Effects of endothelin-1 on the myogenic contraction of canine cerebral artery in response to quick stretch.
The present study was performed to investigate the effects of endothelin-1 (ET-1) on the myogenic contraction in response to mechanical stimulation in cerebral artery. Quick stretch at a rate of 10 cm/sec with the amount of 10 - 40% of the initial muscle length (=100%) produced a myogenic contraction in canine cerebral artery. ET-1 at 30 pM, which itself produces a small contraction corresponding to about 15% of the maximal response, potentiated stretch-induced contraction. By contrast, ET-1 at concentrations over 100 pM suppressed the stretch-induced tone. The potentiated component of stretch-induced tone in the presence of 30 pM ET-1 was largely attenuated by Ca2+ channel blockers, nimodipine (1 microM) or diltiazem (1 microM). These findings suggest that lower concentrations (pM range) of ET- 1 potentiates myogenic tension development of cerebral artery in response to mechanical stretch possibly via an increased Ca2+ influx through voltage-gated Ca2+ channel.
Tanaka
Y
Y
Department of Pharmacology, Toho University School of Pharmaceutical Sciences, Funabashi-City, Chiba, Japan. yotanaka@phar.toho-u.ac.jp
Shigenobu
K
K
Nakayama
K
K
D000818:Animals; D001488:Basilar Artery / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D002536:Cerebral Arteries / Q000187:drug effects* / Q000378:metabolism; D004285:Dogs; D019332:Endothelin-1 / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009470:Muscle Spindles / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009553:Nimodipine / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D019332:Endothelin-1; D014665:Vasodilator Agents; D009553:Nimodipine; D002118:Calcium