PYY-PREFERRING RECEPTOR IN THE DORSAL VAGAL COMPLEX AND ITS INVOLVEMENT IN PYY STIMULATION OF GASTRIC-ACID SECRETION IN RATS

1 Microinjection of peptide YY (PYY, 7-46 pmol) into the dorsal vagal complex (DVC) stimulated gastric acid secretion in urethane-anaestheti zed rats. Using a variety of neuropeptide Y (NPY) and PYY derivatives, we characterized the pharmacological profile of the receptor mediatin g the acid secretory response to PYY. 2 [Pro(34)]rat(r)/porcine(p)PYY and [Pro(34)]human(h)PYY (23-117 pmol), microinjected unilaterally int o the DVC resulted in a similar maximal increase in net acid secretion reaching 68+/-11 and 89+/-31 mu mol 90 min(-1) respectively. 3 Rat/hN PY and pNPY (47 pmol) microinjected into the DVC induced a similar net gastric acid secretion (27+/-8 and 23+/-8 mu mol 90 min(-1) respectiv ely) and a higher dose (116 pmol) tended to reduce the response. 4 Pan creatic polypeptide (PP, 4-46pmol), [Leu(31),Pro(34)]r/hNPY (47 and 11 7 pmol) and the Y2 selective agonists, hPYY(3-36), PNPY5-36 and pNPY(1 3-36) (25-168 pmol) microinjected into the DVC failed to influence bas al gastric acid secretion. 5 The rank order of potency of PYY greater than or equal to[Pro(34)]r/pPYY=[Pro(34)]hPYY>r/hNPY=pNPY to stimulate gastric acid secretion upon injection into the DVC and the ineffectiv eness of PP, [Leu(31),Pro(34)]NPY and C-terminal NPY/PYY fragments sug gest that a PYY-preferring receptor subtype may be involved in mediati ng the stimulating effect.