title: Nifedipine diminishes exercise-induced muscle damage in mouse.
abstract: The purpose of this study was to evaluate the effects of a calcium channel blocker (nifedipine) on the severity of muscle damage induced by intensive exercise. Male Charles River mice were assigned to four groups (8 mice/group): normal control (C), nifedipine (N), nifedipine and exercise (N + E) and exercise (E). The animals of the C group were not submitted to any exercise nor to drug administration. The animals of the N group received 1 mg.kg-1 per day of nifedipine (Adalat 10 mg, Bayer AG), per os, during 3 days. The mice of the N + E group were submitted to a treadmill run (0 degree slope) at 1000 m.h-1 (80% of their maximal speed) for 1 hour. In this group, the administration of the drug was under the same conditions as for the N group. The administration started 24 h before the run. The E group was submitted to the same exercise protocol as the animals of N + E group. The soleus muscle was excised for light and electron microscopic evaluation using routine histological techniques. In the C and N groups no morphological alterations were detected. In the E group the number of alterations of striated pattern was twice that in the N + E group. The number of fibres with central nuclei was 35% in the E group but only 8% in the N + E group. The total number of damaged fibres was significantly higher in the E group. The results suggest that nifedipine may give protection to exercise-induced skeletal muscle damage in mouse, probably because the blocking of channels impaired Ca2+ influx; and the results of this study therefore confirm earlier contentions about the possible role of calcium ions in producing muscle damage after work.
authors.affiliation: Department of Sport Biology, Faculty of Sport Sciences, University of Porto.
authors.forename: J A
authors.initials: JA
authors.lastname: Duarte
authors.forename: J M
authors.initials: JM
authors.lastname: Soares
authors.forename: H J
authors.initials: HJ
authors.lastname: Appell
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers; D008297:Male; D051379:Mice; D009000:Monocytes; D009132:Muscles / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D009336:Necrosis / Q000473:pathology; D009543:Nifedipine / Q000494:pharmacology*; D005082:Physical Exertion; D013312:Stress, Physiological / Q000473:pathology
chemical_list: D002121:Calcium Channel Blockers; D009543:Nifedipine