caa a22 4500 477072631 CHVBK 20180405111430.0 cr unu---uuuuu 170330e19961001xx s 000 0 eng 10.1007/BF00823590 doi (NATIONALLICENCE)springer-10.1007/BF00823590 No evidence for mediation of ischemic preconditioning by alpha1-adrenergic signal transduction pathway or protein kinase C in the isolated rat heart [Elektronische Daten] [Johannes Moolman, Sonia Genade, Erna Tromp, Amanda Lochner] Summary: The purpose of this study was to elucidate the role of activation of the alpha1-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 alpha1-adrenergic blocker prazosin, the selective PKC blockers chelerythrine and bisindolylmaleimide (BIM), and the ability of repetitive alpha1-adrenergic activation to mimic preconditioning were compared with the appropriate nonpreconditioned and preconditioned control groups. Alpha1-adrenergic blockade with prazosin (3×10-7 M) during the preconditioning phase did not abolish the protective effect of preconditioning on functional recovery, and repeated intermittent alpha1-adrenergic activation with phenylephrine in different concentrations (1×10-8 to 3× 10-5 M) did not mimic the protective effect of preconditioning. PKC blockade with the selective PKC inhibitors, chelerythrine (10 μM) and BIM (4 μM), 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 alpha1-adrenergic or PKC activation in the mechanism of ischemic preconditioning in the isolated rat heart. Kluwer Academic Publishers, 1996 preconditioning nationallicence alpha1-adrenergic signal transduction nationallicence protein kinase C nationallicence prazosin nationallicence Moolman Johannes Department of Internal Medicine, Faculty of Medicine, Tygerberg, South Africa aut Genade Sonia Department of Internal Medicine, Faculty of Medicine, Tygerberg, South Africa aut Tromp Erna Department of Internal Medicine, Faculty of Medicine, Tygerberg, South Africa aut Lochner Amanda Department of Internal Medicine, Faculty of Medicine, Tygerberg, South Africa aut Cardiovascular Drugs and Therapy Kluwer Academic Publishers 10/2(1996-10-01), 125-136 0920-3206 10:2<125 1996 10 10557 https://doi.org/10.1007/BF00823590 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00823590 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Moolman Johannes Department of Internal Medicine, Faculty of Medicine, Tygerberg, South Africa aut NATIONALLICENCE 700 1- Genade Sonia Department of Internal Medicine, Faculty of Medicine, Tygerberg, South Africa aut NATIONALLICENCE 700 1- Tromp Erna Department of Internal Medicine, Faculty of Medicine, Tygerberg, South Africa aut NATIONALLICENCE 700 1- Lochner Amanda Department of Internal Medicine, Faculty of Medicine, Tygerberg, South Africa aut NATIONALLICENCE 773 0- Cardiovascular Drugs and Therapy Kluwer Academic Publishers 10/2(1996-10-01), 125-136 0920-3206 10:2<125 1996 10 10557 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer