MECHANISMS OF BETA-ADRENERGIC-RECEPTOR REGULATION IN CULTURED CHICK HEART-CELLS - ROLE OF CYTOSKELETON FUNCTION AND PROTEIN-SYNTHESIS
MECHANISMS OF BETA-ADRENERGIC-RECEPTOR REGULATION IN CULTURED CHICK HEART-CELLS - ROLE OF CYTOSKELETON FUNCTION AND PROTEIN-SYNTHESIS
复制标题
DOI：
10.1161/01.res.57.1.171
复制
发表时间：
1985-01-01
影响因子：
20.1
通讯作者：
KIM, DH
中科院分区：
文献类型：
--
作者：
MARSH, JD;LACHANCE, D;KIM, DH
通过研究细胞骨架干扰剂和抑制蛋白质合成对鸡胚心完整培养的心室细胞的受体特性和对异丙肾上腺素的收缩反应的影响，探讨了心脏组织调节β-肾上腺素能受体和β-肾上腺素能激动剂的生理反应的机制。完整细胞暴露于1微米异丙肾上腺素30分钟后，高亲和力丧失(Kd=4.5+-。1.5 nM)，而对1微米异丙肾上腺素的收缩反应下降至41.+-。对照16%(SD)。收缩反应在撤除激动剂后60分钟内恢复至78。+-。最初反应的11%。伴随着受体高亲和力状态的恢复，因此，在激动剂去除1h后，高亲和力受体的比例达到初始比例的72%。这种收缩反应的脱敏，以及在撤除激动剂后的恢复，明显地被细胞松弛素B预先孵育而钝化，从而使对异丙肾上腺素的收缩反应维持在77。+-。最初回复的13%。秋水仙碱(10微米)对激动剂诱导的脱敏前30分钟无影响。更长时间的激动剂暴露(1微米异丙肾上腺素作用24小时)使完整细胞对秋水仙素敏感的受体丢失到对照水平的40%。受体数目在72小时内完全恢复；这一过程可被放线菌酮完全阻断(P<；0.01)。β受体介导的收缩反应的快速脱敏和再增敏与高亲和力激动剂结合的改变有关，并且似乎受到微丝的调节。受体的下调依赖于功能微管，而激动剂去除后这些受体的恢复需要蛋白质的合成。
Mechanisms by which cardiac tissue regulates the .beta.-adrenergic receptor and physiological response to .beta.-adrenergic agonists were examined by studying the effects of cytoskeletal disrupting agents and inhibition of protein synthesis on receptor properties and contractile response to isoproterenol in intact cultured ventricular cells from embryonic chick heart. Thirty minutes of exposure of intact cells to 1 .mu.M isoproterenol produced loss of the high-affinity state (Kd = 4.5 .+-. 1.5 nM) of the receptor found in cell membranes with no loss of total receptor number, whereas there was concomitant decline in the contractile response to 1 .mu.M isoproterenol to 41 .+-. 16% (SD) of control. Contractile response recovered within 60 min of agonist removal to 78 .+-. 11% of initial response. There was concomitant recovery of the high-affinity state of the receptor, so that 1 h after agonist removal there was 72% of the initial proportion of high-affinity receptors. This desensitization of the contractile response, as well as recovery after agonist removal, was markedly blunted by preincubation with cytochalasin B so that contractile responsiveness to isoproterenol was maintained at 77 .+-. 13% of the initial response. Colchicine (10 .mu.M) was without effect on the first 30 min of agonist-induced desensitization. More prolonged agonist exposure (1 .mu.M isoproterenol for 24 h) produced colchicine-sensitive loss of receptors from intact cells to 40% of control levels. Full recovery of receptor number occurred over 72 h; this was completely blocked by cycloheximide (P < 0.01). Rapid desensitization and resensitization of the .beta.-receptor-mediated contractile response is associated with alterations in high-affinity agonist binding and appears to be modulated by microfilaments. Receptor down-regulation is dependent on functional microtubules, and recovery of these receptors after agonist removal requires protein synthesis.