α1-Adrenergic receptor antagonist blocks acute cocaine action on the compound action potential of the auditory nerve in the chinchilla

Abstract

Acute systemic cocaine injection is known to significantly decrease the compound action potential (CAP) amplitude of the auditory nerve. In an attempt to elucidate the mechanism underlying this phenomenon, the present study investigated the influence of prazosin, an adrenergic α 1-receptor antagonist, on the effect of cocaine on the CAP. Amplitude-intensity functions at 1 and 8 kHz were obtained before and after treatment with cocaine (experimental group) or saline (control group) in prazosin pretreated subjects. The characteristic reduction in CAP amplitude after an acute cocaine injection was blocked by 0.05 mg/kg prazosin. When subjects were re-injected with cocaine or saline one h after prazosin, the reduction in CAP amplitude following cocaine injection had recovered.