Cargando…
The Control of the Membrane Potential of Muscle Fibers by the Sodium Pump
Frog sartorius muscles were made Na-rich by immersion in K-free sulfate Ringer's solution in the cold. The muscles were then loaded with Na(24) and the extracellular space cleared of radioactivity. When such Na-rich muscles were transferred to lithium sulfate Ringer's solution at 20°C, Na...
Autores principales: | , |
---|---|
Formato: | Texto |
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
1965
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2213764/ https://www.ncbi.nlm.nih.gov/pubmed/14324987 |
Sumario: | Frog sartorius muscles were made Na-rich by immersion in K-free sulfate Ringer's solution in the cold. The muscles were then loaded with Na(24) and the extracellular space cleared of radioactivity. When such Na-rich muscles were transferred to lithium sulfate Ringer's solution at 20°C, Na efflux was observed to increase with time, to reach a maximum about 15 minutes after the transfer of the muscles to Li(2)SO(4), and then to decline. The decline in efflux from these muscles was proportional to ([Na](i))(8) over a considerable range of [Na](i). The membrane potential of Na-rich muscles was about -48 mv in K-free sulfate Ringer's at 4°C but changed to -76 mv in the same solution at 20°C and to -98 mv in Li(2)SO(4) Ringer's at 20°C. By contrast, muscles with a normal [Na](i) showed a fall in membrane potential when transferred from K-free sulfate Ringer's to Li(2)SO(4) Ringer's solution. The general conclusions from this study are (a) that Na extrusion is capable of generating an electrical potential, and (b) that increases in [Na](i) lead to reversible increases in P (Na) of muscle fibers. |
---|