Effects of nimodipine on noise-induced hearing loss.
The effects of nimodipine, a calcium channel blocker, on noise-induced hearing loss were examined in gerbils. Animals were implanted subcutaneously with a timed-release pellet containing either nimodipine (approximately 10 mg/kg/day) or placebo and exposed to either 102 or 107 dBA noise. Serum levels were tested in two subjects and were in the range known to protect humans from cerebral artery vasospasm and ischemia-related neurologic deficits. Nimodipine and control groups had similar amounts of noise-induced (a) permanent threshold shift; (b) reductions in distortion product otoacoustic emissions; (c) reductions in tuning and suppression of the compound action potential; and (d) loss of outer hair cells. The results suggest that nimodipine, at a dose which results in clinically relevant serum levels, does not provide protection from the effects of moderately intense noise exposures.
Boettcher
F A
FA
Department of Otolaryngology and Communicative Sciences, Medical University of South Carolina, Charleston 29425-2242, USA. boettcfa@musc.edu
Caldwell
R K
RK
Gratton
M A
MA
White
D R
DR
Miles
L R
LR
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001309:Auditory Threshold / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D003051:Cochlea / Q000187:drug effects* / Q000473:pathology; D003692:Delayed-Action Preparations; D004594:Electrophysiology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects; D005849:Gerbillinae; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects / Q000473:pathology; D006317:Hearing Loss, Noise-Induced / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D009553:Nimodipine / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D017084:Otoacoustic Emissions, Spontaneous / Q000187:drug effects
D002121:Calcium Channel Blockers; D003692:Delayed-Action Preparations; D009553:Nimodipine