EFFECTS OF DOPAMINE ON SINUS RATE AND VENTRICULAR CONTRACTILE FORCE OF THE DOG HEART in vitro AND in vivo
EFFECTS OF DOPAMINE ON SINUS RATE AND VENTRICULAR CONTRACTILE FORCE OF THE DOG HEART in vitro AND in vivo
复制标题
多巴胺对犬体内外心脏窦率和心室收缩力的影响
DOI：
10.1111/j.1476-5381.1975.tb07422.x
复制
发表时间：
1975
影响因子：
7.3
通讯作者：
M. Endoh
中科院分区：
文献类型：
--
作者：
M. Endoh
1实验在犬离体乳头肌和窦房结标本上进行，这些标本用供体犬的动脉血灌注。本文用利血平、去甲丙咪嗪、可卡因和酚苄明分析了多巴胺的变时和变力作用，确定了相对变时和变力作用，并与去甲肾上腺素的结果进行了比较。2通过乳头肌和窦房结用利血平预处理动物，动脉内注射多巴胺至离体制剂中的效应降低。然而，变时性作用的影响较小，预处理利血平比变力性作用。3去甲丙咪嗪（Desmethylimipramine，简称DMM）可减弱多巴胺的变力和变时作用，增强NA和神经刺激的作用，但对多巴胺的变时作用的影响小于其变力作用。4.可可碱显著增强NA的变力和变时作用，减弱多巴胺的变力作用，但不影响其变时作用。5酚苄明增强多巴胺、NA和神经刺激的变力作用，但不影响胺类的变时作用。6.供体犬静脉注射多巴胺（1 ~ 300 μg/kg），可优先增加心室肌的收缩力，但对离体标本和在体心脏的窦性心率变化较小。NA（0.1至10 μg/kg）引起的效应与多巴胺相似。最大的变力反应，这些儿茶酚胺达到较低的剂量比变时性的。结论是，多巴胺的正性变力性和正性变时性反应部分是通过对狗心脏中β-肾上腺素受体的直接和间接刺激作用介导的。本研究结果提示，心室肌和窦房结多巴胺和NA活性的差异可能是由于心房和心室的肾上腺素能神经纤维的分布不均匀所致（Furbindness，林登& Snow，1971）。由肾上腺素能神经纤维密集支配的窦房结可能比心室肌更有效地通过神经摄取去甲肾上腺素和多巴胺，从而对外源性儿茶酚胺不太敏感。
1 Experiments were carried out on dog isolated papillary muscle and sinus node preparations perfused with arterial blood from a donor dog. The chronotropic and inotropic effects of dopamine were analysed by using reserpine, desmethylimipramine (DMI), cocaine and phenoxybenzamine, and the relative chronotropic and inotropic effects defined, the results being compared with those for noradrenaline (NA). 2 The effects of dopamine administered intra‐arterially into the isolated preparations were reduced by pretreatment of animals with reserpine both in the papillary muscle and sinus node. The chronotropic effects, however, were affected less by pretreatment with reserpine than were the inotropic effects. 3 Desmethylimipramine (DMI) reduced the inotropic and chronotropic effects of dopamine, and enhanced the effects of NA and nerve stimulation; the chronotropic effects of the amines were less affected than the inotropic effects. 4 Cocaine enhanced considerably the inotropic and chronotropic effects of NA, and decreased the inotropic but not the chronotropic effect of dopamine. 5 Phenoxybenzamine enhanced the inotropic effects of dopamine, NA and nerve stimulation, but did not affect the chronotropic effects of the amines. 6 When dopamine (1 to 300 μg/kg) was administered intravenously to the donor dog, it increased preferentially the contractile force of the ventricular myocardium with a comparatively small change of the sinus rate in the isolated preparations as well as in the heart in vivo. NA (0.1 to 10 μg/kg) caused effects similar to those of dopamine. The maximal inotropic responses to these catecholamines were reached with lower doses than the chronotropic ones. 7 It is concluded that both the positive inotropic and the positive chronotropic responses to dopamine are mediated partially by a direct and partially by an indirect stimulant effect on β‐adrenoceptors in the dog heart. The present results suggest that the difference in activity of dopamine and NA between the ventricular myocardium and the sinus node may be ascribed to the unequal innervation with adrenergic nerve fibres of the atrium and the ventricle (Furnival, Linden & Snow, 1971). The sinus node which is densely innervated by adrenergic nerve fibres may inactivate noradrenaline and dopamine more effectively than the ventricular myocardium through the uptake into the nerve and thereby be less sensitive to the exogenous catecholamines.