Saegusa K, Furukawa Y, Chiba S
J Cardiovasc Pharmacol. 1986 May-Jun;8(3):614-20. doi: 10.1097/00005344-198605000-00026.
The effects of hydralazine (HYD) on heart rate and blood pressure in the intact dog and on atrial rate and contractile force in the isolated atrium were investigated. HYD (0.1-1 mg) injected into the sinus node artery produced double peaked positive inotropic and negative chronotropic effects in a dose-related manner. The initial positive inotropic and negative chronotropic responses were not affected by propranolol and atropine, respectively. The second positive inotropic response was inhibited by propranolol or reserpine, but it was not suppressed by imipramine or tetrodotoxin. When HYD (0.1-1 mg/kg) was administered intravenously to the donor dog, an initial increase followed by a decrease in blood pressure and an increase in heart rate were observed. In the isolated atrium, an increase in contractile force was induced. The increases of blood pressure and heart rate in the donor dog and the positive inotropic effect in the isolated atrium after HYD treatment were suppressed by reserpine. These results suggest that HYD has direct positive inotropic and negative chronotropic effects and indirect cardiac stimulating effects caused by a release of catecholamines from sympathetic nerve terminals, and that HYD-induced catecholamine release is not mediated by a tyramine-like action or via nerve excitation.
研究了肼屈嗪(HYD)对完整犬的心率和血压以及对离体心房的心房率和收缩力的影响。将HYD(0.1 - 1毫克)注入窦房结动脉会产生双相的正性肌力和负性变时作用,且呈剂量相关。最初的正性肌力和负性变时反应分别不受普萘洛尔和阿托品的影响。第二次正性肌力反应被普萘洛尔或利血平抑制,但不受丙咪嗪或河豚毒素抑制。当向供体犬静脉注射HYD(0.1 - 1毫克/千克)时,观察到血压先升高后降低,心率增加。在离体心房中,可诱导收缩力增加。利血平抑制了HYD处理后供体犬的血压和心率升高以及离体心房中的正性肌力作用。这些结果表明,HYD具有直接的正性肌力和负性变时作用以及由交感神经末梢释放儿茶酚胺引起的间接心脏刺激作用,并且HYD诱导的儿茶酚胺释放不是由酪胺样作用或通过神经兴奋介导的。