» Articles » PMID: 8842504

No Evidence for Mediation of Ischemic Preconditioning by Alpha 1-adrenergic Signal Transduction Pathway or Protein Kinase C in the Isolated Rat Heart

Overview
Date 1996 May 1
PMID 8842504
Citations 1
Authors
Affiliations
Soon will be listed here.
Abstract

The purpose of this study was to elucidate the role of activation of the alpha 1-adrenergic signal transduction pathway and of protein kinase C (PKC) in the mechanism of protection of functional recovery by ischemic preconditioning in the isolated perfused rat heart. After a stabilization period, nonpreconditioned and preconditioned isolated perfused rat hearts were subjected to sustained ischemia for 25 and 30 minutes of reperfusion. Preconditioning consisted of three episodes of 5 minutes of ischemia, interspersed with 5 minutes of reperfusion. The endpoint was postischemic functional recovery. The effectiveness of preconditioning in the presence of the alpha 1-adrenergic blocker prazosin, the selective PKC blockers chelerythrine and bisindolylmaleimide (BIM), and the ability of repetitive alpha 1-adrenergic activation to mimic preconditioning were compared with the appropriate nonpreconditioned and preconditioned control groups. Alpha 1-adrenergic blockade with prazosin (3 x 10(-7) M) during the preconditioning phase did not abolish the protective effect of preconditioning on functional recovery, and repeated intermittent alpha 1-adrenergic activation with phenylephrine in different concentrations (1 x 10(-8) to 3 x 10(-5) M) did not mimic the protective effect of preconditioning. PKC blockade with the selective PKC inhibitors, chelerythrine (10 microM) and BIM (4 microM), did not abolish the protective effect of preconditioning on functional recovery is isolated perfused rat hearts when given either during the preconditioning phase or shortly before the onset of sustained ischemia. The characteristic metabolic changes of preconditioning during sustained ischemia, namely, energy sparing as manifested in reduced accumulation of lactate, were also not abolished by preconditioning in the presence of selective PKC blockers. We conclude that no evidence could be found for alpha 1-adrenergic or PKC activation in the mechanism of ischemic preconditioning in the isolated rat heart.

Citing Articles

Protection of the ischaemic heart: investigations into the phenomenon of ischaemic preconditioning.

Lochner A, Marais E, Genade S, Huisamen B, Du Toit E, Moolman J Cardiovasc J Afr. 2009; 20(1):43-51.

PMID: 19287816 PMC: 4200578.

References
1.
Cave A, Collis C, Downey J, Hearse D . Improved functional recovery by ischaemic preconditioning is not mediated by adenosine in the globally ischaemic isolated rat heart. Cardiovasc Res. 1993; 27(4):663-8. DOI: 10.1093/cvr/27.4.663. View

2.
Thornton J, DALY J, Cohen M, Yang X, Downey J . Catecholamines can induce adenosine receptor-mediated protection of the myocardium but do not participate in ischemic preconditioning in the rabbit. Circ Res. 1993; 73(4):649-55. DOI: 10.1161/01.res.73.4.649. View

3.
Ytrehus K, Liu Y, Downey J . Preconditioning protects ischemic rabbit heart by protein kinase C activation. Am J Physiol. 1994; 266(3 Pt 2):H1145-52. DOI: 10.1152/ajpheart.1994.266.3.H1145. View

4.
Murry C, Richard V, Reimer K, Jennings R . Ischemic preconditioning slows energy metabolism and delays ultrastructural damage during a sustained ischemic episode. Circ Res. 1990; 66(4):913-31. DOI: 10.1161/01.res.66.4.913. View

5.
Weselcouch E, Baird A, Sleph P, Dzwonczyk S, Murray H, Grover G . Endogenous catecholamines are not necessary for ischaemic preconditioning in the isolated perfused rat heart. Cardiovasc Res. 1995; 29(1):126-32. View