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

Li Depei, He Ruirong

Department of Physiology,Institute of Basic Medicine,Hebei Medical University.Shijiazhuang 050017,Hebei

Abstract

Intracarotid administration of ET-1 (0.3mmol/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. BQ-123 (0.67nmol/kg), a selective ET_(A) blocker, completely blocked the facilitatory effects of ET-1 in 11 out of 14 units. In 10 out of 11 units, glibenclamide (3.3nmol/kg), a blocker of ATP-sensitive potassium channel, had no effect on the action of ET-1. 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.

Key words: Endothelin;Rostral ventrolateral medulla (RVLM);Area postrema;Spontaneous discharge units;BQ-123

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Citing This Article：

Li Depei, He Ruirong. Intracarotid injection of endothelin-1 facilitates the activity of rostral ventrolateral medullary neurons via area postrema in rats. Acta Physiol Sin 1999; 51 (3): (in Chinese with English abstract).