RESUMO
BACKGROUND AND OBJECTIVES: Damage in the auditory sensory epithelia is irreversible and the resulting hearing loss is permanent in mammals. Nevertheless, mammals like birds can recover their auditory function anatomically and physiologically after the sensorineural hearing loss. One of the functions of a receptor tyrosine kinase is to controll the cellular metabolisms like motility, growth, differentiation, regeneration, and ion transport via various pathways. There are no reports on the distribution of receptor tyrosine kinases in the guinea pig cochlea. The purpose of this study is to evaluate the expression of the fibroblast growth factor receptor (FGFR) and transforming growth factor receptor (TGFR-beta, type II ) in the cochlear sensory epithelia of guinea pigs. MATERIALS AND METHODS: We investigated the immunoreactivity and functional roles of the receptor tyrosine kinases-FGFR and TGFR-beta (type II) - by using surface preparation technique in the cochlea of the Preyer's positive, pigmented guinea pig. RESULTS: The results showed that receptor tyrosine kinases were expressed in the cytoplasm of Deiter's and Hensen's cells to FGFR and TGFR-beta (type II), and the stereocillia of inner and outer hair cells to FGFR by surface preparation technique. CONCLUSION: The findings suggest that receptor tyrosine kinases are involved in the cellular growth, differentiation and regeneration in the cochlear supporting cells, and ion transport in the hair cells of the mammals. We found that receptor tyrone kinases are not related to outer hair cells participating in the PLCgamma1-IP3 second messenger system.