title: Hindlimb muscle fibre size and glycogen stores in bank voles with increased aerobic exercise metabolism.
abstract: To test hypotheses concerning physiological factors limiting the rate of aerobic exercise metabolism, we used a unique experimental evolution model: lines of bank voles selected for high swim-induced aerobic metabolism (A) and unselected, control lines (C). We investigated putative adaptations that result in the increased performance of the hindlimb muscle (gastrocnemius joined with plantaris). The body mass-adjusted muscle mass was higher in A-lines (0.093 g) than in C-lines (0.083 g; P=0.01). However, selection did not affect mean muscle fibre cross-sectional area (P=0.34) or glycogen content assessed with a histochemical periodic acid-Schiff reaction (PAS; P=0.82). The results suggest that the increased aerobic performance is achieved by an increase of total muscle mass, without major qualitative changes in the muscle fibre architecture. However, such a conclusion should be treated with caution, because other modifications, such as increased density of capillaries or mitochondria, could occur.
authors.affiliation: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Krakow 30-387, Poland ewa.jaromin@uj.edu.pl.
authors.forename: Ewa
authors.initials: E
authors.lastname: Jaromin
authors.affiliation: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Krakow 30-387, Poland.
authors.forename: Julia
authors.initials: J
authors.lastname: Wyszkowska
authors.affiliation: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Krakow 30-387, Poland.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Labecka
authors.affiliation: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Krakow 30-387, Poland.
authors.forename: Edyta Teresa
authors.initials: ET
authors.lastname: Sadowska
authors.affiliation: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Krakow 30-387, Poland.
authors.forename: Paweł
authors.initials: P
authors.lastname: Koteja
mesh_terms: D000818:Animals; D003411:Arvicolinae / Q000235:genetics / Q000378:metabolism*; D004734:Energy Metabolism / Q000235:genetics*; D006003:Glycogen / Q000378:metabolism*; D006614:Hindlimb; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism*; D010805:Physical Conditioning, Animal; D013550:Swimming
chemical_list: D006003:Glycogen
keywords: Aerobic capacity; Artificial selection; Fibre types; Gastrocnemius; Locomotor performance; Myodes glareolus