title: Substrains of inbred mice differ in their physical activity as a behavior.
abstract: Recent studies strengthen the belief that physical activity as a behavior has a genetic basis. Screening wheel-running behavior in inbred mouse strains highlighted differences among strains, showing that even very limited genetic differences deeply affect mouse behavior. We extended this observation to substrains of the same inbred mouse strain, that is, BALB/c mice. We found that only a minority of the population of one of these substrains, the BALB/c J, performs spontaneous physical activity. In addition, the runners of this substrain cover a significantly smaller distance than the average runners of two other substrains, namely, the BALB/c ByJ and the BALB/c AnNCrl. The latter shows a striking level of voluntary activity, with the average distance run/day reaching up to about 12 kilometers. These runners are not outstanders, but they represent the majority of the population, with important scientific and economic fallouts to be taken into account during experimental planning. Spontaneous activity persists in pathological conditions, such as cancer-associated cachexia. This important amount of physical activity results in a minor muscle adaptation to endurance exercise over a three-week period; indeed, only a nonsignificant increase in NADH transferase+ fibers occurs in this time frame.
authors.affiliation: UR4 Aging, Stress, Inflammation, University Pierre et Marie Curie Paris 6, 7 Quai Saint Bernard, 75005 Paris, France. dario.coletti@snv.jussieu.fr
authors.forename: Dario
authors.initials: D
authors.lastname: Coletti
authors.forename: Emanuele
authors.initials: E
authors.lastname: Berardi
authors.forename: Paola
authors.initials: P
authors.lastname: Aulino
authors.forename: Eleonora
authors.initials: E
authors.lastname: Rossi
authors.forename: Viviana
authors.initials: V
authors.lastname: Moresi
authors.forename: Zhenlin
authors.initials: Z
authors.lastname: Li
authors.forename: Sergio
authors.initials: S
authors.lastname: Adamo
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001835:Body Weight; D005260:Female; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008928:Mitochondria / Q000502:physiology; D009043:Motor Activity; D018485:Muscle Fibers, Skeletal / Q000201:enzymology / Q000502:physiology; D053580:Muscle Strength; D009247:NADH, NADPH Oxidoreductases / Q000032:analysis; D010084:Oxidation-Reduction; D010807:Physical Endurance / Q000502:physiology*; D013997:Time Factors
chemical_list: D009247:NADH, NADPH Oxidoreductases