Evaluation of Na+/K+ pump function following repetitive activity in mouse peripheral nerve
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Evaluation of Na+/K+ pump function following repetitive activity in mouse peripheral nerve. / Moldovan, Mihai; Krarup, Christian.
In: Journal of Neuroscience Methods, Vol. 155, No. 2, 2006, p. 161-71.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Evaluation of Na+/K+ pump function following repetitive activity in mouse peripheral nerve
AU - Moldovan, Mihai
AU - Krarup, Christian
N1 - Keywords: Action Potentials; Animals; Dose-Response Relationship, Radiation; Electric Stimulation; Female; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Reaction Time; Sensory Thresholds; Tibial Nerve
PY - 2006
Y1 - 2006
N2 - After conduction of prolonged trains of impulses the increased Na+/K+ pump activity leads to hyperpolarization. The aim of this study was to develop a mouse model to investigate the Na+/K+ pump function in peripheral nerve by measuring the decrease in excitability during activity-dependent hyperpolarization. Acute electrophysiological investigations were carried out in seven adult mice. Nerve excitability was evaluated by tracking the change in threshold current after 5 min of 100 Hz stimulation of the tibial nerve at ankle. We developed a threshold tracking system that allowed us to follow several excitability measures simultaneously from the evoked plantar compound muscle action potential (CMAP) and sciatic compound nerve action potential (CNAP). Three minutes after repetitive supramaximal stimulation maximal CMAP and CNAP amplitudes recovered but the threshold was increased approximately 40% for motor axons approximately 34% for axons generating CNAP. The threshold recovered with a rate of 3.8%/minute that was similar for nerve and motor responses. By tracking the effect of polarizing currents we found evidence of activity dependent hyperpolarization, and our data suggest that the observed threshold change after repetitive stimulation of the mouse tibial nerve is an indicator of the Na+/K+ pump function in vivo. Evaluation of activity-dependent hyperpolarization may be an important indicator of axonal ability to cope with Na+ load.
AB - After conduction of prolonged trains of impulses the increased Na+/K+ pump activity leads to hyperpolarization. The aim of this study was to develop a mouse model to investigate the Na+/K+ pump function in peripheral nerve by measuring the decrease in excitability during activity-dependent hyperpolarization. Acute electrophysiological investigations were carried out in seven adult mice. Nerve excitability was evaluated by tracking the change in threshold current after 5 min of 100 Hz stimulation of the tibial nerve at ankle. We developed a threshold tracking system that allowed us to follow several excitability measures simultaneously from the evoked plantar compound muscle action potential (CMAP) and sciatic compound nerve action potential (CNAP). Three minutes after repetitive supramaximal stimulation maximal CMAP and CNAP amplitudes recovered but the threshold was increased approximately 40% for motor axons approximately 34% for axons generating CNAP. The threshold recovered with a rate of 3.8%/minute that was similar for nerve and motor responses. By tracking the effect of polarizing currents we found evidence of activity dependent hyperpolarization, and our data suggest that the observed threshold change after repetitive stimulation of the mouse tibial nerve is an indicator of the Na+/K+ pump function in vivo. Evaluation of activity-dependent hyperpolarization may be an important indicator of axonal ability to cope with Na+ load.
U2 - 10.1016/j.jneumeth.2005.12.015
DO - 10.1016/j.jneumeth.2005.12.015
M3 - Journal article
C2 - 16466807
VL - 155
SP - 161
EP - 171
JO - Journal of Neuroscience Methods
JF - Journal of Neuroscience Methods
SN - 0165-0270
IS - 2
ER -
ID: 21668358