Furukawa Y, Akahane K, Haniuda M, Chiba S
Department of Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan.
Arch Int Pharmacodyn Ther. 1989 Nov-Dec;302:107-18.
We investigated the effects of adenosine on the positive chronotropic and inotropic responses to an endogenous catecholamine (norepinephrine), a beta 1-adrenoceptor agonist (dobutamine), an adenylate cyclase activator (forskolin), a phosphodiesterase inhibitor (3-isobutyl-1-methylxanthine, IBMX) and a calcium channel agonist (Bay k 8644) in the isolated, blood-perfused dog atrium. Each drug was injected into the sinus node artery of the isolated atrium. Adenosine infusions at low (45 or 90 nmol/min) and high (184 or 450 nmol/min) doses induced a dose-dependent decrease of sinus rate and atrial contractile force. The positive chronotropic and inotropic responses to norepinephrine, dobutamine and forskolin were dose-dependently depressed by adenosine. IBMX- and Bay k 8644-induced positive cardiac responses were also inhibited by adenosine at high doses but not at low doses. These results suggest that adenosine attenuates calcium channel-dependent as well as cyclic AMP-dependent positive chronotropic and inotropic responses to cardiostimulants in the isolated dog atrium.
我们研究了腺苷对离体、血液灌注犬心房中内源性儿茶酚胺（去甲肾上腺素）、β1肾上腺素能受体激动剂（多巴酚丁胺）、腺苷酸环化酶激活剂（福斯高林）、磷酸二酯酶抑制剂（3-异丁基-1-甲基黄嘌呤，IBMX）和钙通道激动剂（Bay k 8644）所引起的正性变时和变力反应的影响。将每种药物注入离体心房的窦房结动脉。低剂量（45或90 nmol/min）和高剂量（184或450 nmol/min）的腺苷输注均引起窦性心率和心房收缩力的剂量依赖性降低。腺苷对去甲肾上腺素、多巴酚丁胺和福斯高林的正性变时和变力反应具有剂量依赖性抑制作用。高剂量而非低剂量的腺苷也抑制了IBMX和Bay k 8644诱导的心脏正性反应。这些结果表明，腺苷减弱了离体犬心房中钙通道依赖性以及环磷酸腺苷依赖性对心脏刺激剂的正性变时和变力反应。
