Distribution and location of immunoreactive atrial natriuretic peptides in cochlear stria vascularis of guinea pig.

The distribution and location of atrial natriuretic peptides (ANP) in the cochlear stria vascularis of normal guinea pigs were studied to find out regional regulating factors of cochlear blood flow (CBF) and productive foundation of cochlear endolymph by ABC immunocytochemistry and immunoelectronmicroscopy. The ANP-IR products were seen in the stria vascularis of the 1-4 turns of the lateral wall of the cochlea, more markedly along its margin; and were negative in the spiral ligaments. Immunoelectron-microscopically, a plenty of sphericals of 250-350nm in diameter were noted in the cytoplasm of marginal and intermediate cells, but few in the basal cells. The results suggest that the cochlear stria vascularis had the function of secreting ANP in the guinea pig.