title: Cardioprotection due to preconditioning correlates with increased ecto-5'-nucleotidase activity.
abstract: We investigated whether loss of myocardial protection after ischemic preconditioning (IP) is related to the extent of deactivation of activated ecto-5'-nucleotidase. The coronary arteries of mongrel dogs were occluded four times for 5 min separated by 5 min of reperfusion (IP). Five (IP1), 30 (IP2), 60 (IP3), and 120 min (IP4) after the fourth 5-min coronary occlusion or after a corresponding nonischemic period (control groups), the coronary arteries were occluded for 90 min followed by 6 h of reperfusion. The infarct size-limited effect of IP gradually disappeared in the IP2 (21.6 +/- 3.9%) and IP3 (33.8 +/- 3.6%) groups compared with the IP1 group (8.3 +/- 1.6%) and returned to the control level in the IP4 group (39.9 +/- 5.2%). The increased ecto-5' -nucleotidase activity due to the IP procedure decreased according to the order of IP1 to IP4 groups. Infarct size was inversely correlated with ecto-5'-nucleotidase activity (P < 0.001). An inhibitor of ecto-5'-nucleotidase blunted the infarct size-limiting effect of IP. The infarct size-limiting effect of IP decreased as the activation of ecto-5'-nucleotidase was blunted. These results suggest that ecto-5'-nucleotidase activity plays a key role in the cardioprotection of IP.
authors.affiliation: First Department of Medicine, Osaka University School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Minamino
authors.forename: M
authors.initials: M
authors.lastname: Kitakaze
authors.forename: T
authors.initials: T
authors.lastname: Morioka
authors.forename: K
authors.initials: K
authors.lastname: Node
authors.forename: K
authors.initials: K
authors.lastname: Komamura
authors.forename: H
authors.initials: H
authors.lastname: Takeda
authors.forename: M
authors.initials: M
authors.lastname: Inoue
authors.forename: M
authors.initials: M
authors.lastname: Hori
authors.forename: T
authors.initials: T
authors.lastname: Kamada
mesh_terms: D015720:5'-Nucleotidase / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D003600:Cytosol / Q000378:metabolism; D004285:Dogs; D005260:Female; D006439:Hemodynamics; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology; D017202:Myocardial Ischemia / Q000503:physiopathology*; D012008:Recurrence; D013997:Time Factors
chemical_list: C523965:alpha,beta-methyleneadenosine 5'-diphosphate; D000244:Adenosine Diphosphate; D015720:5'-Nucleotidase