The involvement of neuropeptide YY1 receptors in the blood pressure baroreflex:: studies with BIBP 3226 and BIBO 3304

To ascertain the role of the neuropeptide Y Y-1 receptors in the vascular manifestations of the sympathetic baroreflex, 10-s bilateral carotid occlusions were performed in anesthetized cats; systemic blood pressure was monitored continually. This maneuver rose systolic blood pressure in 23 +/- 2 mmHg. Following 100 mu g/kg BIBP 3226 or BIBO 3304 i.v., the increase in blood pressure elicited by the occlusions was only 14 +/- 1 and 15 mmHg, respectively. Both BIBP 3226 and BIBO 3304 displaced significantly 5.5 fold rightward the presser dose-response curve elicited by exogenous neuropeptide Y, without altering the norepinephrine curve. Prazosin (10 mu g/kg) reduced the presser response elicited by the carotid occlusion to 12 +/- 4 mmHg. The simultaneous administration of BIBP 3226 plus prazosin rose the systemic blood pressure following the occlusion only 9 +/- 2 mmHg, supporting the involvement of neuropeptide Y in vascular sympathetic reflexes. (C) 1999 Elsevier Science B.V. All rights reserved.