刺激中缝背核对大鼠小脑皮层下核团神经元电活动的影响

我们首次观察了电刺激大鼠中缝背核（ＤＲ）对小脑核团（ＤＣＮ）──内侧核（ＭＮ），间位核（ＩＮ）和外侧核（ＬＮ）神经元电活动的影响。结果表明：刺激ＤＲ可引起ＤＣＮ神经元的抑制、兴奋和双相（兴奋－抑制、抑制－兴奋）三种不同类型的反应，其中以抑制性反应为主（７６％－９０％）；反应的潜伏期为１０—８４ｍｓ，但大多数细胞呈现小于３０ｍｓ的短潜伏期反应；ＤＣＮ细胞的自发放电频率为５－１２０Ｈｚ，自发放电频率高的神经元群体对ＤＲ刺激的反应比率却比自发放电频率低的群体低；静脉注射５－ＨＴ２／１ｃ受体阻断剂ｍｅｔｈｙｓｅｒｇｉｄｅ可以阻断ＤＣＮ细胞对ＤＲ刺激的抑制性反应（６６．７％－８３．３％）。这些结果提示中缝－小脑５－ＨＴ能纤维传入系统可能通过对ＤＣＮ细胞电活动的调制作用参予小脑的感觉运动整合过程。

EFFECTS OF DORSAL RAPHE STIMULATION ON ACTIVITIES OF CEREBELLAR NUCLEAR NEURONS IN THE RAT

The effects of stimulating dorsal raphe nucleus (DR) on activities of three deep cerebellar nuclei (DCN) (medial, interposed and lateral nuclei) were investigated. The results were as follows: (1)Stimulation of DR elicited three types of responses, inhibition, excitation, and biphasic response (excitation-inhibition or inhibition-excitation) from DCN cells with responsive latencies ranging from 10 to 84 ms. The majority of responsive cells showed an inhibitory response (76%-90% ) with a latency less than 30 ms. (2)The spontaneous discharge frequencies of the DCN cells were 5 to 120 Hz.The cells with higher spontaneous discharge frequencies showed low responsive rates to the DR stimulation, as compared with lower firing frequency cells. (3)The depressive effect of DR stimulation could be blocked by injection of 5-HT2/1c antagonist methysergide (66.7%-83.3%). These results suggest that raphe-cerebellum serotonergic afferent fibers may be involved in the cerebellar sensorimotor integration process by exerting some modulatory effects on the DCN cell's activities.