The medial amygdala enhances synaptic transmission and synaptic plasticity
in the dentate gyrus of rats in vivo.
Ikegaya, Yuji, Kazuho Abe, Hiroshi Saito and Nobuyoshi Nishiyama.
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences,
The University of Tokyo, Tokyo 113, Japan.
APStracts 2:0248N, 1995.
SUMMARY AND CONCLUSIONS
1 . The present experiment was designed to test whether synaptic transmission
and synaptic plasticity in the dentate gyrus were modulated by the medial
amygdala (MeA). Field potentials in the dentate gyrus (DG) evoked by
stimulations of the medial perforant path (PP) were extracellularly recorded
in anesthetized rats. 2 . While single-pulse stimulation of the MeA augmented
PP stimulation-evoked population spike amplitude in the DG transiently, high-
frequency stimulation (100 Hz for 1 s) of the MeA induced long-lasting
enhancement of synaptic transmission that was not occluded by PP tetanus-
induced long-term potentiation (LTP). 3 . When high-frequency stimulation of
the MeA was applied concurrently with weak tetanus of the PP, which alone
induced only marginal LTP, the magnitude of LTP increased considerably. 4 .
These results demonstrate that neuron activities in the MeA induce short- and
long-lasting changes in the excitability of the PP-DG synapses and thereby
enhance their synaptic plasticity.
Received 11 May 1995; accepted in final form 25 July 1995.
APS Manuscript Number J317-5.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 August 1995.