Membrane properties and calcium ion activity in skeletal muscle fibres of the dystrophic mouse
type: CreativeWork
description: The ReJI29 murine model of muscular dystrophy was employed to investigate the properties of skeletal muscle plasmalemma and calcium ion movements during muscle wastage, with the intention of determining the route of calcium influx, and the efficacy of calcium ion blockers in preventing this influx. Electrophysiological parameters (Resting membrane potential [RMP] and input resistance) reached adult magnitude in normal soleus and extensor digitorum longus (EDL) by 4 weeks and 3 weeks respectively. Electrophysiological parameters in dystrophic soleus developed in a similar maimer to normal muscle, but RMP in dystrophic EDL was reduced and input resistance was elevated suggesting the presence of a population of regenerating fibres. Twitch and contracture tension development reached mature levels by 4 weeks in normal soleus muscle, but development was prolonged to 10 weeks in EDL, due to the slower development of type II fibres. Contracture tension was markedly smaller in EDL possibly due to fibre type-related differences in the concentrations of calcium sequestering proteins.Twitch and contracture tension in dystrophic soleus was identical to normal. In dystrophic EDL, 4 week old muscle did not generate tension from either electrical or chemical stimulation. Older muscles generated tension but smaller than their normal counterparts. Twitch and contracture tomography revealed similarities between dystrophic EDL and immature normal EDL corroborating with the conclusions made from the electrophysiological experiments. Caffeine contractures generated in glycinerated normal soleus muscle, incubated in low calcium saline, and then bathed in high calcium saline reached 115-185% the magnitude of caffeine contractures generated prior to incubation. 4 week dystrophic soleus attained similar sized contractures, but contractures were reduced to 77-90% in older muscles. This technique was found to be inappropriate in the study of EDL. Caffeine contractures generated by normal soleu…
abstract: The ReJI29 murine model of muscular dystrophy was employed to investigate the properties of skeletal muscle plasmalemma and calcium ion movements during muscle wastage, with the intention of determining the route of calcium influx, and the efficacy of calcium ion blockers in preventing this influx. Electrophysiological parameters (Resting membrane potential [RMP] and input resistance) reached adult magnitude in normal soleus and extensor digitorum longus (EDL) by 4 weeks and 3 weeks respectively. Electrophysiological parameters in dystrophic soleus developed in a similar maimer to normal muscle, but RMP in dystrophic EDL was reduced and input resistance was elevated suggesting the presence of a population of regenerating fibres. Twitch and contracture tension development reached mature levels by 4 weeks in normal soleus muscle, but development was prolonged to 10 weeks in EDL, due to the slower development of type II fibres. Contracture tension was markedly smaller in EDL possibly due to fibre type-related differences in the concentrations of calcium sequestering proteins.Twitch and contracture tension in dystrophic soleus was identical to normal. In dystrophic EDL, 4 week old muscle did not generate tension from either electrical or chemical stimulation. Older muscles generated tension but smaller than their normal counterparts. Twitch and contracture tomography revealed similarities between dystrophic EDL and immature normal EDL corroborating with the conclusions made from the electrophysiological experiments. Caffeine contractures generated in glycinerated normal soleus muscle, incubated in low calcium saline, and then bathed in high calcium saline reached 115-185% the magnitude of caffeine contractures generated prior to incubation. 4 week dystrophic soleus attained similar sized contractures, but contractures were reduced to 77-90% in older muscles. This technique was found to be inappropriate in the study of EDL. Caffeine contractures generated by normal soleu…
author: Russell, Paul
language: en
keywords: F410 - Forensic science
date published: 1993-10
date modified: 2026-07-24T01:36:13Z
provider: University of Central Lancashire
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Central Lancashire