乌拉坦对大鼠肼屈嗪诱导的心动过速的影响。

Effect of urethane on hydralazine-induced tachycardia in rats.

Orallo F, Fontenla J A, Loza M I, Campos M, Calleja J M

Departamento de Farmacología, Facultad de Farmacia, La Coruña, Spain.

Gen Pharmacol. 1992 Nov;23(6):1143-7. doi: 10.1016/0306-3623(92)90302-z.

Abstract

In conscious normotensive rats, hydralazine (5-10 mg kg-1 p.o.) produced a dose-related fall in systolic blood pressure, accompanied by a pronounced increase in heart rate. 2. The tachycardia induced by hydralazine (10 mg kg-1 p.o.) in conscious normotensive rats was strongly inhibited after anaesthesia with urethane (1.26 g kg-1 i.p.). 3. In anaesthetized normotensive rats, hydralazine (1 mg kg-1 i.v.) caused a fall in mean blood pressure, accompanied by irregular effects on the heart rate that consisted in a combination of initial tachycardia followed by bradycardia. 4. In pithed rats, hydralazine (1 mg kg-1 i.v.) did not affect mean arterial blood pressure but produced a significant decrease in heart rate. 5. In rat isolated atria, hydralazine (2 mM) produced a positive inotropic/negative chronotropic effect. 6. These results suggest that urethane inhibits the cardiovascular reflex that causes the tachycardia induced by hydralazine in conscious normotensive rats. For this reason, in anaesthetized normotensive rats appear the direct effect of the drug on the heart.

摘要

在清醒的血压正常大鼠中，肼屈嗪（口服5 - 10毫克/千克）可使收缩压呈剂量依赖性下降，并伴有心率显著增加。2. 在清醒的血压正常大鼠中，肼屈嗪（口服10毫克/千克）诱导的心动过速在给予乌拉坦（腹腔注射1.26克/千克）麻醉后受到强烈抑制。3. 在麻醉的血压正常大鼠中，肼屈嗪（静脉注射1毫克/千克）导致平均血压下降，并对心率产生不规则影响，表现为最初心动过速后伴有心动过缓。4. 在脊髓损毁大鼠中，肼屈嗪（静脉注射1毫克/千克）不影响平均动脉血压，但使心率显著降低。5. 在大鼠离体心房中，肼屈嗪（2毫摩尔）产生正性肌力/负性变时作用。6. 这些结果表明，乌拉坦抑制了清醒血压正常大鼠中由肼屈嗪诱导心动过速的心血管反射。因此，在麻醉的血压正常大鼠中出现了药物对心脏的直接作用。