BINDING OF ATRIAL AND BRAIN NATRIURETIC PEPTIDES TO CULTURED MOUSE ASTROCYTES FROM DIFFERENT BRAIN-REGIONS AND EFFECT ON CYCLIC-GMP PRODUCTION

We prepared primary cultures of mouse astrocytes from the cerebral cor tex, hypothalamus, and cerebellum to examine the possibility of region al disparity in binding of human atrial and porcine brain natriuretic peptides (hANP, pBNP) and their effect on cyclic guanosine monophospha te (cGMP) production. I-125-hANP and I-125-pBNP bound in a specific an d saturable manner to all three regions. For both peptides, Scatchard analysis suggested a single population of binding sites on astrocytes from all three regions. No significant differences were observed in th e maximal binding capacities (B(max)) or binding dissociation constant s (K(D)) between the two peptides in the astrocyte preparations from d ifferent regions. ANP and BNP also evoked cGMP stimulation in a simila r, dose-dependent fashion in astrocytes from all three regions, with m aximal responses to both peptides reached at a concentration above 1 m uM. While BNP elicited a greater maximal cGMP accumulation than ANP, n o difference could be demonstrated in the cGMP responses to either pep tide between brain regions. Thus we have been unable to demonstrate re gional heterogeneity in the responsiveness of astrocytes to ANP and BN P. (C) 1993 Wiley-Liss, Inc.