The Contradictory Effects of N-acetylaspartylglutamate and its Products of Hydrolysis on NMDARs in the Crayfish Neuromuscular Junction.

Abstract

NAAG is the most abundant peptide neurotransmitter in the mammalian nervous system, but relatively little is known about its function in glutamatergic synapses. Recent research has suggested NAAG to be a neuromodulator of glutamate release, but how it modulates glutamate release is unclear. The objective of this research was to see if NAAG has an effect on NMDARs and to determine if the hydrolyzed products of NAAG aid in modulation of NMDAR function. We did this using a crayfish synapse as a model system, specifically the extensor muscles in the tail, and applied NAAG to the synapse as well as LY341495 (a potent mGluR group II antagonist) to isolate the effect of NAAG on the other probable receptor, NMDAR. We then added ZJ43 along with NAAG onto the synapse to view the effects of pure NAAG on the synapse. Our results suggest that NAAG and its products of hydrolysis have an inhibitory effect on EPSP amplitude, and pure NAAG enhances EPSP amplitude.