Abstract
This study examined the effect of prolonged inactivity, associated with aestivation, on neuromuscular transmission in the green-striped burrowing frog, Cyclorana alboguttata. We compared the structure and function of the neuromuscular junctions on the iliofibularis muscle from active C. alboguttata and from C. alboguttata that had been aestivating for 6 months. Despite the prolonged period of immobility, there was no significant difference in the shape of the terminals (primary, secondary or tertiary branches) or the length of primary terminal branches between aestivators and non-aestivators. Furthermore, there was no significant difference in the membrane potentials of muscle fibres or in miniature end plate potential (EPP) frequency and amplitude. However, there was a significant decrease in evoked transmitter release characterised by a 56% decrease in mean EPP amplitude, and a 29% increase in the failure rate of nerve terminal action potentials to evoke transmitter release. The impact of this suite of neuromuscular characteristics on the locomotor performance of emergent frogs is discussed.
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Abbreviations
- EPPs:
-
Evoked end plate potentials
- MEPPs:
-
Miniature end plate potentials
- NMJs:
-
Neuromuscular junctions
- RMP:
-
Resting membrane potential
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Acknowledgements
This work was supported by an Australian Research Council Large Grant to C.E.F. and a University of Queensland, Research and Development Grant to C.E.F. and N.L. N.J.H. wishes to acknowledge the Northcote Trust from which he received a generous postgraduate scholarship. The SV2 monoclonal antibody developed by Dr K.M. Buckley was obtained from the Developmental Studies Hybridoma Bank developed under the auspices of the NICHD and maintained by the University of Iowa, Department of Biological Sciences, Iowa City, IA 52242, USA. We declare that the experiments complied with the “Principles of animal care” publication No. 86–23, revised 1985, of the National Institute of Health, and also with current Australian laws.
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Hudson, N.J., Lavidis, N.A., Choy, P.T. et al. Effect of prolonged inactivity on skeletal motor nerve terminals during aestivation in the burrowing frog, Cyclorana alboguttata. J Comp Physiol A 191, 373–379 (2005). https://doi.org/10.1007/s00359-004-0593-5
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DOI: https://doi.org/10.1007/s00359-004-0593-5