(connexion internet requise)

Other Formats:  (connexion internet requise)  (connexion internet requise)

Links:  (connexion internet requise)

Order this document

Hear Res 1989 Jun 15;40(1-2):45-53

The quinoxalinediones DNOX, CNOX and two related congeners suppress hair cell-to-auditory nerve transmission.

Littman T, Bobbin RP, Fallon M, Puel JL

Louisiana State University Medical School, Kresge Hearing Research Laboratory, New Orleans, Louisiana 70112.

We tested 6,7-dinitroquinoxaline-2,3-dione (DNQX); 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX); 6,7-dichloro-3-hydroxy-2-quinoxalinecarboxylic acid (DHQC); and 3-hydroxy-2-quinoxalinecarboxylic acid (3HQC), new kainate and quisqualate receptor antagonists, upon cochlear potentials in guinea pig. Perilymph spaces of guinea pig cochleae were perfused with artificial perilymph solutions containing up to 1000 microM concentrations of DHQC and 3HQC, and 500 microM concentrations of DNQX and CNQX, at a rate of 2.5 microliters/min for 10 min. Cochlear potentials evoked by 10 kHz tone bursts of varying intensity were recorded from the basal turn scala vestibuli. Cochlear perfusion of the four drugs resulted in a dose-related suppression of the compound action potential of the auditory nerve (CAP; N1-P1), a prolongation of N1 latency at suprathreshold levels, an elevated CAP threshold, and a decreased N1 latency at CAP threshold. None of the drugs had significant effects on cochlear microphonics (CM) or the summating potential (SP). EC50 values (concentrations causing a 50% reduction in CAP amplitude at 68 dB SPL) were 8 microM for DNQX, 30 microM for DHQC, 35 microM for CNQX, and 1 mM for 3HQC. Results support the hypothesis that kainate and quisqualate receptors are involved in neurotransmission between the hair cell and afferent nerve.

PMID: 2570055, UI: 89358891

the above report in format
documents on this page through Loansome Doc