Mitochondrial KATP channels in skeletal muscle: are protein kinases C and G, and nitric oxide synthase involved in the fatigue process?

ochondrial KATP channels in skeletal muscle: are protein kinases C and G, and nitric oxide synthase involved in the fatigue process? Original Research (941) Total Article Views Authors: Sánchez-Duarte E, Trujillo X, Huerta M, Ortiz-Mesina M, Cortés-Rojo C, Manzo-ávalos S, Saavedra-Molina A, Montoya-Pérez R Published Date October 2012 Volume 2012:4 Pages 21 - 28 DOI: http://dx.doi.org/10.2147/OAAP.S34818 Received: 08 June 2012 Accepted: 09 August 2012 Published: 25 October 2012 Elizabeth Sánchez-Duarte,1 Xóchitl Trujillo,1 Miguel Huerta,1 Mónica Ortiz-Mesina,1 Christian Cortés-Rojo,2 Salvador Manzo-ávalos,2 Alfredo Saavedra-Molina,2 Rocío Montoya-Pérez3 1Unidad de Investigación Enrico Stefani Bonfanti, Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, México; 2Instituto de Investigaciones Químico-Biológicas, 3Coordinación General de Estudios de Posgrado Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México Background: Fatigue in skeletal muscle is defined as a reduction in the physical power needed to execute a function or as an inability to maintain mitochondrial ATP production. The mitochondrial potassium channel (mitoKATP) participates in combating fatigue in skeletal muscle. In this work, we evaluated the role of the mitoKATP channel activator (diazoxide) and inhibitors of the signaling routes (protein kinase C, staurosporine; protein kinase G, KT5823; and nitric oxide synthase, metil NG-Nitro-L-arginine ester, L-NAME), on muscle fatigue tension. In addition, we evaluated the main signaling routes used by the nitric oxide synthase protein and protein kinase C and G, in the presence of their specific activators. Methods: We used the anterior latissimus dorsi skeletal muscle of 2–3-week-old chicks. This muscle consists of slow muscle fibers. Tension was achieved by applying repetitive electrical stimulation that induced fatigue in an in vitro model. Results: Diazoxide significantly reduced muscle fatigue (P = 0.0002 in peak tension, P = 0.000002 in maximum tension) by increasing post-fatigue tension, in spite of the fact that 5-hydroxydecanoate, a selective inhibitor of mitoKATP, did not suppress post-fatigue tension. Conclusion: Our results suggest a lack of direct interaction in inhibition of the signaling routes during fatigue-induced mitoKATP activation. This effect is possibly due to the type of skeletal muscle fibers (slow), the stimulation protocols (twitch), and the animal (avian) model used in the study.