RECEPTORS FOR C-TYPE NATRIURETIC PEPTIDE IN CULTURED RAT GLIAL-CELLS

To characterize sites of action of C-type natriuretic peptide (CNP) in the glial cells, the effect of CNP on cGMP accumulation and the bindi ng of [I-125]CNP in rat astrocyte RCR-1 cells were studied. CNP stimul ated cGMP accumulation in the cells from 10(-9)) M in a dose-dependent manner, but ANP (atrial natriuretic peptide) had a negligible effect on cGMP accumulation in the cells. [I-125]CNP was bound to the cells a nd its K(d) value was 2 orders of magnitude lower than that of the ED5 0 value for stimulation of cGMP accumulation in the cells. Not only CN P but also ANP displaced [I-125]CNP binding to the cells. These result s suggest that RCR-1 cells have a B-receptor which contains a guanylat e cyclase domain and is preferentially activated by CNP, and that they also have a C-receptor which does not contain a guanylate cyclase dom ain that reacts with both ANP and CNP.