Jun 30, 2009

Peripheral nerve at extreme low temperatures 2: pharmacologic modulation of temperature effects

Cryobiology
K Baylor, M M Stecker

Abstract

Changes in temperature have profound and clinically important effects on the peripheral nerve. In a previous paper, the effects of temperature on many properties of the peripheral nerve action potential (NAP) were explored including the NAP amplitude, conduction velocity and response to paired pulse stimulation. In this paper, the effects of pharmacologic manipulations on these parameters were explored in order to further understand the mechanisms of these effects. The reduction in conduction velocity with temperature was shown to be independent of the ionic composition of the perfusate and was unaffected by potassium or sodium channel blockade. This implies that the phenomenon of reduced conduction velocities at low temperature may be related to changes in the passive properties of the axon with temperature. Blockade of sodium channels and chronic membrane depolarization produced by high perfusate potassium concentrations or high dose 4-aminopyridine impair the resistance of the nerve to hypothermia and enhance the injury to the nerve produced by cycles of cooling and rewarming. This suggests the possibility that changes in the sodium inactivation channel may be responsible for the changes in the NAP amplitude with temperature...Continue Reading

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Citations

Mentioned in this Paper

Neuro-Oncological Ventral Antigen 2
Nervousness
Calcium [EPC]
Physiologic Pulse
Structure of Sciatic Nerve
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SLC25A29 gene
Extracellular
Calcium
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