Jones C A, Madison J M, Tom-Moy M, Brown J K
Am J Physiol. 1987 Jul;253(1 Pt 1):C97-104. doi: 10.1152/ajpcell.1987.253.1.C97.
The goal of our study was to test for an inhibitory effect of acetylcholine on adenylate cyclase activity in canine trachealis muscle. Therefore, cells were dispersed from the muscle enzymatically and lysed, and adenylate cyclase activity was assayed in a membrane suspension isolated from the lysates. Maximal beta-adrenergic stimulation, in the presence of GTP (10(-4) M), increased the activity of adenylate cyclase twofold above the activity induced by GTP alone. In the presence of GTP, acetylcholine (10(-4) M) decreased activity from 97 +/- 21 to 55 +/- 13 pmol cyclic AMP X min-1 X mg protein-1 (means +/- SE; n = 5; P less than 0.05); in the presence of GTP plus isoproterenol (10(-4) M), the acetylcholine-induced decreases were from 163 +/- 29 to 101 +/- 15 pmol cyclic AMP X min-1 X mg protein-1 (P less than 0.05). These decreases were dose dependent and they were altered by a series of cholinergic agents in a pattern consistent with a muscarinic effect. Our results suggest that one biochemical effect of vagal stimulation in the central airways of dogs may be attenuated adenylate cyclase activity in the smooth muscle.
我们研究的目的是检测乙酰胆碱对犬气管平滑肌中腺苷酸环化酶活性的抑制作用。因此，用酶法从肌肉中分散细胞并使其裂解，然后在从裂解物中分离出的膜悬液中测定腺苷酸环化酶活性。在存在GTP（10⁻⁴ M）的情况下，最大β-肾上腺素能刺激使腺苷酸环化酶的活性比单独由GTP诱导的活性增加了两倍。在存在GTP的情况下，乙酰胆碱（10⁻⁴ M）使活性从97±21降至55±13 pmol环磷酸腺苷×分钟⁻¹×毫克蛋白⁻¹（均值±标准误；n = 5；P<0.05）；在存在GTP加异丙肾上腺素（10⁻⁴ M）的情况下，乙酰胆碱诱导的活性降低从163±29降至101±15 pmol环磷酸腺苷×分钟⁻¹×毫克蛋白⁻¹（P<0.05）。这些降低是剂量依赖性的，并且一系列胆碱能药物以与毒蕈碱样作用一致的模式改变了它们。我们的结果表明，迷走神经刺激在犬中央气道中的一种生化效应可能是平滑肌中腺苷酸环化酶活性减弱。
