Expression of mRNA encoding vasopressin V1a, vasopressin V2, and ANP-B receptors in the rat cochlea

Abstract

The expression of mRNAs encoding vasopressin V1a, V2, and ANP-B receptors in the rat cochlea was examined by PCR and in situ hybridization. After reverse-transcription of rat cochlear RNA, cDNA was amplified by PCR using pairs of primers specific to these receptors. After subcloning of the PCR products, clones with sequences identical to those cloned previously from the rat liver (V1a receptor), kidney (V2 receptor) and brain (ANP-B receptor) were obtained. The localization of expression of those receptors in the developing and adult rat cochlea was examined by in situ hybridization using 35S-labeled cRNA probes. The V1a and V2 receptors were expressed throughout the whole of the neonatal rat cochlea, while no expression was detected in the adult cochlea. The ANP-B receptor was expressed throughout the whole of the neonatal cochlea. In the adult cochlea, expression was observed in the spiral ganglion and the spiral ligament. These results suggest that vasopressin may play a role in the development of the cochlea, and that natriuretic peptide may play a role in the function of the spiral ganglion and the spiral ligament.