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This Article Full Text Full Text (PDF) All Versions of this Article: 90/3/333    most recent expphysiol.2004.029132v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Desaulniers, P. Articles by Gardiner, P. F. Search for Related Content PubMed PubMed Citation Articles by Desaulniers, P. Articles by Gardiner, P. F.

¹ Departments of Kinesiology² Pharmacology, University of Montreal, C.P. 6128, Succursale Centre-Ville, Montreal, Canada³ Health, Leisure and Human Performance (HLHP) Research Institute and Spinal Cord Research Center, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2

Increased neuromuscular activity is known to provoke morphological and functional adaptations at the neuromuscular synapse. Most of these changes have been documented following endurance exercise training programmes. In this study, the effect of rat soleus muscle overload produced by tenotomy plus voluntary wheel-cage activity on neuromuscular transmission efficacy was investigated. The overload protocol increased miniature endplate potential (MEPP) and endplate potential (EPP) amplitudes by 17 and 19%, respectively (both P < 0.01), and increased MEPP frequency by 86% (P < 0.01). EPP amplitude rundown during continuous trains of activation was attenuated by 10% in the overloaded group (P < 0.01). Also, during intermittent activation, the overload protocol attenuated EPP amplitude rundown, mainly by enhancing EPP amplitude recovery by 10% during the quiescent periods (P < 0.01). Although the present results show that both the degree and direction of adaptation are similar to what has been observed at rat soleus neuromuscular junctions following an endurance training protocol, there are important nuances between the results, suggesting different mechanisms through which these changes may occur.

(Received 23 September 2004; accepted after revision 23 December 2004; first published online 7 January 2005)
Corresponding author Phillip F. Gardiner: Health, Leisure and Human Performance (HLHP) Research Institute and Spinal Cord Research Center, Max Bell Center, Room 307, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2. Email: gardine2{at}ms.umanitoba.ca