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Titolo:
EFFECTS OF (-)-BACLOFEN, CLONAZEPAM, AND DIAZEPAM ON TONE EXPOSURE-INDUCED HYPEREXCITABILITY OF THE INFERIOR COLLICULUS IN THE RAT - POSSIBLE THERAPEUTIC IMPLICATIONS FOR PHARMACOLOGICAL MANAGEMENT OF TINNITUSAND HYPERACUSIS
Autore:
SZCZEPANIAK WS; MOLLER AR;
Indirizzi:
PRESBYTERIAN UNIV HOSP,DEPT NEUROL SURG,SUITE B-400,200 LOTHROP ST PITTSBURGH PA 15213 UNIV PITTSBURGH,SCH MED,DEPT NEUROL SURG PITTSBURGH PA 15213
Titolo Testata:
Hearing research
fascicolo: 1-2, volume: 97, anno: 1996,
pagine: 46 - 53
SICI:
0378-5955(1996)97:1-2<46:EO(CAD>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
UNILATERAL COCHLEAR ABLATION; AGE-RELATED DECREASE; EVOKED-POTENTIALS; AUDITORY-CORTEX; TEMPORAL INTEGRATION; ADULT MAMMALS; INTENSE SOUND; GUINEA-PIGS; NUCLEUS; NEURONS;
Keywords:
PLASTICITY; AUDITORY EVOKED POTENTIAL; TINNITUS; BACLOFEN; CLONAZEPAM; DIAZEPAM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
43
Recensione:
Indirizzi per estratti:
Citazione:
W.S. Szczepaniak e A.R. Moller, "EFFECTS OF (-)-BACLOFEN, CLONAZEPAM, AND DIAZEPAM ON TONE EXPOSURE-INDUCED HYPEREXCITABILITY OF THE INFERIOR COLLICULUS IN THE RAT - POSSIBLE THERAPEUTIC IMPLICATIONS FOR PHARMACOLOGICAL MANAGEMENT OF TINNITUSAND HYPERACUSIS", Hearing research, 97(1-2), 1996, pp. 46-53

Abstract

Recent investigations in the authors' laboratory have shown that acute tone exposure (4 kHz continuous tone, 104 dB sound pressure level (SPL), 30-min duration) induces increases in the amplitude of click-evoked potentials in the inferior colliculus (IC). These increases have been attributed to a decrease in GABA(A)-mediated inhibition on IC neurons. In the present study, we examined the effects of three compounds (diazepam, clonazepam, and (-)-baclofen) that are known to enhance GABAergic inhibition on these tone exposure-induced increases and on changes in temporal integration in the IC. (-)-Baclofen was the only one ofthe three compounds tested that reversed in a dose-dependent manner the effects of tone exposure on both the amplitude of the click-evoked potentials recorded from the IC and on measures of the changes in temporal integration based on these potentials. Diazepam and clonazepam exhibited remarkably different effects on the click-evoked potentials recorded from the surface of the IC. Diazepam caused a dose-dependent decrease in one of the components of the IC potentials that reflects postsynaptic activity in the IC, whereas clonazepam caused a dose-dependent decrease in a peak that reflects input to the IC from the superior olivary complex (SOC). At dosages up to 40 mg/kg, neither diazepam norclonazepam reversed the changes in temporal integration in the IC that were induced by the tone exposure; diazepam caused a small, but statistically significant, enhancement of the effects of tone exposure on this function. The results of this study show that (-)-baclofen is a potent modulator of both the excitability of neurons in the ascending auditory pathway and the processing of auditory information by IC neurons. The finding of the present study that two benzodiazepines (clonazepam and diazepam) have remarkably different effects on evoked potentials, which reflects both input to the IC and postsynaptic events in theIC neurons, suggests heterogenicity of the GABA(A) receptor from one structure to another in the ascending auditory pathway. We suggest that (-)-baclofen may be clinically useful in treating disorders of the auditory system that are caused by plasticity in the ascending auditorypathway.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/01/20 alle ore 06:46:23