Splanchnic and cerebral vasodilatory effects of calcitonin gene-related peptide I in humans.

The ability of synthetic human calcitonin gene-related peptide (CGRP I) to act as an arterial vasodilator was tested in healthy men by measuring arterial blood flow parameters in carotid, superior mesenteric, celiac, and femoral vessels. Calculated volume flow was significantly increased (140 +/- 21% of basal) in the SMA with a 2-ng/kg/min infusion of CGRP. Carotid artery volume flow increased dose dependently (96 +/- 6%, 122 +/- 15%, 135 +/- 15% of basal, respectively, with 2, 4, or 8 ng/kg/min). With steady-state infusion, carotid and superior mesenteric arterial flow parameters remained significantly elevated for 30 minutes after cessation of peptide administration. Blood pressure was unchanged. Pulse increased dose dependently. Arterial diameters were unchanged, implying activity at the arteriolar level.