Identification of an NPY-Y1 receptor subtype in bovine chromaffin cells

Bovine chromaffin cells have been used in a variety of studies designed to reveal different aspects of neuropeptide Y (NPY) action. Pharmacological da ta have defined five NPY receptor subtypes, only one of which (Y3) has not been cloned. Some studies with bovine chromaffin cells have concluded that the effects of NPY on this cell type are mediated by the Y3 subtype. Previo us work from our laboratory demonstrates that a Y1 subtype mediates the eff ect of NPY in this tissue. In the current studies we provide further eviden ce for the existence of the Y1 subtype in bovine chromaffin cells. BIBP3226 , the selective Y1 antagonist, potently displaces [I-125]NPY from its bindi ng site IC50 = 1.91x10(-9) M. Moreover, [I-125]BIBP3226 binds to bovine chr omaffin cell membranes with high affinity (IC50 = 5.9 x 10(-8) M). Examinat ion of BIBP3226 antagonism of NPY inhibition of forskolin stimulated cyclic AMP accumulation reveals that it is a competitive antagonist with a K-B si milar to the IC50 for [I-125]BIBP3226 binding. Northern blot analysis using a porcine cDNA clone for the Y1 subtype demonstrates a 3.5-kb mRNA species in chromaffin cells. These data identify the bovine chromaffin cell NPY re ceptor as a Y1 subtype. (C) 2000 Elsevier Science B.V. All rights reserved.