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Evidence For The Involvement Of Camkii And Ampk In Ca2+-Dependent Signaling Pathways Regulating Fa Uptake And Oxidation In Contracting Rodent Muscle, Marcella Raney, Lorraine Turcotte
Evidence For The Involvement Of Camkii And Ampk In Ca2+-Dependent Signaling Pathways Regulating Fa Uptake And Oxidation In Contracting Rodent Muscle, Marcella Raney, Lorraine Turcotte
Marcella Raney
Calcium-calmodulin/dependent protein kinase II (CaMKII), AMP-activated protein kinase (AMPK), and extracellular signal-regulated kinase (ERK1/2) have each been implicated in the regulation of substrate metabolism during exercise. The purpose of this study was to determine whether CaMKII is involved in the regulation of FA uptake and oxidation and, if it is involved, whether it does so independently of AMPK and ERK1/2. Rat hindquarters were perfused at rest with (n = 16) or without (n = 10) 3 mM caffeine, or during electrical stimulation (n = 14). For each condition, rats were subdivided and treated with 10 μM of either KN92 or …
Evidence For The Regulation Of Contraction-Induced Fatty Acid Oxidation Via Extracellular Signal-Regulated Kinase 1/2 Activation Independent Of Changes In Fatty Acid Uptake, Marcella Raney, Lorraine Turcotte
Evidence For The Regulation Of Contraction-Induced Fatty Acid Oxidation Via Extracellular Signal-Regulated Kinase 1/2 Activation Independent Of Changes In Fatty Acid Uptake, Marcella Raney, Lorraine Turcotte
Marcella Raney
Abstract Data show that extracellular signal-regulated kinase 1/2 (ERK1/2) may be involved in the regulation of fatty acid (FA) uptake during muscle contraction via stimulation of CD36 translocation to the plasma membrane. The perfused hind limb model was used to determine (1) the importance of ERK1/2 signaling on contraction-induced FA uptake and (2) the effect of ERK1/2-mediated FA uptake on contraction-induced FA oxidation. We perfused rat hind limbs with 8 mmol/L glucose, 550 μmol/L palmitate, and no insulin at rest in the absence of inhibitor and during moderate-intensity electrical stimulation and dose-dependent pharmacologic inhibition of ERK1/2 using increasing concentrations of …
Effects Of Muscle Contraction On The Signaling Mechanisms Regulating Fatty Acid Metabolism, Marcella Raney
Effects Of Muscle Contraction On The Signaling Mechanisms Regulating Fatty Acid Metabolism, Marcella Raney
Marcella Raney
This dissertation is composed of four experiments designed to more clearly define the components of the signaling cascades which regulate FA uptake and oxidation in skeletal muscle during acute muscle contraction. In the first experiment, AICAR treatment in the perfused hindquarter activated the signaling molecule AMPK and increased FA uptake and oxidation. However, during low intensity muscle contraction FA uptake and oxidation were both significantly increased despite no significant increase in AMPK activity compared to rest. In addition, combination of AICAR treatment and low intensity muscle contraction resulted in a more than additive increase in FA oxidation in skeletal muscle. …
Regulation Of Contraction-Induced Fa Uptake And Oxidation By Ampk And Erk1/2 Is Intensity Dependent In Rodent Muscle, Marcella Raney, Lorraine Turcotte
Regulation Of Contraction-Induced Fa Uptake And Oxidation By Ampk And Erk1/2 Is Intensity Dependent In Rodent Muscle, Marcella Raney, Lorraine Turcotte
Marcella Raney
Muscle contraction activates AMP-activated protein kinase (AMPK) and extracellular signal-regulated kinase (ERK1/2), two signaling molecules involved in the regulation of muscle metabolism. The purpose of this study was to determine whether activation of AMPK and/or ERK1/2 contributes to the regulation of muscle fatty acid (FA) uptake and oxidation in contracting muscle. Rat hindquarters were perfused during rest (R) or electrical stimulation (E) of increasing intensity by manipulating train duration (E1 = 25 ms, E2 = 50 ms, E3 = 100 ms, E4 = 200 ms). For matched FA delivery, FA uptake was significantly greater than R during E1, E2, and …
Ampk Activation Is Not Critical In The Regulation Of Muscle Fa Uptake And Oxidation During Low-Intensity Muscle Contraction, Marcella Raney, Alice Yee, Mark Todd, Lorraine Turcotte
Ampk Activation Is Not Critical In The Regulation Of Muscle Fa Uptake And Oxidation During Low-Intensity Muscle Contraction, Marcella Raney, Alice Yee, Mark Todd, Lorraine Turcotte
Marcella Raney
To determine the role of AMP-activated protein kinase (AMPK) activation on the regulation of fatty acid (FA) uptake and oxidation, we perfused rat hindquarters with 6 mM glucose, 10 μU/ml insulin, 550 μM palmitate, and [14C]palmitate during rest (R) or electrical stimulation (ES), inducing low-intensity (0.1 Hz) muscle contraction either with or without 2 mM 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR). AICAR treatment significantly increased glucose and FA uptake during R (P < 0.05) but had no effect on either variable during ES (P > 0.05). AICAR treatment significantly increased total FA oxidation (P < 0.05) during both R (0.38 ± 0.11 vs. 0.89 ± 0.1 nmol·min−1·g−1) and ES (0.73 ± 0.11 vs. 2.01 ± 0.1 nmol·min−1·g−1), which was paralleled in both conditions by a significant increase and significant decrease in AMPK and acetyl-CoA carboxylase (ACC) activity, respectively (P < 0.05). Low-intensity muscle contraction increased glucose uptake, FA uptake, and total FA oxidation (P < 0.05) despite no change in AMPK (950.5 ± 35.9 vs. 1,067.7 ± 58.8 nmol·min−1·g−1) or ACC (51.2 ± 6.7 vs. 55.7 ± 2.0 nmol·min−1·g−1) activity from R to ES (P > 0.05). When contraction and AICAR treatment were combined, the AICAR-induced increase in AMPK activity (34%) did not account for the synergistic increase in …