Welsh M J, Heistad D D, Abboud F M
J Clin Invest. 1978 Mar;61(3):708-13. doi: 10.1172/JCI108983.
Dopamine is present in the carotid body and has been postulated to be an inhibitory neurotransmitter. The purpose of this study was to determine the effects of dopamine on ventilation in man and to examine its mechanism of action. Dopamine (0.5-10 mug/kg per min) was infused in eight normal men at different levels of arterial chemoreceptor activity, produced by varying the inspired Po(2). During normoxia dopamine produced a small decrease in minute ventilation (Ve) and an increase in arterial Pco(2). When arterial chemoreceptors were stimulated by hypoxia, infusion of dopamine produced a marked initial depression of Ve followed by a sustained although less pronounced decrease in Ve. An increase in Pa(co) (2) and a decrease in Pao(2) were also observed. When arterial chemoreceptor activity was suppressed by hyperoxia, infusion of dopamine did not affect ventilation. Subjects also breathed a hypercarbic, hyperoxic gas mixture. The hypercarbia produces hyperventilation by stimulating central chemoreceptors, whereas the hyperoxia suppresses peripheral chemoreceptors. Dopamine did not alter ventilation while the subjects were breathing this gas mixture. These studies suggest that dopamine suppresses ventilation in man through an action on the arterial chemoreceptor reflex. These findings support the hypothesis that dopamine is an inhibitory neurotransmitter in the carotid body, and that release of dopamine may modulate the sensitivity of peripheral arterial chemoreceptors.
多巴胺存在于颈动脉体中，据推测它是一种抑制性神经递质。本研究的目的是确定多巴胺对人体通气的影响，并研究其作用机制。在八名正常男性中，通过改变吸入氧分压（Po₂）使动脉化学感受器处于不同活动水平时，以0.5 - 10微克/千克每分钟的速率输注多巴胺。在常氧状态下，多巴胺使分钟通气量（Ve）略有下降，动脉血二氧化碳分压（Pco₂）升高。当因缺氧刺激动脉化学感受器时，输注多巴胺最初使Ve显著降低，随后Ve持续下降，不过下降幅度较小。同时还观察到动脉血二氧化碳分压（Pa(co)₂）升高和动脉血氧分压（Pao₂）降低。当因高氧抑制动脉化学感受器活动时，输注多巴胺对通气无影响。受试者还呼吸高碳酸、高氧混合气体。高碳酸通过刺激中枢化学感受器产生过度通气，而高氧抑制外周化学感受器。在受试者呼吸这种混合气体时，多巴胺未改变通气。这些研究表明，多巴胺通过作用于动脉化学感受器反射来抑制人体通气。这些发现支持了以下假说：多巴胺是颈动脉体中的一种抑制性神经递质，多巴胺的释放可能调节外周动脉化学感受器的敏感性。
