TY - JOUR
T1 - Vasodilatory effect of nicorandil on coronary arterial microvessels
T2 - Its dependency on vessel size and the involvement of the ATP-sensitive potassium channels
AU - Akai, Kenjiro
AU - Wang, Yan
AU - Sato, Kouichi
AU - Sekiguchi, Nobuyo
AU - Sugimura, Akihiko
AU - Kumagai, Toshinobu
AU - Komaru, Tatsuya
AU - Kanatsuka, Hiroshi
AU - Shirato, Kunio
PY - 1995/10
Y1 - 1995/10
N2 - We aimed to clarify the size dependency of nicorandil-induced dilation in coronary microcirculation and the involvement of adenosine triphosphate (ATP)-sensitive potassium channels. Coronary arterial microvessels were observed through a microscope equipped with a floating objective in anesthetized open-chest dogs (n = 29). Heart rate and mean aortic pressure were maintained at control level. In 16 dogs, nicorandil was infused into the coronary in a cumulative fashion (0.1, 1.0, 10, and 100 μg/kg/min, for 5 min for each dose). In 13 dogs, glibenclamide (10 μM) was topically applied onto the observed area, and nicorandil was similarly infused. Nicorandil dilated vessels < 100 μm indiameter at all applied doses in a dose-dependent manner. Glibenclamide abolished the dilation of these vessels at the lower two doses. Vessels >100 μm in diameter dilated only at the two higher doses and the dilation was not affected by glibenclamide. These data suggest that the vessels < 100 μm are more sensitive to this agent than other size vessels, and that ATP-sensitive potassium channels are involved in the nicorandil-induced dilation of vessels smaller than 100 μm, whereas the dilation of other size vessels occurs independently of this channel.
AB - We aimed to clarify the size dependency of nicorandil-induced dilation in coronary microcirculation and the involvement of adenosine triphosphate (ATP)-sensitive potassium channels. Coronary arterial microvessels were observed through a microscope equipped with a floating objective in anesthetized open-chest dogs (n = 29). Heart rate and mean aortic pressure were maintained at control level. In 16 dogs, nicorandil was infused into the coronary in a cumulative fashion (0.1, 1.0, 10, and 100 μg/kg/min, for 5 min for each dose). In 13 dogs, glibenclamide (10 μM) was topically applied onto the observed area, and nicorandil was similarly infused. Nicorandil dilated vessels < 100 μm indiameter at all applied doses in a dose-dependent manner. Glibenclamide abolished the dilation of these vessels at the lower two doses. Vessels >100 μm in diameter dilated only at the two higher doses and the dilation was not affected by glibenclamide. These data suggest that the vessels < 100 μm are more sensitive to this agent than other size vessels, and that ATP-sensitive potassium channels are involved in the nicorandil-induced dilation of vessels smaller than 100 μm, whereas the dilation of other size vessels occurs independently of this channel.
KW - ATP-sensitive K channel
KW - Coronary circulation
KW - Glibenclamide
KW - Microcirculation
KW - Nitrate
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U2 - 10.1097/00005344-199510000-00006
DO - 10.1097/00005344-199510000-00006
M3 - Article
C2 - 8569213
AN - SCOPUS:0029079906
VL - 26
SP - 541
EP - 547
JO - Journal of Cardiovascular Pharmacology
JF - Journal of Cardiovascular Pharmacology
SN - 0160-2446
IS - 4
ER -