The effect of ions upon neuromuscular transmission in a herbivorous insect

Wood, David

doi:10.1113/jphysiol.1957.sp005841

Cited by 115 publications

(12 citation statements)

References 19 publications

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“…There is no evidence that this protection extends to the muscle fibres and it seems most likely that the muscular power output in response to a given rate of motor input is reduced when the fibres are bathed in media other than haemolymph. Neither the haemolymph substitute of Wood (1957) nor the high-sodium saline used here appeared to have been an adequate replacement, although the latter gives a longer lived and more active preparation.…”

Section: Walking Behaviour Of Intact and Operated Animalsmentioning

confidence: 72%

Motor output to the protractor and retractor coxae muscles in stick insects walking on a treadwheel

Graham

Wendler

1981

Physiological Entomology

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The motor output to the protractor and retractor mucles moving the coxa of the middle leg of Carausius morosus was recorded from the thoracic nerves during walking on a treadwheel. The leg movements on the wheel were generally similar to those found in free-walking animals, but tripod coordination was relatively independent of period, and the coordination of the adult animal on the wheel was most closely related to that found in free-walking first instars. The activity of a common inhibitor and four excitatory axons of the retractor and an excitatory axon of the protractor were followed for 850 steps (in six animals) to give a summary of the behaviour of the different units. The motor activity is less stereotyped than that previously reported for insects. There was strong reciprocity between the antagonists, but this was not directly correlated with the forward and backward movements of the legs. The first part of the stance phase of the leg was accompanied by a strong burst in the protractor nerve and relatively little retractor activity. This was followed by the main retractor burst which occupied the last 60% of the stance phase. The results are compared with motor output records of the locust and with earlier force-plate measurements on the stick insect. It must be concluded that the mesothoracic leg initially resists forward movement of the body introduction

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Section: Walking Behaviour Of Intact and Operated Animalsmentioning

confidence: 72%

Motor output to the protractor and retractor coxae muscles in stick insects walking on a treadwheel

Graham

Wendler

1981

Physiological Entomology

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“…Cooling had the largest effect on muscle E K and E Ca , which declined by 43 and 12mV, respectively. The absolute decline observed in E K would be sufficient to dissipate muscle membrane potential, as membrane potential closely follows E K in nonlepidopteran insects (Hoyle, 1953;Wood, 1957;Leech, 1986). In addition, the re-polarizing current of action potentials at the insect muscle membrane is generated by an outward potassium current, but unlike vertebrates, the rising phase is generated not by the movement of Na + but by an inward Ca 2+ current that is highly dependent on hemolymph [Ca 2+ ] (Hoyle, 1953;Patlak, 1976;Ashcroft, 1981;Collet and Belzunces, 2007 ] in the hemolymph can together explain the drop in resting potential and loss of excitability of insect muscle tissue that likely plays a role in both chill-coma onset and the progression of chilling injury (Esch, 1988;Hosler et al, 2000;Kostál et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

The role of the gut in insect chilling injury: cold-induced disruption of osmoregulation in the fall field cricket,Gryllus pennsylvanicus

MacMillan

Sinclair

2011

Journal of Experimental Biology

153

176

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SUMMARYTo predict the effects of changing climates on insect distribution and abundance, a clear understanding of the mechanisms that underlie critical thermal limits is required. In insects, the loss of muscle function and onset of cold-induced injury has previously been correlated with a loss of muscle resting potential. To determine the cause of this loss of function, we measured the effects of cold exposure on ion and water homeostasis in muscle tissue, hemolymph and the alimentary canal of the fall field cricket, Gryllus pennsylvanicus, during an exposure to 0°C that caused chilling injury and death. Low temperature exposure had little effect on muscle osmotic balance but it dissipated muscle ion equilibrium potentials through interactions between the hemolymph and gut. Hemolymph volume declined by 84% during cold exposure whereas gut water content rose in a comparable manner. This rise in water content was driven by a failure to maintain osmotic equilibrium across the gut wall, which resulted in considerable migration of Na + , Ca 2+ and Mg 2+ into the alimentary canal during cold exposure. This loss of homeostasis is likely to be a primary mechanism driving the cold-induced loss of muscle excitability and progression of chilling injury in chill-susceptible insect species.Supplementary material available online at

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“…In this respect, the moth muscle membrane is similar to that of several other insects. Hoyle (1953,1955) for locust and cockroach, Hagiwara & Watanabe (1954) for locust, Wood (1957Wood ( , 1963 for locust and stick insect, and Usherwood (1967) for locust and grasshopper, have demonstrated that the muscle cell membrane is predominantly permeable to K+. However, in all four of these insects, unlike the present experiments, and unlike those of Huddart (1966b) on various moths, the authors were able to demonstrate close to a 58 mV potential change for a tenfold increase in external K+.…”

Section: Restjltsmentioning

confidence: 99%

The resting potential of moth muscle fibre

Rheuben¹

1972

The Journal of Physiology

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SUMMARY1. The membrane of the moth muscle fibre was tested for resting permeability to various ions: it is not permeable to Mg2+ or Ca2+; it is slightly permeable to Na+ and NH4+; it is appreciably permeable to Cl-, but C1-is passively distributed; it is apparently permeable to H+ but effects of HCO3-are not ruled out; and it is primarily permeable to K+.2. Measurement of the internal K+ activity showed that E. is less negative than the resting potential.3. In the presence of DNP, or under anoxia, the membrane potential approaches, EKE; there is a small concomitant decrease in effective membrane resistance.4. An increase in external Ca2+ concentration is accompanied by increased effective membrane resistance and an increase in amplitude of the negative resting potential.5. Cooling the membrane (below room temperature) decreased the amplitude of the resting potential by 4-16 mV per 10°C, and was accompanied by a large increase in effective membrane resistance.6. The experimental results most readily fit the hypothesis that the resting potential of the moth muscle fibre, although the membrane is highly permeable to K+, Cl-and apparently to H+, is primarily maintained by an electrogenic transport process which generates an ionic current across the membrane. The possibility that the concentration gradient of H+ ions is metabolically maintained at a level sufficient to explain the resting potential was considered to be unlikely but could not be directly excluded.

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The effect of ions upon neuromuscular transmission in a herbivorous insect

Cited by 115 publications

References 19 publications

Motor output to the protractor and retractor coxae muscles in stick insects walking on a treadwheel

Motor output to the protractor and retractor coxae muscles in stick insects walking on a treadwheel

The role of the gut in insect chilling injury: cold-induced disruption of osmoregulation in the fall field cricket,Gryllus pennsylvanicus

The resting potential of moth muscle fibre

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