Pharmacologic evidence for synaptic transmission mediated by non-N-methyl-D-aspartate receptors in the avian cochlear nucleus.
The hypothesis that synaptic transmission between the auditory nerve and the cochlear nucleus is mediated by an excitatory amino acid acting through N-methyl-D-aspartate (NMDA) receptors was examined in an in vitro preparation of the chicken brainstem. The ability of various bath-applied excitatory amino acid receptor antagonists to inhibit synaptically-evoked responses was assessed by recording field potentials from nucleus magnocellularis (NM) following electrical stimulation of the cochlear nerve. Antagonists that selectively block responses mediated by NMDA receptors, such as D-alpha-aminoadipate and 2-amino-5-phosphonovalerate, were without effect on evoked transmission in NM. In contrast, antagonists that additionally act on non-NMDA receptors, such as cis-2,3-piperidine dicarboxylate and gamma-D-glutamylglycine, reversibly suppressed transmission. The results indicate that (1) transmission in the chicken auditory system is mediated by non-NMDA receptors, and (2) a substance(s) chemically akin to aspartate and glutamate may be the transmitter used by the auditory nerve in NM.
D000818:Animals; D001933:Brain Stem / Q000187:drug effects / Q000502:physiology*; D002645:Chickens / Q000502:physiology*; D003056:Cochlear Nerve / Q000187:drug effects / Q000502:physiology*; D005071:Evoked Potentials / Q000187:drug effects; D018377:Neurotransmitter Agents; D017981:Receptors, Neurotransmitter / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects
D018377:Neurotransmitter Agents; D017981:Receptors, Neurotransmitter