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Scripta Scientifica Medica

Temperature effects on simulated human internodal action potentials and their defining current kinetics

Stefan Krustev, Mariya Daskalova, Diana Stephanova

Abstract

PURPOSE: Action potentials reflect membrane properties in body excitable structures. To expand our studies on these membrane properties, the effects of temperature on internodal (paranodal, mid-internodal) action potentials and their defining current kinetics are investigated.

MATERIAL AND METHODS: The computations use our temperature dependent multi-layered model of human motor fibre and the temperature is increased in the range of 20-40ºC.

RESULTS: For all temperature dependent cases: (i) nodal, paranodal and mid-internodal action potentials are similar, with a small drop to minimal amplitude in the centre of the internode; (ii) transaxonal and trans myelin currents rapidly diminish in amplitude as the distance from the node increases reaching equal minimal values in the intermodal centre; (iii) the current kinetics of the paranodal and mid-internodal action potentials is slightly changed in the physiological range of 32-37ºC, and (iv) internodal ionic currents beneath the myelin sheath (INa, IKf, IKs, IRI, and ILk) are not temperature-dependent.

CONCLUSION: The effects of temperature on the paranodal and mid-internodal action potentials are the same as those on the nodal action potentials. However, the temperature effects on their current kinetics are quite different, because ion channels under the myelin are insensitive to the temperatures and short current impulses used in this study. The results obtained are important for the interpretation of temperature dependent nerve conduction measurements in health.

Scripta Scientifica Medica 2013; 45(4): 36-40.


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DOI: http://dx.doi.org/10.14748/ssm.v45i4.231

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About The Authors

Stefan Krustev
Medical University of Varna
Bulgaria

Mariya Daskalova
Bulgarian Academy of Sciences
Bulgaria

Diana Stephanova
Bulgarian Academy of Sciences
Bulgaria

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