LOCALIZATION AND CHARACTERISTICS OF ATRIAL-NATRIURETIC-PEPTIDE RECEPTORS IN PRENATAL AND POSTNATAL RAT-BRAIN

We studied the expression of atrial natriuretic peptide (ANP) receptor subtypes during development in the rat forebrain, using quantitative autoradiography. Highest ANP binding was observed in the cortical neur oepithelium at embryonic day 17. Lower ANP binding was found in cingul ate and frontal cortices at postnatal day 10, but none was detectable at 8 weeks of age. In the neuroepithelium of the embryonic rat, bindin g was displaced with a potency of rat ANP-(1-28) (rANP) > porcine type -C natriuretic peptide (pCNP-22) = rat ANP fragment C-ANP-(4-23) (rC-A NP-(4-23)) = rat brain natriuretic peptide (rBNP-32), different from t hat of any of the well-characterized (ANP(A), ANP(B), and ANP(C)) natr iuretic peptide receptors. The present results support the hypothesis of a role for ANP during brain maturation and indicate that the ANP re ceptors highly expressed in the embryonic neuroepithelium may belong t o a new ANP receptor subtype not yet characterized.