17884931

pubmed:Citation

Pt 1

Available evidence supports the idea that muscle fibres provide retrograde signals that enable the expression of adult motoneuron electrical properties but the mechanisms remain unknown. We showed recently that when acetylcholine receptors are blocked at motor endplates, the electrical properties of rat motoneurons change in a way that resembles changes observed after axotomy. This observation suggests that receptor blockade and axotomy interrupt the same signalling mechanisms but leaves open the possibility that the loss of muscle fibre activity underlies the observed effects. To address this issue, we examined the electrical properties of axotomized motoneurons following reinnervation. Ordinarily, these properties return to normal following reinnervation and re-activation of muscle, but in this study muscle fibre activity and evoked acetylcholine release were prevented during reinnervation by blocking axonal conduction. Under these conditions, the properties of motoneurons that successfully reinnervated muscle fibres recovered to normal despite the absence of muscle fibre activity and evoked release. We conclude that the expression of motoneuron electrical properties is not regulated by muscle fibre activity but rather by a retrograde signalling system coupled to activation of endplate acetylcholine receptors. Our results indicate that spontaneous release of acetylcholine from regenerated motor terminals is sufficient to operate the system.

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http://linkedlifedata.com/resource/pubmed/journal/0266262

http://linkedlifedata.com/resource/pubmed/chemical/Acetylcholine, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Cholinergic

Nov

pubmed-author:BichlerEdyta KEK, pubmed-author:CarrascoDario IDI, pubmed-author:CopeTimothy CTC, pubmed-author:PinterMartin JMJ, pubmed-author:RichMark MMM

15

NLM

47-56

pubmed-meshheading:17884931-Acetylcholine, pubmed-meshheading:17884931-Animals, pubmed-meshheading:17884931-Electromyography, pubmed-meshheading:17884931-Evoked Potentials, pubmed-meshheading:17884931-Female, pubmed-meshheading:17884931-Motor Endplate, pubmed-meshheading:17884931-Motor Neurons, pubmed-meshheading:17884931-Muscle, Skeletal, pubmed-meshheading:17884931-Rats, pubmed-meshheading:17884931-Rats, Wistar, pubmed-meshheading:17884931-Receptors, Cholinergic, pubmed-meshheading:17884931-Signal Transduction, pubmed-meshheading:17884931-Synaptic Transmission

Rat motoneuron properties recover following reinnervation in the absence of muscle activity and evoked acetylcholine release.

Journal Article, Research Support, N.I.H., Extramural