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GABA mediaties the inhibitory effect of lateral amygdaloid nucleus stimulation on the acoustic response of neurons in A Ⅰ cortex:An in vivo microiontophoretic study

He Defu, Chen Fujun, Zhou Shaoci

Department of Environmental Science and, Brain Science Research Center, East China Normal University. Shanghai 200062, China

Abstract

Experiments were performed on Sprague Dawley rats with multibarrel microelectrode technique. The effects of acoustic response of A-Ⅰ cortex neurons produced by electrical stimulation of lateral amygdaloid nucleus (LA) and the influence of GABA were observed. Experimental results showed that iontophoretic administration of GABA caused a pronounced inhibition of the electrical activity of A-Ⅰ neurons. Blockade of GABAA with bicuculline (BIC) facilitated the acoustic response. The acoustic response of A-Ⅰ neurons was inhibited when the LA was stimulated. Iontophoretic application of GABA resulted in a similar inhibitory effect as that of LA stimulation. Blockade of GABAA with bicuculline reversed the inhibitory effect of LA stimulation on the acoustic response of A-Ⅰ neurons. In contrast, application of strychnine, a glycine receptor antagonist, could not reverse the inhibitory effect of LA. Baclofen, a GABAB agonist, did not affect the acoustic response of the auditory neurons. These results indicate that GABA is the ultimate transmitter which mediates the LA stimulation-induced inhibition of the acoustic response of A-Ⅰ neurons in rats, possibly via the GABAAreceptor

Key words: Lateral amygdaloid nucleus;A-Ⅰ cortex;Acoustic response;Inhibition;GABA

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Citing This Article：

He Defu, Chen Fujun, Zhou Shaoci. GABA mediaties the inhibitory effect of lateral amygdaloid nucleus stimulation on the acoustic response of neurons in A Ⅰ cortex:An in vivo microiontophoretic study. Acta Physiol Sin 2004; 56 (3): (in Chinese with English abstract).