Auditory and Vestibular Systems, Lateral LineSerotonergic innervation of the organ of corti of the cat cochleaGil-Loyzaga, Pablo1,2; Bartolomé, M Visitación1; Vicente-Torres, M Angeles1Author Information 1Centro de Cultivos Celulares (CAI-UCM) and Departamento de Cirugía II (ORL), Faculty of Medicine, University Complutense, Apartado de Correos 60075, 28080 Madrid, Spain 2Corresponding Author: Pablo Gil-Loyzaga Received 6 August 1997; accepted 2 September 1997 NeuroReport: November 10th, 1997 - Volume 8 - Issue 16 - p 3519-3521 Buy Abstract THE presence and distribution of serotonin-containing fibers within the adult cat cochlea is reported here for the first time. The 5-HT-like immunoreactive fibers were mainly found in the middle coils of the cat cochlea, following a peripheral distribution similar to that of the olivocochlear lateral efferent system (OLES). Thus, 5-HT-like immunoreactive varicose fibers were found within the intraganglionic spiral bundle, the inner and the tunnel bundles, although, some variation with the distribution of other neuroactive substances of the OLES were observed. In particular, some isolated fibers from the tunnel bundle branched towards the first row of the outer hair cells. Cochlear serotonergic fibers might be involved in the auditory processing within the cochlea as efferent modulating fibers. © Lippincott-Raven Publishers.