Expression Of Atrial Natriuretic Peptide (ANP) And Its Receptor In Different Age Groups' Rats Cochlea

Objective:To detect the expression of atrial natriuretic peptide (ANP) and its receptor(NPR-A) in the developing rats'cochlea and in the marginal cell culture from stria vascularis.Methods: 1,Tissues were removed from the different group rats'cochlear.To assess the possible physiological role of the atrial natriuretic peptide(ANP) and its receptor in rat inner ear using the reverse transcription-polymerase-chain reaction method;2,The cochlea strial vascularises were isolated under a dissecting microscopy as explants,then culture in vitro to get the monolayer epithelial cells ,RT-PCR was used to detect the expression of ANP and NPR-A. Results: 1,We showed that ANP and NPR-A were both expressed in rat cochlea at early postnatal period. During the maturation , ANP expression was down-regulated while NPR-A expression was relatively stable. 2,ANP and NPR-A were detected in the cochlea strial vascularises'cultured cell.Conclusion: 1,We systematically examined the expression of ANP and NPR-A from the time of after birth into adulthood. Based on our previous report and the present study,there is a high likehood that the ANP plays an important role in the growth and development process of rat cochlea.but ANP may act as an paracrine manner or a circulating hormone in the mature rat.2,ANP and NPR-A can detect in cultured strial vascularise cells.It is said that the exvivo cells of young rats have the function to secrete ANP.