|
|
||||||||
1 Département de Kinésiologie, and 2 Département de Pharmacologie, Université de Montréal, Montréal, Québec, Canada H3C 3J7
Rat motor nerve terminals and the endplates they interact with exhibit changes to varying patterns of use, as when exposed to increased activation in the form of endurance exercise training. The extent to which these changes affect neuromuscular transmission efficacy is uncertain. In this study, the effects of habitual exercise on the electrophysiological properties of neuromuscular transmission in rat soleus muscle were investigated using a novel in situ approach. Consistent with previous reports, miniature endplate potential frequency was enhanced by habitual exercise. Other passive properties, such as resting membrane potential, miniature endplate potential amplitude, and "giant" miniature endplate potential characteristics were unaltered by the training program. Full-size endplate potentials were obtained by blocking soleus muscle action potentials with µ-conotoxin GIIIb. Quantal content values were 91.5 and 119.9 for control and active groups, respectively (P < 0.01). We also measured the rate and extent of endplate potential amplitude rundown during 3-s trains of continuous stimulation at 25, 50, and 75 Hz; at 50 and 75 Hz, we found both the rate and extent of rundown to be significantly attenuated (10-20%) in a specific population of cells from active rats (P < 0.05). The results establish the degree of activity-dependent plasticity as it pertains to neuromuscular transmission in a mammalian slow-twitch muscle.
motor activity; exercise; neuromuscular junction; synaptic transmission; endplate potential
This article has been cited by other articles:
![]() |
P. Gardiner, Y. Dai, and C. J. Heckman Effects of exercise training on {alpha}-motoneurons J Appl Physiol, October 1, 2006; 101(4): 1228 - 1236. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Desaulniers, P.-A. Lavoie, and P. F. Gardiner Effect of rat soleus muscle overload on neuromuscular transmission efficacy during continuous and intermittent activation Exp Physiol, May 1, 2005; 90(3): 333 - 340. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Gomez-Pinilla, Z. Ying, R. R. Roy, J. Hodgson, and V. R. Edgerton Afferent Input Modulates Neurotrophins and Synaptic Plasticity in the Spinal Cord J Neurophysiol, December 1, 2004; 92(6): 3423 - 3432. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Shiao, A. Fond, B. Deng, M. Wehling-Henricks, M. E. Adams, S. C. Froehner, and J. G. Tidball Defects in neuromuscular junction structure in dystrophic muscle are corrected by expression of a NOS transgene in dystrophin-deficient muscles, but not in muscles lacking {alpha}- and {beta}1-syntrophins Hum. Mol. Genet., September 1, 2004; 13(17): 1873 - 1884. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. van Lunteren and M. Moyer Wheel-running exercise alters rat diaphragm action potentials and their regulation by K+ channels J Appl Physiol, August 1, 2003; 95(2): 602 - 610. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |