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环核苷酸作为第二信使参与体内许多生理功能的调节。近年来,一些工作证明,交感神经可以通过心肌β受体,促使 cAMP 升高,以提高心肌兴奋性;而迷走神经则可以通过心肌胆硷能受体,增加细胞内cGMP,对抗 cAMP 的作用,从而抑制心肌兴奋性。脑内也广泛分布着环核苷酸及其代谢酶。一些工作证明,环核苷酸在中枢心血管活动的调节中也起着重要作用。给麻醉猫注射 db-cAMP,可以明显提高交感神经兴奋性,使血压升高。最近 Clipsham 等(1980)利用清醒猫进行实验,发现向第三脑室注射 papaverine 和氨茶硷,抑制磷酸二酯酶对环核苷酸的降解作用,可以升高血压,加快心率。而使用磷酸二酯酶激动剂 imidazole-4′-acetic acid
Cyclic nucleotides, as second messengers, are involved in the regulation of many physiological functions in the body. In recent years, some work proves that sympathetic nerve can increase cAMP through myocardial β receptor to increase cardiac excitability; while vagus nerve can increase intracellular cGMP and antagonize the effect of cAMP through the cardiac cholinergic receptor Inhibit myocardial excitability. Circulating nucleotides and their metabolic enzymes are also widely distributed in the brain. Some work has shown that cyclic nucleotides also play an important role in the regulation of central cardiovascular activity. Injection of anesthesia cats db-cAMP, can significantly improve sympathetic excitability, so that blood pressure. Recently, Clipsham et al. (1980) used awake cats to experiment and found that injection of papaverine and aminophylline into the third ventricle inhibited the degradation of cyclic nucleotides by phosphodiesterase, which can increase blood pressure and speed up heart rate. Phosphodiesterase agonist imidazole-4’-acetic acid was used