Characterization of specific receptors for atrial natriuretic factor on cultured bovine brain capillary endothelial...

A specific receptor for rat atrial natriuretic factor (rANF) was identified on primary cultures of bovine brain capillary endothelial cells (BBCEC's). Cultured BBCEC's have been developed in our laboratory as an in vitro model of the blood-brain barrier. The binding of [125I]-rANF was rapid, reversible, saturable and unaffected by the presence of hormonal peptides such as insulin, vasopressin and angiotensin II. Scatchard analysis of competitive binding studies indicated the presence of a single class of binding sites for rANF with a dissociation constant of 400 pM and maximal binding capacity of 52 fmol/mg total cell protein. Binding of [125I]-rANF was inhibited to varying degrees by atriopeptins I-III with atriopeptin III being the most potent and atriopeptin I being the least potent. BBCEC's also rapidly internalized [125I]-rANF (100% after 60 min at 37 degrees C) by a temperature-dependent process.