Haddad E B, Rousell J, Barnes P J
Department of Thoracic Medicine, National Heart and Lung Institute, London, UK.
Eur J Pharmacol. 1995 Aug 15;290(3):201-5. doi: 10.1016/0922-4106(95)00072-0.
We have investigated the rate and the functional responsiveness of the newly synthesised M2 muscarinic receptors in HEL 299 cells following propylbenzilylcholine mustard treatment at 37 degrees C. Propylbenzilylcholine mustard induced a dose-dependent loss of the hydrophilic ligand [3H]N-methylscopolamine binding sites with 80% inactivation at 0.1 microM. The rate of muscarinic receptor synthesis in these cells, estimated from wash-out experiments following propylbenzilylcholine mustard treatment, was very slow and returned to control values after 36 h of propylbenzilylcholine mustard removal. The recovery of muscarinic receptors was blocked by the cycloheximide pre-treatment, indicating the synthetic pathway for the new receptors. In control cells as well as in cells treated with propylbenzilylcholine mustard and allowed to recover for 12 h, carbachol still inhibited forskolin-induced cAMP accumulation. These results show that (i) the rate of M2 muscarinic receptor synthesis is slow (ii) the recovery of receptors is mainly through increased synthesis and (iii) the newly synthesised receptors retain their full functional activity.
我们研究了在37℃下用丙基苯甲酰胆碱芥子碱处理后，HEL 299细胞中新合成的M2毒蕈碱受体的速率和功能反应性。丙基苯甲酰胆碱芥子碱导致亲水性配体[3H]N-甲基东莨菪碱结合位点呈剂量依赖性丧失，在0.1 microM时80%失活。根据丙基苯甲酰胆碱芥子碱处理后的洗脱实验估计，这些细胞中毒蕈碱受体的合成速率非常缓慢，在去除丙基苯甲酰胆碱芥子碱36小时后恢复到对照值。毒蕈碱受体的恢复被环己酰亚胺预处理阻断，这表明了新受体的合成途径。在对照细胞以及用丙基苯甲酰胆碱芥子碱处理并恢复12小时的细胞中，卡巴胆碱仍抑制福斯可林诱导的环磷酸腺苷（cAMP）积累。这些结果表明：（i）M2毒蕈碱受体的合成速率缓慢；（ii）受体的恢复主要通过合成增加；（iii）新合成的受体保留其全部功能活性。
