REGULATION OF NPY NPY Y-1 RECEPTOR/G PROTEIN SYSTEM IN RAT-BRAIN CORTEX/

Neuropeptide Y (NPY) content, NPY receptors, and alpha-subunits of the G proteins G(o) and G(i) were determined in cerebral cortex of male n ormotensive Wistar-Kyoto and spontaneously hypertensive rats at 3-28 w k of age and of adult female rats. NPY lacked major effects on adenyla te cyclase or inositol phosphate formation. NPY content was similar in all normotensive groups but lower in spontaneously hypertensive rats at all ages. I-125-NPY labeled a homogeneous population of Y-1-like re ceptors. The Y-1 NPY receptor number gradually increased with age with similar values in both strains but was significantly smaller in femal e than in male rats. The Y-1 NPY receptor affinity was similar in all male groups but greater in female rats. The abundance of immunodetecta ble G(o) alpha and G(i) alpha and of pertussis toxin substrates was le ss at 3 wk than in older rats but similar in both sexes and strains. W e conclude that rat cerebral cortex contains Y-1-like receptors; sex, age, and blood pressure differentially regulate NPY content, Y-1 NPY r eceptors, and G(o) alpha and G(i) alpha.