Depolarization accelerates the decay of K+ contractures in rat skeletal muscle fibers
| Autor: | Angela F. Dulhunty, Jorgen Mould, Michael F. Patterson |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Soleus muscle
Membrane potential Physiology Chemistry Skeletal muscle Depolarization Anatomy musculoskeletal system Extensor digitorum muscle Cellular and Molecular Neuroscience Electrophysiology medicine.anatomical_structure Physiology (medical) medicine Biophysics Neurology (clinical) Contracture medicine.symptom tissues Muscle contracture |
| Zdroj: | Muscle & Nerve. 19:1025-1036 |
| ISSN: | 1097-4598 0148-639X |
| DOI: | 10.1002/(sici)1097-4598(199608)19:8<1025::aid-mus10>3.0.co;2-w |
| Popis: | The experiments examine the effects of membrane potential on the time course of K+ contractures in small bundles of rat soleus and extensor digitorum longus (EDL) muscle fibers. Control K+ contractures were induced by exposure to a 200 mmol/L K+ solution in polarized fibers with a resting membrane potential of −83 mV (3.5 mmol/L K+), while test contractures were evoked with 200 mmol/L K+ from −46 mV, after 5, 10, and 30 min in a 30 mmol/L K+ conditioning solution. The decay times of the test K+ contracture in depolarized fibers were faster than those of the control K+ contracture in both soleus and EDL. A maximum reduction of 60% in the time for the contracture to decay from 90% to 10% was seen in soleus fibers after depolarizations lasting 10 min, while a reduction of 45% was seen in the decay time of EDL fibers after a 5-min depolarizations. The amplitudes of the test contractures were 30% less than control after 5-min and 10-min depolarization and 50% less than control after 30 min. Analysis of the results suggests that the kinetics of excitation-contraction coupling may be altered in damaged muscle fibers. © 1996 John Wiley & Sons, Inc. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text