Flow regulates vasodilator responses to acetylcholine in the isolated canine mesenteric arterial bed

Raising the flow rate of the perfusate from 10 to 20 ml/min significantly suppressed vasodilator responses to acetylcholine, but not to sodium nitroprusside, in the isolated canine mesenteric arterial bed. Both acetylcholine and sodium nitroprusside augmented guanosine 3',5'-cyclic monophosphate (cyclic GMP) levels in the effluent from the vascular bed preparation, though cyclic GMP responses to these agents were not affected by raising the flow rate. These data suggest that the suppression, via raising the flow rate, of vasodilator responses to acetylcholine is not due to impaired function of the nitric oxide (NO)-cyclic GMP pathway in the mesenteric arterial bed.