Analysis of inhibitory and excitatory actions of dopamine on chemoreceptor discharges of carotid body of cat in vivo.
Analysis of inhibitory and excitatory actions of dopamine on chemoreceptor discharges of carotid body of cat in vivo.
复制标题
多巴胺对猫体内颈动脉体化学感受器放电的抑制和兴奋作用分析。
DOI：
10.2170/jjphysiol.31.695
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
K. Nishi
中科院分区：
文献类型：
--
作者：
Y. Okajima;K. Nishi
记录猫在体颈动脉窦神经的化学感受器放电，并以其频率作为受体活性的指标。分析多巴胺对正常和缺血颈动脉小体化学感受器活性的影响。动脉内注射多巴胺(DA)可引起不同类型的化学感受器反应：简单抑制、先抑制后兴奋和简单兴奋，这取决于剂量和两次注射之间的时间间隔。在大剂量DA作用后，对DA的抑制反应转变为兴奋性反应。利血平(0.1 mg/kg，iv)预处理。或5-羟基多巴胺(5 mg/kg，静脉注射)将对DA的抑制性反应转化为兴奋性反应。静脉注射氟哌啶醇(0.1 mg/kg)后，对DA的抑制反应被完全阻断，DA引起的化学感受器放电呈剂量依赖性增加。颈动脉小体缺血1小时后，DA仅引起抑制性反应，可被氟哌啶醇阻断，但不产生任何兴奋性反应。结果表明，DA对可能位于神经末梢的抑制性多巴胺能受体具有自我阻断作用，DA也直接作用于球体细胞，产生化学感受器兴奋。
Chemoreceptor discharges were recorded from the carotid sinus nerve of the cat in vivo, and their frequency was used as an index of receptor activity. The effects of dopamine on chemoreceptor activity were analyzed in normal and ischemic carotid bodies. Intra-arterial injections of dopamine (DA) induced various patterns of chemoreceptor responses; simple inhibition, inhibition followed by excitation, and simple excitation, depending upon doses and the time interval between two injections. After a large dose of DA, a previous inhibitory response to DA was converted into an excitatory one. Pretreatment of the animal with reserpine (0.1 mg/kg, i.v.) or 5-hydroxydopamine (5 mg/kg, i.v.) also converted the inhibitory response to DA into the excitatory one. After haloperidol (0.1 mg/kg, i.v.), the inhibitory response to DA was completely blocked, and DA induced a dose-dependent increase in chemoreceptor discharges. After 1-hr ischemia of the carotid body, DA induced only the inhibitory response, which was blocked by haloperidol, but did not produce any excitatory responses. Results indicate that DA exerts a self-blocking action on inhibitory dopaminergic receptors which are possibly located on the nerve ending, and that DA, also acting directly on the glomus cell, would produce the chemoreceptor excitation.