INHIBITORY EFFECT OF GABA ON FIRING ACTIVITY OF ROSTRAL VENTROLATERAL MEDULLARY NEURONS OF RAT IN VITRO

VernacularTitle:γ-氨基丁酸对离体大鼠延髓头端腹外侧区神经元单位放电的抑制作用
Author: XIANG-PING CHU ¹ ; PENG LI ; NING-SHAN XU
Author Information

1. 上海医科大学
Keywords: γ-aminobutyric acid; γ-aminobutyric acid receptors; urnit discharges; rostral ventrolateral medulla; brain slices of medulla
From: Acta Physiologica Sinica 1998;50(5):483-489
CountryChina
Language:Chinese
Abstract: Extracellular single-unit discharges were obtained from 106 spontaneously active neurons in the region of the rostral ventrolateral medulla (RVLM) by glass microelectrode from 73 brain slices of Sprague-Dawley rats. Exogenous γ-aminobutyric acid (GABA, 0.1 ～ 3.0 mmol/L) inhibited the electrical activity of 84 out of 106 RVLM neurons dose-dependently. The inhibitory effect of GABA could be blocked by GABAA with BMI or PTX alone, the firing rates of most of the RVLM neurons were significantly increased. In 41 neurons responding to GABA, baclofen (0.1 ～ 3.0 μmol/L), a GABAB receptor selective agonist, inhibited the discharges of 33 of the neurons dose-dependently. GABAB receptor antagonist CGP35348 ( n = 13) blocked the inhibition due to baclofen ( n = 21). After perfused with CGP35348 alone, the firing rates of most of the RVLM neurons were significantly increased. Taken together, the inhibition of GABA on RVLM neurons is mediated through either GABAA or GABAB receptors and some intrinsic GABA neurons exert tonic inhibition activity.