title: Continuous detection of superoxide in situ during ischemia and reperfusion in the rabbit heart.
abstract: In order to clarify the time course of superoxide generation in situ during ischemia and reperfusion in the rabbit heart, we used a method of enhanced chemiluminescence (CL) with 2-methyl-6-[p-methoxyphenyl]-3, 7-dihydroimidazo [1, 2-alpha]pyrazin-3-one (MCLA) as a specific probe for detecting superoxide radicals. The surface of the rabbit heart was exposed to a photomultiplier tube in a light-proof box. We introduced a reversible snare occluder into the box to continuously observe the light emission. An ischemia-reperfusion group (I/R, n = 7) was subjected to 30 mins of coronary occlusion, followed by 90 mins of reperfusion. We performed the same procedure (except for coronary occlusion) in the sham-operated group (n = 4). Another group of rabbits (n = 4) subjected to I/R received superoxide dismutase (SOD: 20 mg/kg, i.v.) during reperfusion to observe the CL response. In the I/R-group, the increase in CL began at 13 +/- 2 (mean +/- SEM) mins and peaked at 52 +/- 12 mins of reperfusion. CL in the I/R-group gradually increased from 818 +/- 350 counts/10 secs in the preischemic period to 1077 +/- 401 counts/10 secs during reperfusion (p < 0.01). In contrast, there was no increase in CL in the sham-operated group. The administration of SOD briefly attenuated CL by 24.1 +/- 6.8% for a period of 24.3 +/- 6.8 mins. The superoxide generation in situ in the ischemic rabbit heart appears to increase gradually and persists for a period following reperfusion.
authors.affiliation: First Department of Internal Medicine, Fukushima Medical College, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ushiroda
authors.forename: Y
authors.initials: Y
authors.lastname: Maruyama
authors.forename: M
authors.initials: M
authors.lastname: Nakano
mesh_terms: D000818:Animals; D003326:Coronary Circulation; D005609:Free Radicals; D006439:Hemodynamics; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology; D008163:Luminescent Measurements; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000378:metabolism* / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism*; D011719:Pyrazines / Q000008:administration & dosage / Q000494:pharmacology; D011817:Rabbits; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism*
chemical_list: D005609:Free Radicals; D007093:Imidazoles; D011719:Pyrazines; D013481:Superoxides; C063412:2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyrazin-3-one; D013482:Superoxide Dismutase