Optical evidence for a chloride conductance in the T-system of frog skeletal muscle
| Autor: | Juan Carlos del Valle, Judith A. Heiny, S. H. Bryant |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
medicine.medical_specialty
Cell Membrane Permeability Physiology Clinical Biochemistry Action Potentials Chloride Chlorides Physiology (medical) Internal medicine medicine Animals Repolarization Chemistry Muscles Cell Membrane Rana pipiens Electric Conductivity Temperature Skeletal muscle Conductance Biological Transport Electrophysiology Membrane Endocrinology medicine.anatomical_structure Biophysics GRENOUILLE medicine.symptom Muscle contraction medicine.drug |
| Zdroj: | Pfl�gers Archiv European Journal of Physiology. 416:288-295 |
| ISSN: | 1432-2013 0031-6768 |
| DOI: | 10.1007/bf00392065 |
| Popis: | T-system action potentials were recorded optically from intact frog skeletal muscle fibers stained with the non-penetrating potentiometric dye NK-2367. The effect of chloride removal on the falling phase of the radially propagating tubular action potential was studied to determine whether a chloride conductance located in the T-system membranes contributes to tubular repolarization during activity. Our results show that, in chloride-free Ringer, repolarization of the tubular action potential is significantly slowed. Moreover, the late phase of tubular repolarization is characterized by a large after-potential, which is highly temperature-dependent and appears as a secondary peak above 10 degrees C. The optical data were compared with predicted T-system action potentials generated from a radial cable equivalent circuit model of the T-system, in which the effects of a distributed tubular leak conductance were tested. Results of this analysis are consistent with the proposal that some of the outward repolarization current during the T-system action potential is drawn across a chloride conductance located in the T-system membranes. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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