Localization of the Atrial Natriuretic Peptide Binding Sites in the Inner Ear Tissue—Possibly an Additional Regulating System

Abstract

Specific high affinity atrial natriuretic peptide (ANP) binding sites were identified and localized by autoradiography (125J-ANP 1-28) in the inner ear of guinea pigs. ANP is a cardiac hormone known to mediate increased capillary permeability, vasodilation, and natriuresis. Since specific receptors for ANP exist in both eye and brain, possibly playing a role in regulation of fluid and pressure (14, 15), we hypothetized that ANP might be involved also in inner ear fluid dynamics via interaction with other volume/electrolyte balance regulating hormones including vasopressin, renin, and aldosteron. The distribution of ANP receptor in the inner ear tissue appears unequal, which may play a significant role in view of some functional disturbances such as Meniere's disease.