European Journal of Anatomy

Official Journal of The Spanish Society of Anatomy
Cover Volume 3 - Number 3
Eur J Anat, 3 (3): 153-162 (1999)

A detailed map of c-fos activation in the rat cochlear complex following different kinds of sound stimuli

Riera-Sala C., Martinez-Beneyto P., Marco-Algarra J., Martinez-Soriano F., Olucha F.E.

Dpto. Ciencias Morfologicas, Facultad de Medicina y Odontologia, Univ. de Valencia, Avda. Blasco Ibanez 17, E-46010-Valencia, Spain

ABSTRACT The pattern of c-fos expression was mapped in the rat cochlear nuclei following different types of sound stimuli. To assess the location of the c-fos activated nuclei, parallel series were reacted for acetyl cholinesterase. The histochemical reaction was quantified by means of an image analysis system. Stimuli for c-fos expression consisted in 1KHz, 20 KHz and a combination of 4 tones. An additional control group consisted of rats isolated in a sound-proof room 24 hours before testing. The cochlear complex was divided into six rostro-caudal levels. The anterior ventral cochlear nucleus extended from level I to level III. In isolated rats, this nucleus did not show c-fos activation. In contrast, all kinds of sound stimuli led to c-fos activation, which occurred in the dorsolateral part of the nucleus at all levels. The posterior ventral cochlear nucleus extended from level I to V. No labeling was found in isolated rats. Different kinds of sound stimulation led to different patterns of c-fos activation. The granular cell layer occupied the superficial border of the complex from level I to level V. An increase in c-fos activation was seen following all types of sound stimulation. In four tones stimulated rats more c-fos labeling was seen than in one tone stimulated rats but no differences were seen in the distribution of activated nuclei. The dorsal cochlear nucleus extended from level III to level VI. It showed no labeling in isolated conditions. Sound stimuli led to an increase in c-fos labeling. Different kinds of sound stimuli led to different patterns of both the distribution and intensity in c-fos activation. These results allow the inference that all nuclei of the cochlear complex can be activated following sound stimulation through the activation of immediate early genes such as c-fos. C-fos activation may play important roles in long term plastic changes at the cochlear complex level.

Keywords: acetylcholinesterase, messenger RNA, animal cell, animal experiment, article, auditory nervous system, auditory stimulation, cochlea, controlled study, gene activation, gene expression, histochemistry, immediate early gene, immunocytochemistry, male, nonhuman, oncogene c fos, rat

European Journal of anatomy
ISSN 2340-311X (Online)