title: Alterations in circulating cyclic guanosine monophosphate (c-GMP) during short and long ischemia in preconditioning.
abstract: The aim of this study was to investigate if levels of circulating cyclic guanosine monophosphate (c-GMP) alter in preconditioning. Twenty-eight rabbits were divided into four groups. In vivo hearts were preconditioned, either with 5 min (group A, n = 8) or with 1 min (group B, n = 8) ischemia, followed by 10 min reperfusion, while groups C (n = 7) and D (n = 5) had no interventions. Protection was determined by subjecting groups A, B and C (but not D) to 30 min regional ischemia which was followed (including group D) by 2 h reperfusion. Seven blood samples were collected for the assessment of circulating c-GMP at different points of time. All results were expressed in pmol/ml using radio-immunoassay and the infarcted to risk area in percent using fluorescent particles and tetrazolium chloride (TTC). Circulating c-GMP increased during long ischemia only in group A (baseline value 47 +/- 4, long ischemic values 60.5 +/- 4 and 60.4 +/- 4, p < 0.05). Circulating c-GMP in group A was significantly higher in the middle of the long ischemia in comparison to the groups B, C and D (60.5 +/- 4 vs 43.9 +/- 4, 45.8 +/- 5 and 43.6 +/- 4, p < 0.05). Infarcted to risk ratio was lower in group A than in groups B and C (12.2 +/- 4 vs 29.6 +/- 6 and 34.2 +/- 6 respectively, p < 0.05). Circulating c-GMP is increased in classically preconditioned in comparison to ineffectively preconditioned hearts or to control groups. This elevation may be related to the protective effect of this phenomenon.
authors.affiliation: Department of Cardiology, Onassis Cardiac Surgery Center, Athens, Greece.
authors.forename: E K
authors.initials: EK
authors.lastname: Iliodromitis
authors.forename: C C
authors.initials: CC
authors.lastname: Papadopoulos
authors.forename: M
authors.initials: M
authors.lastname: Markianos
authors.forename: I A
authors.initials: IA
authors.lastname: Paraskevaidis
authors.forename: Z S
authors.initials: ZS
authors.lastname: Kyriakides
authors.forename: D T
authors.initials: DT
authors.lastname: Kremastinos
mesh_terms: D000818:Animals; D006152:Cyclic GMP / Q000378:metabolism*; D006439:Hemodynamics; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D008297:Male; D009203:Myocardial Infarction / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D011817:Rabbits; D011863:Radioimmunoassay
chemical_list: D006152:Cyclic GMP