Excitation-contraction uncoupling in skeletal muscle by dantrolene sodium

Ellis, K. O.; Bryant, S. H.

doi:10.1007/bf00501011

Cited by 159 publications

(64 citation statements)

References 5 publications

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“…This is in contrast with the findings of Ellis & Bryant (1972) and of Bowman et al (1979) who observed that in the cat the time to peak is unaltered by dantrolene sodium. It can also be seen in Figure 2a that the mean rate of rise of tension was also reduced by dantrolene sodium, for both muscles.…”

Section: Resultscontrasting

confidence: 99%

“…Our results from rat muscle differ from previously reported results from cat muscle not only in the lesser differential effect of dantrolene sodium on fast and slow muscles but also in the effect of dantrolene sodium on the time to peak of the muscle twitch. Bryant (1972) andBowman et al (1979) found that dantrolene sodium had no effect on the time to peak in cat muscle; Figure 2b and d shows the reduction in Time (h) Figure 3 The immediate effect of a single intravenous injection of dantrolene sodium, and partial recoveries from same, on the maximum (normalized) tensions developed by EDL(a) and SOL(b) when stimulated at different frequencies (from top downwards: 200, 100, 75, 50, 25 and 10 Hz; the data shown by the open circles and dotted lines represent the tension developed in response to a single twitch stimulus given once every 10 s. The soleus preparation was clearly seen to fail some 7 to 8 h into the experiment; this was probably due to a failure of the blood supply to the muscle. Note that the EDL preparation was still viable at that time and was so for a further 3 h. time to peak produced by dantrolene sodium in rat muscle.…”

Section: Discussionmentioning

confidence: 99%

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THE ACTION OF DANTROLENE SODIUM ON RAT FAST AND SLOW MUSCLE in vivo

Leslie

Part

1981

British J Pharmacology

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1Rats, anaesthetized with urethane, were injected intravenously with dantrolene sodium in a carrier solution of 5% mannitol taken to pH 10 with NaOH. This carrier solution itself was without effect on extrafusal muscle contraction. 2 Dantrolene sodium (5 mg/kg) had a greater depressant action on the twitch contraction of the fast extensor digitorum longus (EDL) muscle than on the slow soleus (SOL) muscle. The EDL twitch was depressed to 25.9% + 1.2% (mean + s.e. mean, n = 7) of control whereas the SOL twitch was depressed to 31.3% + 0.4% (n = 9). These values are significantly different at the P<0.001 level. 3 The twitch contraction time to peak was reduced by approximately 35% in both EDL and SOL by dantrolene sodium. However, the drug reduced the half relaxation time of SOL by approximately 30% but that of EDL was hardly affected. 4 The effect of dantrolene sodium on contractions elicited by repetitive stimulation was dependent upon the stimulation frequency. For the SOL muscle the greatest depression was produced at a stimulation frequency of 25 Hz and for EDL at 75 Hz. The minimum of depression was produced for a full fused tetanus for both muscles. 5 The significance of these findings is discussed in terms of the action of dantrolene sodium on motor control in the intact animal.

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Section: Resultscontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 99%

THE ACTION OF DANTROLENE SODIUM ON RAT FAST AND SLOW MUSCLE in vivo

Leslie

Part

1981

British J Pharmacology

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“…This concentration of dantrolene has been shown to reduce the release of calcium from intracellular stores in skeletal muscle (7,10,28). This combination of low calcium and dantrolene blocked the turning response toward micropipette sources of 50 BU NGF/ml and/or 1 mM dB cAMP in all 30 growth cones tested (Table 111).…”

Section: Resultsmentioning

confidence: 90%

Characterization of the turning response of dorsal root neurites toward nerve growth factor.

Gundersen¹,

Barrett²

1980

The Journal of Cell Biology

471

185

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This study reports that chick dorsal root ganglion neurites undergo a rapid (20 min) reorientation of their direction of growth in response to nerve growth factor (NGF) concentration gradients in vitro. Dorsal root ganglia from chick embryos were explanted onto a collagen-poly-L-lysine substrate. After 24-48 h in culture, NGF gradients were applied to individual growth cones via a micropipette containing 50 biological units NGF/ml. The growth cones turned and grew toward these NGF sources. This turning response was not caused by the trophic effects of NGF on neurite initiation, survival, or growth rate. Dorsal root neurites also grew toward sources of mono- and dibutyryl cyclic adenosine monophosphate (dB cAMP), cyclic guanosine monophosphate (cGMP), and elevated calcium in the presence of the calcium ionophore A23187. These results are consistent with the hypothesis that intracellular levels of cAMP and /or cGMP and calcium may play a role in the turning response of dorsal root neurites toward NGF, but do not establish a causal relationship between the mechanisms of action of NGF, cyclic nucleotides and calcium. Total growth cone adherence to the substrate was measured using a timed microjet of perfusion medium. NGF increased the adherence of growth cones to the substrate, but caffeine and dB cAMP which also elicit the positive turning response, decreased growth cone adherence. Calcium, which did not elicit the positive turning response, produced a greater growth cone adherence to the substrate than that observed with NGF. Although these results do not rule out a role of adhesion changes in axonal turning to NGF, they show that a general increase in adherence does not correlate well with the rapid turning response observed in this study.

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“…Anaesthesia was supplemented with increments of 2.5 per cent thiopentone, as necessary. 4 Monitoring of both human and pigs included electrocardiogram, central venous pressure, blood pressure, heart rate, nasal, skin and rectal temperatures, skin colour, moisture and circulation, skeletal muscle tone, blood gases, serum electrolytes and enzymes.…”

Section: Pigsmentioning

confidence: 99%