Arimura H, Bosnjak Z J, Hoka S, Kampine J P
Department of Anesthesiology, Medical College of Wisconsin, Milwaukee 53226.
Can J Physiol Pharmacol. 1992 Jul;70(7):1021-31. doi: 10.1139/y92-141.
The effects of three catecholamines, dopamine, epinephrine, and dobutamine, on the systemic circulation, especially on systemic vascular capacitance, were studied using cardiopulmonary bypass in dogs anesthetized with pentobarbital. Venous outflow was divided into three compartments: splanchnic, renal, and other; changes in systemic blood volume (SBV) were calculated from the changes in total venous outflow. To examine the contribution of sympathetic discharge to these vascular responses, sympathetic efferent nerve activity (SENA) from the ventral ansa subclavian nerve was recorded simultaneously. Experiments were done under three conditions: control, after baroreceptor deafferentation, and after hexamethonium injection with low and high doses of each catecholamine. During control and after baroreceptor deafferentation, dopamine- and epinephrine-induced changes in SBV were less than those after hexamethonium, and not significant except with low dose epinephrine. After hexamethonium, dopamine (200 micrograms/kg), epinephrine (10 micrograms/kg), and dobutamine (100 micrograms/kg) reduced SBV by 10.6 +/- 3.4, 13.1 +/- 1.7, and 1.9 +/- 0.3 mL/kg, respectively. Splanchnic outflow increased significantly with dopamine and epinephrine after hexamethonium. High dose dopamine and epinephrine significantly suppressed SENA to 38 +/- 9 and 15 +/- 6% of baseline, respectively. Low dose dopamine decreased arterial pressure and SENA. This suppression in SENA was attenuated but still observed after baroreceptor deafferentation. Dobutamine reduced SBV, but had no effect on SENA. These results suggest that dopamine and epinephrine primarily decrease SBV by venoconstriction in the splanchnic region, however, these effects are greatly modified by basal sympathetic discharge and changes in SENA and vascular tone.
使用戊巴比妥麻醉的犬进行体外循环，研究了三种儿茶酚胺（多巴胺、肾上腺素和多巴酚丁胺）对体循环，尤其是对体循环血管容量的影响。静脉流出被分为三个部分：内脏、肾脏和其他；根据总静脉流出量的变化计算体循环血量（SBV）的变化。为了研究交感神经放电对这些血管反应的作用，同时记录了来自锁骨下神经腹袢的交感传出神经活动（SENA）。实验在三种条件下进行：对照、压力感受器去传入后以及注射六甲铵后给予低剂量和高剂量的每种儿茶酚胺。在对照和压力感受器去传入后，多巴胺和肾上腺素引起的SBV变化小于六甲铵给药后，除低剂量肾上腺素外均无统计学意义。六甲铵给药后，多巴胺（200微克/千克）、肾上腺素（10微克/千克）和多巴酚丁胺（100微克/千克）分别使SBV降低10.6±3.4、13.1±1.7和1.9±0.3毫升/千克。六甲铵给药后，多巴胺和肾上腺素使内脏流出量显著增加。高剂量多巴胺和肾上腺素分别将SENA显著抑制至基线的38±9%和15±6%。低剂量多巴胺降低动脉压和SENA。压力感受器去传入后，SENA的这种抑制作用减弱但仍可观察到。多巴酚丁胺降低SBV，但对SENA无影响。这些结果表明，多巴胺和肾上腺素主要通过内脏区域的静脉收缩来降低SBV，然而，这些作用会因基础交感神经放电、SENA的变化和血管张力而受到极大影响。
