The relationship between chloride ions and resting potential in skeletal muscle fibres of the locust and cockroach

1965 ◽  
Vol 15 (3) ◽  
pp. 303-312 ◽  
Author(s):  
D.W. Wood
Keyword(s):  
Skeletal Muscle ◽  
Chloride Ions ◽  
Resting Potential ◽  
Muscle Fibres ◽  
Skeletal Muscle Fibres ◽  
The Relationship

Different actions of calcium channel blocking agents on resting membrane conductance in developing skeletal muscle

1981 ◽  
Vol 59 (4) ◽  
pp. 335-341 ◽  
Author(s):  
C. M. Thomson ◽  
W. F. Dryden
Keyword(s):  
Skeletal Muscle ◽  
Inhibitory Action ◽  
Membrane Conductance ◽  
Myoblast Fusion ◽  
Resting Potential ◽  
Muscle Fibres ◽  
Calcium Channel Blocking Agents ◽  
Channel Blocking ◽  
Membrane Bound ◽  
Skeletal Muscle Fibres

The effects of Co2+, Mn2+, and La3+ (2 mM) and verapamil (5 × 10−6 M) on membrane conductance (Gm) and resting potential (Em) were studied in chick skeletal muscle fibres developing in culture. Cobalt and manganese had no effect on Gm at any time during myogenesis but verapamil caused a decrease in Gm in immature myotubes. This effect diminished with time and was absent by 3 days after myoblast fusion. Lanthanum caused an increase in Gm at all stages of development. All the agents studied caused a significant depolarization of Em. It is concluded that there is no resting calcium conductance in developing skeletal muscle but that there may be a resting sodium conductance which declines with maturation. Lanthanum may increase Gm by displacing membrane-bound calcium and destabilizing membrane structure. All the agents studied were thought to induce depolarization by an inhibitory action on (Na+ + K+)-ATPase.

scholarly journals Temperature Effects on Membrane Chloride Conductance and Electrical Excitability of Lizard Skeletal Muscle Fibres

1989 ◽  
Vol 144 (1) ◽  
pp. 551-563 ◽  
Author(s):  
BRETT A. ADAMS
Keyword(s):  
Skeletal Muscle ◽  
Neuromuscular Transmission ◽  
Threshold Current ◽  
Chloride Ions ◽  
Muscle Membrane ◽  
Muscle Fibres ◽  
Electrical Excitability ◽  
Ringer’S Solution ◽  
Single Nerve ◽  
Skeletal Muscle Fibres

1. Intracellular recording techniques were used to study the effects of temperature on resting membrane conductances, electrical excitability and synaptic efficacy in fast-glycolytic (FG) skeletal muscle fibres from the lizard Dipsosaurus dorsalis. 2. The conductance of the resting muscle membrane to chloride ions (gCl) increased from 488μS cm−2 at 15°C (pH7.8) to 730μS cm−2 at 45°C (pH7.4), yielding a temperature coefficient (thermal ratio, R10) of 1.14. Resting potassium conductance (gK) increased from 84μS cm−2 at 15°C to 236μScm−2 at 45 °C (R10=1.41). 3. Fibres bathed in Cl− -free Ringer's solution were hyperexcitable, and produced repetitive action potentials both during and following intracellular current injection. At the preferred body temperature of Dipsosaurus (near 40°C) the fibres also fired repetitively in response to single nerve shock. 4. The electrical excitability of Dipsosaurus fibres decreased with increasing temperature. Threshold current, measured at endplate regions of fibres bathed in normal Ringer's solution, was 146 nA at 15°C and 353 nA at 45°C (R10= 1.34). 5. Despite the temperature-dependent change in threshold current, at both 15 and 45°C all fibres examined had suprathreshold neuromuscular transmission response to single nerve shock. 6. The relative thermal independence of gCl in Dipsosaurus fibres may be an adaptation that contributes to a large safety factor for neuromuscular transmission at the high body temperatures preferred by this lizard species.

CRAYFISH SKELETAL MUSCLE REQUIRES BOTH INFLUX OF EXTERNAL Ca2+ AND Ca2+ RELEASE FROM INTERNAL STORES FOR CONTRACTION

1993 ◽  
Vol 181 (1) ◽  
pp. 95-105 ◽  
Author(s):  
H. Ushio ◽  
S. Watabe ◽  
M. Iino
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Sarcoplasmic Reticulum ◽  
Procambarus Clarkii ◽  
Isometric Tension ◽  
Resting Potential ◽  
Muscle Fibres ◽  
Flexor Muscle ◽  
Caffeine Treatment ◽  
Skeletal Muscle Fibres

The isometric tension and membrane potential of single skeletal muscle fibres from the flexor muscle of the carpopodite in the meropodite of crayfish Procambarus clarkii (Girard) were studied to determine whether crayfish muscle contraction requires Ca2+ release from the sarcoplasmic reticulum. Contraction elicited by brief extracellular electrical stimulation was reduced by the removal of Ca2+ or by the addition of 25 micromolar nicardipine in crayfish Ringer's solution. Addition of 30 micromolar ryanodine with 1 mmol l-1 caffeine induced a transient contracture, the peak tension of which was 10–30 % of that of the high-K+ induced contracture and which declined to the pretreatment level in 20–60 min. After ryanodine-caffeine treatment, 30 mmol l-1 caffeine failed to induce contraction, suggesting that intracellular Ca2+ stores had been exhausted by the treatment. Extracellular electrical stimulation also failed to induce contraction after ryanodine-caffeine treatment, although the resting potential was not changed. These results suggest that Ca2+ release from the sarcoplasmic reticulum, together with Ca2+ influx via nicardipine-sensitive Ca2+ channels, is essential to the contraction of crayfish leg muscle fibres after a brief membrane depolarization.

Sign in / Sign up

Export Citation Format

Share Document