Electrophysiological comparison of the effects of MCI-154 on smooth muscles between mesenteric artery and vein of dogs.
1. Effects of MCI-154, a cardiotonic vasodilator, on smooth muscles were compared in isolated mesenteric artery and vein of dog. 2. MCI-154 depolarized the membrane, and inhibited Ca(2+)- and K(+)-contractions more in the vein than in the artery. 3. Nerve-mediated and noradrenaline-induced contractions, and the excitatory junction potential (e.j.p.) were inhibited by MCI-154 in the vein and potentiated in the artery. 4. Compound action potentials of perivascular nerves and action potentials generated on the e.j.p. were not altered by MCI-154. 5. MCI-154 predominantly dilates venous muscles, and as a result would reduce cardiac outflow and lower systemic blood pressure.
Hashitani
H
H
Department of Pharmacology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Chen
G
G
Ono
H
H
Seki
N
N
Li
Y
Y
Nagao
T
T
Suzuki
H
H
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002316:Cardiotonic Agents / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology; D008642:Mesenteric Veins / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism; D011724:Pyridazines / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
D002316:Cardiotonic Agents; D011724:Pyridazines; D014665:Vasodilator Agents; C052228:MCI 154; D002118:Calcium; D009638:Norepinephrine