the ability of different drugs, known to inhibit ATPase activity, to displace [3H]‐ouabain binding to adreno—medullary plasma membranes and their capacity to evoke a CA secretory response from isolated chromaffin cells. The data also suggest that the CA secretory effects of ouabain may not be due simply to inhibition of the Na+pump and the subsequent ionic redistribution across the plasma membrane; a second mechanism may also be involved.