Brudzynski S M, McLachlan R S, Bihari F, Girvin J P
Department of Clinical Neurological Sciences, University Hospital, London, Ontario, Canada.
Brain Res Bull. 1991 Jun;26(6):929-34. doi: 10.1016/0361-9230(91)90259-m.
Behavioural effects of carbachol given into the hypothalamic/preoptic area have been demonstrated but there is a paucity of information about the response of single neurons to carbachol. The aim of the present study was to determine the response of spontaneously firing neurons in the rat hypothalamic/preoptic area to application of carbachol by iontophoresis or by pressure injection in a dose and volume comparable with that used in behavioural studies. Extracellular single unit recordings showed a significant decrease in mean firing rate in 82% of neurons responding to iontophoretic carbachol and in 75.5% of neurons responding to carbachol injected about 600 microns away. An increase in firing rate occurred in only 15 and 17.6% of neurons, respectively. Application of saline did not alter the mean firing rate while application of glutamate into the same areas or ejection into the vicinity of the same neurons caused an increase in mean firing rate in 94% of responding neurons. The results indicate that a decrease in mean firing rate is the predominant neuronal response to carbachol in the anteromedial hypothalamic/preoptic area of the rat and we suggest that this decrease may be associated with behavioural responses to carbachol.
已证实将卡巴胆碱注入下丘脑/视前区会产生行为效应，但关于单个神经元对卡巴胆碱的反应的信息却很少。本研究的目的是通过离子电泳或压力注射，以与行为学研究中使用的剂量和体积相当的方式，来确定大鼠下丘脑/视前区自发放电神经元对卡巴胆碱应用的反应。细胞外单单位记录显示，在对离子电泳给予卡巴胆碱作出反应的神经元中，82%的神经元平均放电率显著降低；在对约600微米外注射卡巴胆碱作出反应的神经元中，75.5%的神经元平均放电率显著降低。放电率增加的神经元分别仅占15%和17.6%。应用生理盐水不会改变平均放电率，而在相同区域应用谷氨酸或向相同神经元附近喷射谷氨酸会使94%的反应神经元平均放电率增加。结果表明，平均放电率降低是大鼠下丘脑前内侧/视前区神经元对卡巴胆碱的主要反应，我们认为这种降低可能与对卡巴胆碱的行为反应有关。
