Asakura W, Ohta H, Matsumoto K, Imamura L, Watanabe H, Matsuda H
Research Institute for Wakan-Yaku (Oriental Medicines), Toyama Medical and Pharmaceutical University, Japan.
Nihon Shinkei Seishin Yakurigaku Zasshi. 1994 Apr;14(2):77-82.
The effect of castration on the sensitivity of dopamine (DA) receptor to low doses of apomorphine was investigated using drug discrimination task and neurophysiological recording of the firing rate of DAergic neuron in the substantia nigra pars compacta in male young Wistar rats. In the behavioral study, castration did not change the dose-response curve for apomorphine (ip) discrimination (the ED50 values in sham-operated and castrated animals were 45.2 and 47.1 micrograms/kg, respectively). In the neurophysiological study, the inhibitory effect of apomorphine (iv) on the firing rate of DAergic neuron in the substantia nigra pars compacta was significantly enhanced by castration (the ED50 values in sham-operated and castrated animals were 6.15 and 2.96 micrograms/kg, respectively). These results suggest that castration does not change post-synaptic DA receptor sensitivity, whereas it potentiates the sensitivity of pre-synaptic DA receptor to low doses of apomorphine in the substantia nigra.
利用药物辨别任务以及对雄性幼年Wistar大鼠黑质致密部多巴胺能神经元放电频率进行神经生理学记录，研究了去势对多巴胺（DA）受体对低剂量阿扑吗啡敏感性的影响。在行为学研究中，去势并未改变阿扑吗啡（腹腔注射）辨别试验的剂量-反应曲线（假手术组和去势组动物的半数有效剂量分别为45.2和47.1微克/千克）。在神经生理学研究中，去势显著增强了阿扑吗啡（静脉注射）对黑质致密部多巴胺能神经元放电频率的抑制作用（假手术组和去势组动物的半数有效剂量分别为6.15和2.96微克/千克）。这些结果表明，去势不会改变突触后DA受体的敏感性，而会增强黑质中突触前DA受体对低剂量阿扑吗啡的敏感性。
