Noise stimulation decreases the concentration of norepinephrine in the rat cochlea.
The present study was designed to analyze, by using high performance liquid chromatography (HPLC), the effect of acoustic stimulation on the cochlear concentration of norepinephrine (NE). Independently of the rat strain (Long-Evans or Wistar strains), NE concentration decreased about 18% when animals were exposed to white noise (90 dB SPL for 1 h). The same decrease was observed in animals perfused by aortic pathway to remove the blood, indicating that this decrease corresponds exclusively to a neurophysiological process. In fact, these findings could indicate that noise stimulation is involved in the NE release from sympathetic fibers innervating the cochlea. This likely release of NE supports that sympathetic fibers play a functional role in cochleae exposed to noisy situations.
Vicente-Torres
M A
MA
Centro de Cultivos Celulares (CAI) and Departamento de Cirugia II (ORL), Facultad de Medicina, Universidad Complutense de Madrid, Spain.
Gil-Loyzaga
P
P
D000161:Acoustic Stimulation; D000704:Analysis of Variance; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003051:Cochlea / Q000378:metabolism*; D008297:Male; D009622:Noise; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D020318:Rats, Long-Evans; D017208:Rats, Wistar; D012880:Skin Pigmentation
D009638:Norepinephrine