| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Departments of Neurology and Neuroscience, Case Western Reserve University School of Medicine, Louis Stokes Cleveland Veterans Affairs Medical Center, University Hospitals of Cleveland, Cleveland, Ohio 44106
Patch-clamp studies of mammalian skeletal muscle Na+ channels are commonly done at subphysiological temperatures, usually room temperature. However, at subphysiological temperatures, most Na+ channels are inactivated at the cell resting potential. This study examined the effects of temperature on fast and slow inactivation of Na+ channels to determine if temperature changed the fraction of Na+ channels that were excitable at resting potential. The loose patch voltage clamp recorded Na+ currents (INa) in vitro at 19, 25, 31, and 37°C from the sarcolemma of rat type IIb fast-twitch omohyoid skeletal muscle fibers. Temperature affected the fraction of Na+ channels that were excitable at the resting potential. At 19°C, only 30% of channels were excitable at the resting potential. In contrast, at 37°C, 93% of Na+ channels were excitable at the resting potential. Temperature did not alter the resting potential or the voltage dependencies of activation or fast inactivation. INa available at the resting potential increased with temperature because the steady-state voltage dependence of slow inactivation shifted in a depolarizing direction with increasing temperature. The membrane potential at which half of the Na+ channels were in the slow inactivated state was shifted by +16 mV at 37°C compared with 19°C. Consequently, the low availability of excitable Na+ channels at subphysiological temperatures resulted from channels being in the slow, inactivated state at the resting potential.
mammalian skeletal muscle; sodium channel; sodium current; fast inactivation; slow inactivation; paramyotonia congenita; hyperkalemic periodic paralysis
This article has been cited by other articles:
|
|
 |
|
  G. N. Filatov, M. J. Pinter, and M. M. Rich Role of Ca2+ in injury-induced changes in sodium current in rat skeletal muscle Am J Physiol Cell Physiol, August 1, 2009; 297(2): C352 - C359. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Carle, E. Fournier, D. Sternberg, B. Fontaine, and N. Tabti Cold-induced disruption of Na+ channel slow inactivation underlies paralysis in highly thermosensitive paramyotonia J. Physiol., April 15, 2009; 587(8): 1705 - 1714. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. A. Macdonald, O. B. Nielsen, and T. Clausen Effects of calcitonin gene-related peptide on rat soleus muscle excitability: mechanisms and physiological significance Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2008; 295(4): R1214 - R1223. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Cifelli, L. Boudreault, B. Gong, J.-P. Bercier, and J.-M. Renaud Contractile dysfunctions in ATP-dependent K+ channel-deficient mouse muscle during fatigue involve excessive depolarization and Ca2+ influx through L-type Ca2+ channels Exp Physiol, October 1, 2008; 93(10): 1126 - 1138. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Nordsborg, J. Ovesen, M. Thomassen, M. Zangenberg, C. Jons, F. M. Iaia, J. J. Nielsen, and J. Bangsbo Effect of dexamethasone on skeletal muscle Na+,K+ pump subunit specific expression and K+ homeostasis during exercise in humans J. Physiol., March 1, 2008; 586(5): 1447 - 1459. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. J. McKenna, J. Bangsbo, and J.-M. Renaud Muscle K+, Na+, and Cl disturbances and Na+-K+ pump inactivation: implications for fatigue J Appl Physiol, January 1, 2008; 104(1): 288 - 295. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. Buono, K. D. Ball, and F. W. Kolkhorst Sodium ion concentration vs. sweat rate relationship in humans J Appl Physiol, September 1, 2007; 103(3): 990 - 994. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Aughey, K. T. Murphy, S. A. Clark, A. P. Garnham, R. J. Snow, D. Cameron-Smith, J. A. Hawley, and M. J. McKenna Muscle Na+-K+-ATPase activity and isoform adaptations to intense interval exercise and training in well-trained athletes J Appl Physiol, July 1, 2007; 103(1): 39 - 47. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Shushakov, C. Stubbe, A. Peuckert, V. Endeward, and N. Maassen The relationships between plasma potassium, muscle excitability and fatigue during voluntary exercise in humans Exp Physiol, July 1, 2007; 92(4): 705 - 715. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. I. Vandenberg, A. Varghese, Y. Lu, J. A. Bursill, M. P. Mahaut-Smith, and C. L.-H. Huang Temperature dependence of human ether-a-go-go-related gene K+ currents Am J Physiol Cell Physiol, July 1, 2006; 291(1): C165 - C175. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Ulbricht Sodium Channel Inactivation: Molecular Determinants and Modulation Physiol Rev, October 1, 2005; 85(4): 1271 - 1301. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Nordsborg, M. Thomassen, C. Lundby, H. Pilegaard, and J. Bangsbo Contraction-induced increases in Na+-K+-ATPase mRNA levels in human skeletal muscle are not amplified by activation of additional muscle mass Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2005; 289(1): R84 - R91. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. K. Hansen, T. Clausen, and O. B. Nielsen Effects of lactic acid and catecholamines on contractility in fast-twitch muscles exposed to hyperkalemia Am J Physiol Cell Physiol, July 1, 2005; 289(1): C104 - C112. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Bouhours, S. Luce, D. Sternberg, J. C. Willer, B. Fontaine, and N. Tabti A1152D mutation of the Na+ channel causes paramyotonia congenita and emphasizes the role of DIII/S4-S5 linker in fast inactivation J. Physiol., June 1, 2005; 565(2): 415 - 427. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Aughey, C. J. Gore, A. G. Hahn, A. P. Garnham, S. A. Clark, A. C. Petersen, A. D. Roberts, and M. J. McKenna Chronic intermittent hypoxia and incremental cycling exercise independently depress muscle in vitro maximal Na+-K+-ATPase activity in well-trained athletes J Appl Physiol, January 1, 2005; 98(1): 186 - 192. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Nordsborg, M. Mohr, L. D. Pedersen, J. J. Nielsen, H. Langberg, and J. Bangsbo Muscle interstitial potassium kinetics during intense exhaustive exercise: effect of previous arm exercise Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2003; 285(1): R143 - R148. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-F. Desaphy, S. Pierno, C. Leoty, A. L. George Jr, A. De Luca, and D. C. Camerino Skeletal muscle disuse induces fibre type-dependent enhancement of Na+ channel expression Brain, June 1, 2001; 124(6): 1100 - 1113. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
O. M. Sejersted and G. Sjogaard Dynamics and Consequences of Potassium Shifts in Skeletal Muscle and Heart During Exercise Physiol Rev, October 1, 2000; 80(4): 1411 - 1481. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
