K. Sakai et al., DIFFERENTIAL-EFFECTS OF NICORANDIL ON THE VASODEPRESSOR RESPONSES TO VASOACTIVE POLYPEPTIDES ADMINISTERED INTRAVENOUSLY TO RATS, Journal of Pharmacy and Pharmacology, 50(2), 1998, pp. 211-214
The effects of nicorandil on vasodepressor responses to vasoactive int
estinal polypeptide (VIP), calcitonin gene-related peptide (CGRP) and
substance P have been examined in anaesthetized rats. Intravenous bolu
s injections of VIP (0.3 mu g kg(-1)), CGRP (0.1 mu g kg(-1)) and subs
tance P (0.1 mu g kg(-1)) induced reductions of blood pressure accompa
nied by slight increases (less than 5%) in heart rate. Nicorandil infu
sed intravenously at 10 or 30 mu g kg(-1) min(-1) significantly augmen
ted the vasodepressor responses to VIP and CGRP but did not modify the
responses to substance P and acetylcholine (0.1 mu g kg(-1)). Intrave
nous treatment with glibenclamide (20 mu g kg(-1)) significantly atten
uated not only the vasodepression caused by VIP and CGRP, but also the
enhancement of the effects of the agents by nicorandil. These results
indicate that nicorandil can enhance the action of VIP and CGRP, in r
ats, at least partly through ATP-sensitive K+-channel activation.