[GABA mediated inhibitory effect of amygdala on the activity of medial geniculate body neurons].
On 10 New Zealand white rabbits immobilized with Flaxedil, the inhibitory effect of amygdaloid stimulation on the responses of medial geniculate body (MGB) neurons to tone bursts and the involved neurotransmitter mechanism were investigated with microiontophoresis technique. The results showed that application of GABA could cause a suppression of spontaneous activity of MGB neurons while GABAA antagonist bicuculline had an opposite effect. Iontophoretic injection of GABA gave an inhibitory effect on MGB neurons similar to that caused by stimulating the amygdala or the auditory cortex behind the rhinal sulcus (ACBRS), and in particular, the GABA induced suppression could be completely antagonized by application of bicuculline. Taken together, these data suggested that GABA mediated the amygdaloid inhibitory effect. It seemed unlikely that glycine was involved in the effect, since strychnine, a glycine antagonist, could not affect the descending inhibition from ACBRS area.
Yang
L
L
Brain Function Research Laboratory, East China Normal University, Shanghai 200062.
Dong
X W
XW
Feng
M Z
MZ
Wu
Q Y
QY
Zhou
S C
SC
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D005072:Evoked Potentials, Auditory; D018756:GABA Antagonists / Q000494:pharmacology; D005829:Geniculate Bodies / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D011817:Rabbits; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology / Q000502:physiology*
D018756:GABA Antagonists; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline