Elsevier

Hearing Research

Volume 52, Issue 1, March 1991, Pages 195-200
Hearing Research

Pharmacology of excitatory amino acid neurotransmission in nucleus laminaris of the chick

https://doi.org/10.1016/0378-5955(91)90199-JGet rights and content

Abstract

The receptors mediating excitatory neurotransmission from the cochlear nucleus (nuc. magnocellularis, NM) to third-order auditory neurons in nucleus laminaris (NL) of the chicken were studied using in vitro brain slices, bath application of drugs, and electrophysiological recording of postsynaptic field potentials. Postsynaptic responses in NL were blocked completely, in a concentration-dependent and reversible fashion, by bath application of the broad-spectrum excitatory amino acid (EAA) antagonist kynurenic acid, the ‘non-NMDA’ EAA receptor antagonists 6,7-dinitroquinoxaline-2,3-dione (DNQX) and 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo (F)quinoxaline (NBQX), and the EAA agonists domoic acid, kainic acid, α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), and quisqualic acid. The selective NMDA receptor antagonists 3-((−)-2-carboxypiperazin-4-yl)propyl-1-phosphonate (CPP) and dibenzocycloheptenimine (MK-801) had no effect. The results demonstrate that excitatory input from the cochlear nucleus to NL is mediated by non-NMDA (G2) EAA receptors which exhibit some of the pharmacologie features typical of the AMPA receptors defined by binding studies.

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