Intravenous adenosine reduces myocardial no-reflow by decreasing endothelin-1 via activation of the ATP-sensitive K+ channel.
It has been verified that adenosine can attenuate myocardial no-reflow. However, the effects of adenosine on adenosine triphosphate-sensitive K+ (KATP) channel and endothelin-1 (ET-1) are unknown.


METHODS
Forty mini-swines were randomized into 5 study groups: 8 in the control group, 8 in the adenosine pretreatment group, 8 in the glibenclamide (K(ATP) channel blocker)-treated group, 8 in the adenosine and glibenclamide-pretreated group and 8 in the sham-operated group. An acute myocardial infarction and reperfusion model was created with three-hour occlusion of the left anterior descending coronary artery followed by a one-hour reperfusion.


RESULTS
Compared with the control group, adenosine significantly decreased the area of no-reflow (myocardial contrast echocardiography: from 78.5 +/- 4.5% to 20.7 +/- 4.1%, pathological means: from 82.3 +/- 1.9% to 21.5 +/- 4.3% of ligation area, respectively; all P < 0.01), reduced necrosis size from 98.5 +/- 1.3% to 75 +/- 4.7% of ligation area, P < 0.05). It also decreased plasma ET-1 and myocardial tissue ET-1. However, glibenclamide abrogated the protective effect of adenosine.


CONCLUSIONS
The beneficial effect of adenosine on myocardial no-reflow could be due to its effect on ET-1 via the activation of K(ATP) channel.
Zhao
Jing-Lin
JL
Fu-Wai Heart Hospital, Beijing, People's Republic of China.
Yang
Yue-Jin
YJ
Pei
Wei-Dong
WD
Sun
Yu-Hua
YH
Chen
Ji-Lin
JL
Go
Run-Lin
RL
D000241:Adenosine / Q000008:administration & dosage*; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects*; D004195:Disease Models, Animal; D004452:Echocardiography; D019332:Endothelin-1 / Q000097:blood* / Q000187:drug effects; D007275:Injections, Intravenous; D054086:KATP Channels / Q000187:drug effects / Q000378:metabolism*; D009203:Myocardial Infarction / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D011863:Radioimmunoassay; D011897:Random Allocation; D013552:Swine; D013556:Swine, Miniature; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000008:administration & dosage*
D019332:Endothelin-1; D054086:KATP Channels; D014665:Vasodilator Agents; D000241:Adenosine