title: Exercise sensitizes skeletal muscle to extracellular ATP for IL-6 expression in mice.
abstract: Active skeletal muscle synthesizes and releases interleukin-6 (IL-6), which plays important roles in the organism's adaptation to exercise. Autocrine/paracrine ATP signaling has been shown to modulate IL-6 expression. The aim of this study was to determine whether a period of physical activity modifies the ATP-induced IL-6 expression. BalbC mice were either subject to 5 weeks voluntary wheel running (VA) or kept sedentary (SED). Flexor digitorum brevis muscles were dissected, stimulated with different ATP concentrations (0-100 μM) and IL-6 mRNA levels were measured using qPCR. ATP evoked a concentration-dependent rise in IL-6 mRNA in both SED and VA mice. VA mice however, had significantly higher ATP sensitivity (pD2 pharmacological values: VA=5.58±0.02 vs. SED=4.95±0.04, p<0.05). Interestingly, in VA mice we observed a positive correlation between the level of physical activity and the IL-6 mRNA increase following fiber stimulation with 10 μM ATP. In addition, there were lower P2Y2- and higher P2Y14-receptor mRNA levels in skeletal muscles of VA compared to SED mice, showing plasticity of nucleotide receptors with exercise. These results suggest that exercise increases skeletal muscle ATP sensitivity, a response dependent on the level of physical activity performed. This could have an important role in the mechanisms controlling skeletal muscle adaptation to exercise and training.
authors.affiliation: Centro de Estudios Moleculares de la Célula, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: R
authors.initials: R
authors.lastname: Fernández-Verdejo
authors.affiliation: Centro de Estudios Moleculares de la Célula, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: M
authors.initials: M
authors.lastname: Casas
authors.affiliation: Departamento de Nutrición, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: J E
authors.initials: JE
authors.lastname: Galgani
authors.affiliation: Centro de Estudios Moleculares de la Célula, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: E
authors.initials: E
authors.lastname: Jaimovich
authors.affiliation: Centro de Estudios Moleculares de la Célula, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: S
authors.initials: S
authors.lastname: Buvinic
mesh_terms: D000222:Adaptation, Physiological; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D019898:Autocrine Communication / Q000502:physiology; D015992:Body Mass Index; D002950:Citrate (si)-Synthase / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D010805:Physical Conditioning, Animal; D012333:RNA, Messenger / Q000378:metabolism; D058470:Receptors, Purinergic P2Y / Q000378:metabolism; D012420:Running / Q000502:physiology*
chemical_list: D015850:Interleukin-6; D012333:RNA, Messenger; D058470:Receptors, Purinergic P2Y; D000255:Adenosine Triphosphate; D002950:Citrate (si)-Synthase