AP5 and CNQX decrease post-tetanic potentiation at the crayfish neuromuscular junction

Abstract

This study looks at the roles of the glutamate receptors alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid (AMPA) and N-methyl-D-aspartic acid (NMDA) in post-tetanic potentiation (PTP) at the neuromuscular junction of Orconectes. In previous studies, researchers used ketamine to antagonize the NMDA receptors in crayfish; however, ketamine also affects other glutamate receptors including AMPA. Research on the individual roles of the AMPA and NMDA receptors in crayfish may lead to a better understanding of their influence in humans. We introduced the AMPA receptor antagonist CNQX and the NMDA receptor antagonist AP5 into crayfish saline solution to block the receptors and observe their individual roles in synaptic transmission and plasticity. Using electrophysiological techniques, we measured changes in excitatory postsynaptic potentials (EPSPs) and PTP resulting from CNQX and AP5. We found that while CNQX and AP5 did not affect EPSP amplitude, both drugs significantly decreased PTP.