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.
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 GABA(A) 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 GABA(A) 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 GABA(B) 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 GABA(A) receptor.
He
De-Fu
DF
Department of Environmental Science and Brain Science Research Center, East China Normal University, Shanghai 200062, China. defuhe@citiz.net
Chen
Fu-Jun
FJ
Zhou
Shao-Ci
SC
D000161:Acoustic Stimulation; D000679:Amygdala / Q000502:physiology*; D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D002540:Cerebral Cortex / Q000502:physiology*; D004558:Electric Stimulation; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D007478:Iontophoresis / Q000379:methods; D008297:Male; D008839:Microelectrodes; D009474:Neurons / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018755:GABA Agonists; D018756:GABA Antagonists; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D001418:Baclofen; D001640:Bicuculline