The hyperpolarizing effect of hydrogen ions on transmembrane potential in frog skeletal muscle
| Autor: | S. L. Lee, G. W. Mainwood |
|---|---|
| Rok vydání: | 1968 |
| Předmět: |
Pharmacology
Membrane potential Hydrogen Physiology Chemistry Muscles Potassium Sodium chemistry.chemical_element General Medicine Frog skeletal muscle Carbon Dioxide Hydrogen-Ion Concentration Choline Membrane Potentials Ion chemistry.chemical_compound Biochemistry Physiology (medical) Animals Anura |
| Zdroj: | Canadian Journal of Physiology and Pharmacology. 46:151-157 |
| ISSN: | 1205-7541 0008-4212 |
| DOI: | 10.1139/y68-025 |
| Popis: | The transmembrane potential of frog sartorius fibers in normal Ringer's solution is increased by a few millivolts following a fall in pH of the external medium. The same result is observed in either a bicarbonate–CO2 or a phosphate buffer system. The hyperpolarizing response is still observed when sodium in the Ringer solution is replaced by choline. Immediately after increasing the external potassium from 2.5 to 10 meq/l this effect is reversed. On changing the external potassium back to 2.5 meq/l the effect returns and is considerably enhanced. Chloride loading by presoaking muscles in isotonic KCl and transferring to sucrose causes a reversal of membrane potential and leads to an exaggerated pH effect. These observations, together with the fact that transmembrane conductance falls at a lower pH, suggest that hydrogen ions act mainly by lowering PCl. When ECl > Em, hydrogen ions will increase transmembrane potential. This effect may form the basis of a local control mechanism by which cell activity and local metabolic conditions regulate transmembrane potential. |
| Databáze: | OpenAIRE |
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