甲基黄嘌呤和咪唑对豚鼠回肠经壁刺激诱发收缩的影响。

Effects of methylxanthines and imidazole on the contractions of guinea-pig ileum induced by transmural stimulation.

作者信息

Moritoki H, Morita M, Kanbe T

出版信息

Eur J Pharmacol. 1976 Jan;35(1):185-98. doi: 10.1016/0014-2999(76)90314-9.

Abstract

Methylxanthines (10(-5) to 10(-3)M) were found to increase the amplitude of contractions of guinea-pig ileum induced by transmural stimulation but to inhibit those induced by acetylcholine or histamine. The order of the abilities of methylxanthines to augment the contractile responses was theobromine greater than caffeine greater than theophylline. When the contractions were completely suppressed by reduction of the calcium content in the medium or by addition of cyclic AMP, methylxanthines restored the responses effectively, just as does addition of calcium. Methylxanthines also accelerated the release of acetylcholine from the ileum associated with stimulation. Imidazole (3 X 10(-5) to 10(-3) M) had an essentially similar effect to methylxanthines in potentiating the contractile responses and in augmenting the release of acetylcholine. The present results indicate that the potentiating effects of methylxanthines and imidazole are due to an action on the nerve terminals, not on the postsynaptic membranes or contractile elements. Therefore, it si concluded that theit potentiating actions are due to facilitation of the movement of calcium in the nerve terminals on excitation, resulting in increased release of acetylcholine, and are not due to the effect of cyclic AMP formed as a result of their inhibitory actions on phosphodiesterase.

摘要

发现甲基黄嘌呤（10⁻⁵至10⁻³M）可增加豚鼠回肠经壁刺激诱导的收缩幅度，但抑制乙酰胆碱或组胺诱导的收缩。甲基黄嘌呤增强收缩反应能力的顺序为：可可碱＞咖啡因＞茶碱。当通过降低培养基中的钙含量或添加环磷酸腺苷使收缩完全受到抑制时，甲基黄嘌呤能像添加钙一样有效地恢复反应。甲基黄嘌呤还能加速与刺激相关的回肠乙酰胆碱释放。咪唑（3×10⁻⁵至10⁻³M）在增强收缩反应和增加乙酰胆碱释放方面与甲基黄嘌呤具有基本相似的作用。目前的结果表明，甲基黄嘌呤和咪唑的增强作用是由于对神经末梢的作用，而非对突触后膜或收缩元件的作用。因此，得出结论，它们的增强作用是由于兴奋时促进神经末梢内钙的移动，导致乙酰胆碱释放增加，而不是由于它们对磷酸二酯酶的抑制作用所形成的环磷酸腺苷的作用。