电刺激猫前乙状回皮层对吻侧下丘脑温度敏感神经元放电频率和温度敏感性的影响

RESPONSES OF TEMPERATURE-SENSITIVE NEURONS IN THE ROSTRAL HYPOTHALAMUS TO STIMULATION OF ELECTRICAL GSA CORTEX OF CAT

本实验用微电极细胞外记录单个神经元放电的方法,观察了电刺激猫前乙状回皮层(运动区)对吻侧下丘脑中神经元放电频率和温度敏感性的影响。73例神经元(热敏神经元20例,冷敏神经元13例,温度不敏感神经元31例,以及E、F型神经元9例)中,有44例神经元观察了刺激时放电频率和刺激后温度敏感性的改变。有18例神经元表现出即时的或延迟的频率反应,X^2检验显示各类神经元频率反应之间的差异无意义。刺激前的两次温度敏感性检测之间的差异,各类神经元均无意义。刺激后,9例热敏神经元中有8例,10例冷敏神经元中有9例,温度敏感性有明显改变(P<0.05)。热敏神经元在刺激后,温度敏感性呈下降趋势(P<0.05),而冷敏神经元的温度敏感性则既有增强亦有减弱。温度不敏感神经元的敏感性无明显改变。实验结果提示,运动区皮层可影响吻侧下丘脑中温度敏感神经元的敏感性,主要是对热敏神经元起着阻抑性调控影响。

The effect of electrical stimulation of gyri sigmoid anterior (GSA) cortex of cat on the firing rate and thermosensitivity of temperature-sensitive neurons in the rostral hypothalamaus were studied by recording extracellularly the firing activity of single neuron. Among 73 neurons recorded (20 warm-sensitive neurons, WSN; 13 cold-sensitive neurons, CSN; 31 temperature-insensitive neurons, TIN; and 9 E type and F type neurons.), changes of firing rate during stimulation and themosensitivity after stimulation in 44 neurons recored were observed. 18 neurons showed responses of firing rate on the instant or after some delay. X^2test showed no significance between different neuron types in case of firing rate response. Student's t test pointed out that the difference between two thermosensitive tests before stimulation has no statistical significance in all neuron types. After stimulation, 8 / 9 WSN and 9 / 10 CSN showed responses of thermosensitivity. X^2test showed that the response was significant. Student's t test also pointed out that the decrease of thermosensitivity of WSN after electrical GSA cortex stimulation were significant. The result indicates that GSA cortex may affect thermosensitivity of temperature-sensitive neurons in the rostral hypothalamus and plays inhibitory role on WSN in temperature regulation mechanism.