Membrane constants and sodium conductance of a single muscle fibre

Ferroni, A; Blanchi, D; Meda, E

doi:10.1007/bf02139757

Cited by 5 publications

(3 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The estimation of membrane parameters for the smooth muscle cell is difficult, owing to the variable geometry of the cells and uncertainties about the position of the micro-electrode. The only conclusion that can be drawn from the present experiments is that the resistance of unit area of the smooth muscle membrane of the guinea-pig vas deferens may be of the same order of magnitude as that found for skeletal muscles (Boyd & Martin, 1959;Ferroni et al 1965).…”

Section: Discussionmentioning

confidence: 38%

“…If RM is assumed to be 1200 Q cm2, i.e. of similar magnitude to that found for cat tenuissimus (1430 Q£ cm2, Boyd & Martin, 1959) and guinea-pig abdominal muscle (500-1000 Q cm2, Ferroni, Blanchi & Meda, 1965), and if R*, the resistivity of the sarcoplasm, is 125 Q cm (Boyd & Martin, 1959), A would be equal to 250 ,u. R would then be between 29 and 41 MO, depending on the position of the microelectrode.…”

Section: Resultsmentioning

confidence: 86%

See 1 more Smart Citation

Electrical properties of the smooth muscle membrane of the guinea‐pig vas deferens

Hashimoto¹,

Holman²,

Tille³

1966

The Journal of Physiology

View full text Add to dashboard Cite

1. The effects of polarizing current on single smooth muscle cells of the isolated guinea‐pig vas deferens have been studied by means of a bridge circuit in which the same electrode was used to pass current and record membrane potential. 2. Most cells had polarization resistances from 15 to 37 MΩ. 3. Depolarizing currents caused graded spikes up to a maximum amplitude of 75 mV. 4. Self‐regenerative spikes occurred in some cells if the membrane was depolarized by > 35 mV. 5. Currents of long duration and sufficient intensity caused a repetitive discharge. 6. Spikes arising from excitatory junction potentials were always ‘all‐or‐none’ in contrast to the graded responses to intracellular stimulation. 7. Electrotonic potentials declined much more rapidly than spontaneous excitatory junction potentials (EJPs); thus the time course of the EJP cannot be determined by the passive electrical properties of the smooth muscle cell membrane.

show abstract

Section: Discussionmentioning

confidence: 38%

Section: Resultsmentioning

confidence: 86%

Electrical properties of the smooth muscle membrane of the guinea‐pig vas deferens

Hashimoto¹,

Holman²,

Tille³

1966

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…A normal RMP would be recorded as long as the microelectrode was inserted more than three space constants from the sarcolemma defect producing the depolarization. Space constants in cat and guinea-pig muscles have been estimated at 0-61-1-10 mm (Boyd & Martin, 1959;Ferroni, Blanchi & Meda, 1965). The fibres in our preparation were 8-3 mm long, so one would predict a 60-80% probability of recording a normal RMP in a fibre that actually had a localized depolarization originating from a single membrane defect.…”

Section: Discussionmentioning

confidence: 94%

Excitation failure in eccentric contraction‐induced injury of mouse soleus muscle.

Warren

Lowe

Hayes

et al. 1993

The Journal of Physiology

154

163

View full text Add to dashboard Cite

SUMMARY1. Histological evidence suggests that the force deficit associated with eccentric contraction-induced muscle injury is due to structural damage to contractile elements within the muscle fibre. Alternatively, the force deficit could be explained by an inability to activate the contractile proteins. It was the objective of this study to investigate the latter possibility.2. Mouse soleus muscles were isolated, placed in an oxygenated Krebs-Ringer buffer at 37°C, and baseline measurements were made. The muscle then performed one of three contraction protocols: (1) twenty eccentric (n = 10 muscles); (2) ten eccentric (n = 12); or (3) twenty isometric (n = 10) contractions. At the end of the injury protocol, measurements were made during performance of a passive stretch, twitch and tetanus. Next, force was recorded during exposure of the muscle to buffer containing 50 mm caffeine.3. Decrements in maximal isometric tetanic force (P0) observed for muscles in the twenty eccentric, ten eccentric, and twenty isometric contraction protocols were 42-6 + 4-2, 20-0 + 2-3 and 3.9 + 2-4 %, respectively. However, the caffeine-elicited forces in muscles from the three protocols were not different when corrected for initial differences in P0 (64X9 + 1X3, 64-2 + 2-1 and 68-9 + 2-5 % of pre-injury P0). The peak caffeine-elicited force was 118-4+8-6% of post-injury Po for the muscles in the twenty eccentric contraction protocol, which was significantly different from that observed for the other protocols (71-8-80-2 % post-injury P0). These findings indicate that the force deficit in this muscle injury model results from a failure of the excitation process at some step prior to calcium (Ca2+) release by the sarcoplasmic reticulum.4. In an attempt to locate the site of failure, intracellular measurements were made in injured muscles to test whether injury to the sarcolemma might have resulted in a shift of the resting membrane potential of the muscle fibre. However, microelectrode measurements of resting membrane potential for muscles in the twenty eccentric contraction protocol (-74-4 + 0-6 mV) were not different from muscles in the twenty isometric contraction protocol (-73-4+ 1-0 mV). These data suggest that membrane resting conductances were normal and are compatible with MS 1641 G. L. WARREN AND OTHERS the idea that the ability of the injured fibres to conduct action potentials was probably not impaired.

show abstract

Intracellular ion concentration and electrical activity in potassium-Depleted mammalian soleus muscle fibers

Akaike

1976

Pflugers Arch.

View full text Add to dashboard Cite

The relationship between the intracellular cation concentration and the membrane potential has been studied in "Na-rich" soleus muscle fibers of rats which had been fed a K-free diet for 10-50 days. The resting potentials of "Na-rich" muscle fibers closely agreed with the theoretical potential expected from ionic theory when a quantitative dissociation of active cation transport with Na ions extrusion exceeding K ions uptake was eliminated due to the recovery of "Na-rich" fibers in Krebs solution with 10 mM K for 2 h at 37 degrees C. The hyperpolarized membrane potentials during cellular Na ions extrusion were accounted for by the sum of the potentials produced by the electrogenic Na-pump and by the ionic diffusion potential. On the other hand, the amplitude of overshoot of action potentials decreased linearly with the logarithmic increase of the intracellular Na concentration ([Na]i). The maximum rate of rise of action potentials also changed as a fraction of [Na]i, though, at the early period of K-deficiency the inhibitory effect of the increased [Na]i on the maximum rate of rise was transiently masked by the hyperpolarization produced by the electrogenic Na-pump which secondarily led to a progressive reduction of Na inactivation, while the maximum rate of fall was a linear function of [K]i.

show abstract

Membrane constants and sodium conductance of a single muscle fibre

Cited by 5 publications

References 5 publications

Electrical properties of the smooth muscle membrane of the guinea‐pig vas deferens

Electrical properties of the smooth muscle membrane of the guinea‐pig vas deferens

Excitation failure in eccentric contraction‐induced injury of mouse soleus muscle.

Intracellular ion concentration and electrical activity in potassium-Depleted mammalian soleus muscle fibers

Contact Info

Product

Resources

About