Role of MaxiK channels in vasoactive intestinal peptide-induced relaxation of rat mesenteric artery.
We investigated the functional relevance of large conductance voltage-dependent and Ca(2+)-sensitive K(+)(MaxiK) channels in vasoactive intestinal peptide (VIP)-induced relaxation of rat mesenteric artery. VIP, which is known to increase cAMP levels, produced a concentration-dependent relaxation in endothelium-denuded arteries. Iberiotoxin, a MaxiK channel blocker, greatly diminished the VIP-induced relaxation. In a similar manner, a significant portion of the relaxant response to dibutyryl-cAMP (DBcAMP), a membrane-permeable analog of cAMP, was inhibited by iberiotoxin. These results suggest that activation of MaxiK channels significantly contributes to the relaxant response of rat mesenteric artery to VIP, possibly via cAMP-mediated pathways.
Tanaka
Y
Y
Department of Pharmacology, Toho University School of Pharmaceutical Sciences, 2-2-1 Miyama, Funabashi, Japan. yotanaka@phar.toho-u.ac.jp
Mochizuki
Y
Y
Hirano
H
H
Aida
M
M
Tanaka
H
H
Toro
L
L
Shigenobu
K
K
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology; D010455:Peptides / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D014118:Toxins, Biological / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology* / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology
D010455:Peptides; D015221:Potassium Channels; D014118:Toxins, Biological; D014660:Vasoactive Intestinal Peptide; D003994:Bucladesine; C064719:iberiotoxin