内皮素通过最后区易化大鼠延髓腹外侧头端区神经元活动

在３５只切断双侧缓冲神经、用氨基甲酸乙酯－α氯醛糖混合麻醉的Ｓｐｒａｇｕｅ－Ｄａｗｌｅｙ大鼠,应用细胞外记录的电生理学方法,由ＲＭ－６０００型多道生理记录仪和ＷＳ－６８２Ｇ热阵记录器（频响范围０～２．８ｋＨｚ）同步记录血压、心率和单位神经元放电,观察颈动脉注射内皮素对８７个延髓腹是头端区（ＲＶＬＭ）自发放电神经元活动的影响,所得结果如下;（１）颈动脉注射ＥＴ－１（０．３ｎｍｏｌ／ｋｇ）时３６个单位

Intracarotid injection of endothelin-1 facilitates the activity of rostral ventrolateral medullary neurons via area postrema in rats

To observe the effect of intracarotid administration of endothelin (ET-1) on electrical activity of neurons within rostral ventrolateral medulla (RVLM) region, 87 spontaneous active units were extracellularly recorded in 35 Sprague-Dawley rats with sino-aortic denervation. The results obtained are as follows. (1) Intracarotid administration of ET-1 (0.3 nmol/kg) increased the discharge firing rate from 17.8 +/- 1.5 to 20.9 +/- 1.4 spikes/s (P < 0.01) in 30 out of 36 RVLM neurons, while blood pressure and heart rate had no significant change. (2) BQ-123 (0.67 nmol/kg), a selective ETA blocker, completely blocked the facilitatory effects of ET-1 in 11 out of 14 units. (3) In 10 out of 11 units, glibenclamide (3.3 nmol/kg), a blocker of ATP-sensitive potassium channel, had no effect on the action of ET-1. (4) After ablation of area postrema (AP), the facilitatory action of intracarotid administration of ET-1 on 19 units of RVLM was abolished, while in 7 units of sham ablation animals the response of neurons to ET-1 remained unchanged. Taken together, intracarotid-administered ET-1 may act on the ETA receptors in neurons of AP, thereby resulting in the facilitating effect on RVLM neurons through the efferent projection of AP.