Long-term enhancement of EPSP and NMDA receptor-mediated synaptic transmission in the amygdala

Abstract An in vitro slice preparation of rat amygdala was used to study the long-term modifications of synaptic efficacy following high-frequency stimulation of the ventral endopyriform nucleus. Delivery of brief tetani to the afferent fibers led to a long-term potentiation (LTP) of the amplitude and the initial slope of excitatory postsynaptic potential (EPSP). Pretreatment the slices with DL-2-amino-5-phosphonovaleate (DL-APV, 50 μM) blocked the induction of LTP, indicating that N-methyl-D-aspartate (NMDA) receptor activation is required for induction. NMDA receptor-mediated component of synaptic response (EPSP NMDA ) was isolated by application of a solution containing 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX. 10 μM) and bicuculline (20 μM). Tetanic stimulation led to a lasting potentiation of the EPSP NMDA . These results suggest that brief repetitive stimulation of afferent pathway produces forms of LTP that share many properties of LTP seen in the CA1 region of the hippocampus.

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