The Journal of Neuroscience, December 15, 1999, 19(24):10656-10663
Long-Term Depression of Excitatory Synaptic Transmission in the
Rat Amygdala
Su-Jane
Wang and
Po-Wu
Gean
Department of Pharmacology, College of Medicine, National
Cheng-Kung University, Tainan, Taiwan 701
In view of the fact that both kindling and fear-potentiated startle
are expressed by long-term enhancement of synaptic transmission in the
amygdala, synaptic plasticity in this area of the brain is of
particular importance. Here, we show for the first time that
low-frequency stimulation of the lateral nucleus at 1 Hz for 15 min elicited a long-term depression (LTD) in the basolateral amygdala
(BLA) neurons. LTD is expressed specifically at the lateral-BLA synapses but not at ventral endopyriform nucleus-BLA synapses. The
induction of LTD requires activation of both NMDA and
metabotropic glutamate receptors. Loading cells with a
Ca2+ chelator BAPTA or extracellular superfusion
with protein phosphatase inhibitors prevents LTD, suggesting that LTD
may result from dephosphorylation of AMPA receptors. The same
stimulating protocol could not elicit LTD in neurons from kindled
animals, whereas neurons from sham-operated or age-matched control rats
were able to exhibit LTD. Together, this study characterizes the
properties of LTD in the naïve amygdala slices for the first
time and demonstrates that epileptogenesis in vivo
induces disruption of LTD in the in vitro preparation.
Key words:
long-term depression; neuronal plasticity; amygdala; kindling; epilepsy; fear conditioning
Copyright © 1999 Society for Neuroscience 0270-6474/99/192410656-08$05.00/0