CHARACTERIZATION OF AXONALLY TRANSPORTED [I-125] PYY BINDING-SITES IN RAT VAGUS NERVE

Quantitative receptor autoradiography was used to characterize [I-125]PYY binding to slide-mounted sections of rat cervical vagus nerve which had been ligated 24 h prior to extraction. Saturation and competitive binding characteristics were determined for the accumulation of binding sites detected in the segment of the nerve proximal to the ligature. High and low affinity binding components were resolved (K(d) = 93 pM and 2.1 nM). The rank order of potency for competing ligands was PYY > NPY >> PYY13-36 >>> [Pro34]NPY suggesting that vagal PYY/NPY binding sites are PYY-preferring and of the Y2 type.