Two skeletal muscle membrane responses were examined to evaluate the role of membrane alterations in dystrophic muscle function. These responses - norepinephrine evoked changes in membrane conductance and potential - have been suggested to be associated with nonshivering metabolic pathways independent of contractile events. Norepinephrine (at concentrations ranging from 50-300 μg/kg) and/or saline was injected intravenously into anesthetized control hamsters and Bar Harbor 14.6 cardiomyopathic hamsters (2-3 months old). Glass microelectrodes were used to measure the intracellular potentials and membrane resistances of gracilis anticus cells. In the normal hamsters, norepinephrine administration was followed by a small, but significant membrane depolarization (X̄=6.7±1.4 mV) and a decrease in membrane resistance (X̄=1.0±0.1 mΩ). In contrast, saline had little or no effect on these parameters. The voltage and resistance changes observed in dystrophic muscle cells were in the same direction as those occurring in the normal muscle, but were significantly smaller in magnitude. The finding that these norepinephrine-induced changes were diminished in dystrophic cells supports the view that membrane properties thought not to be associated with muscle contraction are altered in dystrophic hamster muscle.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the Society for Experimental Biology and Medicine|
|State||Published - 1980|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)