Temperature dependence of excitability indices of human cutaneous afferents

Burke, David; Mogyoros, Ilona; Vagg, Rebecca; Kiernan, Matthew C.

doi:10.1002/(sici)1097-4598(199901)22:1<51::aid-mus9>3.0.co;2-q

Cited by 69 publications

(41 citation statements)

References 46 publications

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“…Chronaxie times where shorter than experimentally estimated times (refer to Table 1 in Wesselink et al 1999). It must be remembered, however, that the experimental values were estimated from compound fibre data (see for example studies by Burke et al 1999;, in contrast to the single fibre data presented here. Even so the chronaxie times compared favourably with times ranging from 113 to 202 µs from the Wesselink et al (1999) model.…”

Section: Discussionmentioning

confidence: 99%

“…Even so the chronaxie times compared favourably with times ranging from 113 to 202 µs from the Wesselink et al (1999) model. Different experimental studies on the effect of temperature on the chronaxie times in human cutaneous afferent nerve fibres show that chronaxie times do not vary significantly with a change in temperature (Mogyoros et al 1996;Burke et al 1999;Kiernan et al 2001). Simulated results from the present human nerve fibre model were in contrast to these findings, showing an increase of more than a factor 5 for a decrease in temperature from 37 to 20 • C (see Fig.…”

Section: Discussionmentioning

confidence: 99%

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Modelled temperature-dependent excitability behaviour of a generalised human peripheral sensory nerve fibre

Smit

Hanekom

2009

Biol Cybern

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The objective of this study was to determine if a recently developed human Ranvier node model, which is based on a modified version of the Hodgkin-Huxley model, could predict the excitability behaviour in human peripheral sensory nerve fibres with diameters ranging from 5.0 to 15.0 microm. The Ranvier node model was extended to include a persistent sodium current and was incorporated into a generalised single cable nerve fibre model. Parameter temperature dependence was included. All calculations were performed in Matlab. Sensory nerve fibre excitability behaviour characteristics predicted by the new nerve fibre model at different temperatures and fibre diameters compared well with measured data. Absolute refractory periods deviated from measured data, while relative refractory periods were similar to measured data. Conduction velocities showed both fibre diameter and temperature dependence and were underestimated in fibres thinner than 12.5 microm. Calculated strength-duration time constants ranged from 128.5 to 183.0 micros at 37 degrees C over the studied nerve fibre diameter range, with chronaxie times about 30% shorter than strength-duration time constants. Chronaxie times exhibited temperature dependence, with values overestimated by a factor 5 at temperatures lower than body temperature. Possible explanations include the deviated absolute refractory period trend and inclusion of a nodal strangulation relationship.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Modelled temperature-dependent excitability behaviour of a generalised human peripheral sensory nerve fibre

Smit

Hanekom

2009

Biol Cybern

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“…Rather, they function by rapidly cooling the skin, which slows initiation and conduction of impulses in cutaneous sensory nerves and increases their refractoriness. 102 Composed of volatile liquid refrigerants, vapocoolant sprays are applied to the skin at the site of the impending venous access procedure, and their rapid evaporation produces a short-lived (Ͻ1-minute) analgesic effect (see below). Because the effect is so transient, it may be more convenient in the clinic to use 2 providers, 1 to administer the spray, the other to carry out the venous access procedure itself.…”

Section: Vapocoolant Spraysmentioning

confidence: 99%

Pharmacologic Approaches for Reducing Venous Access Pain in Children

Zempsky

2008

Pediatrics

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A variety of pharmacologic options are available to clinicians who want to provide effective and safe topical local anesthesia to children undergoing venous access procedures. These options can be distinguished on the basis of how they deliver active drug through the impermeable outer layer of skin, the stratum corneum, to pain receptors located in the dermis and epidermis. Three general methodologies are typically used to bypass the stratum corneum: direct injection of local anesthetics, usually via a small-gauge hypodermic syringe; passive diffusion from topical creams or gels; and active needle-free drug strategies that enhance the rate of drug passage into the dermis and epidermis. Examples of the latter mechanisms include heatenhanced diffusion, iontophoresis, sonophoresis, laser-assisted transdermal passage, and pressurized gas delivery of powdered drug particles. Pharmacologic options in this setting can also be distinguished on the basis of the time to onset of full anesthetic effect. Several available agents induce significant local anesthesia within 1 to 3 minutes of administration, or faster, allowing easy integration into the skin preparation and subsequent venous access procedure. In combination with nonpharmacologic approaches, these agents can be used to dramatically lessen this significant source of pediatric pain. Pediatrics 2008;122:S140-S153

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“…In myelinated nerve fibres the total nodal I Na is subdivided into two functionally distinct currents, where the largest proportion (∼ 98%) has fast activating and inactivating kinetics (Burke et al 1999). Even though the HH model has a fast activating and inactivating I Na , when an action potential simulated at 25 • C was compared to a similar human nerve fibre action potential from the Schwarz et al 1995 study, the activation was too slow to describe the action potential rising phase in the human case.…”

Section: Parameters Applied To the Nodal Modelmentioning

confidence: 99%

“…Nerve fibre excitation behaviour is affected by temperature changes (Moore et al 1978;Burke et al 1999). Studies on human peripheral nerve fibres indicate an increase in action potential amplitude and duration, the absolute and relative refractory periods and chronaxie times when the temperature is decreased from 37 • C; while the rheobase current and conduction velocity decrease under the same temperature conditions (Buchthal and Rosenfalck 1966;Lowitzsch et al 1977;Kiernan et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Modelled temperature-dependent excitability behaviour of a single ranvier node for a human peripheral sensory nerve fibre

Smit

Hanekom

2008

Biol Cybern

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The objective of this study was to determine whether the Hodgkin-Huxley model for unmyelinated nerve fibres could be modified to predict excitability behaviour at Ranvier nodes. Only the model parameters were modified to those of human, with the equations left unaltered. A model of a single Ranvier node has been developed as part of a larger model to describe excitation behaviour in a generalised human peripheral sensory nerve fibre. Parameter values describing the ionic and leakage conductances, corresponding equilibrium potentials, resting membrane potential and membrane capacitance of the original Hodgkin-Huxley model were modified to reflect the corresponding parameter values for human. Parameter temperature dependence was included. The fast activating potassium current kinetics were slowed down to represent those of a slow activating and deactivating potassium current, which do not inactivate. All calculations were performed in MATLAB. Action potential shape and amplitude were satisfactorily predicted at 20, 25 and 37 degrees C, and were not influenced by activation or deactivation of the slow potassium current. The calculated chronaxie time constant was 65.5 micros at 37 degrees C. However, chronaxie times were overestimated at temperatures lower than body temperature.

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Temperature dependence of excitability indices of human cutaneous afferents

Cited by 69 publications

References 46 publications

Modelled temperature-dependent excitability behaviour of a generalised human peripheral sensory nerve fibre

Modelled temperature-dependent excitability behaviour of a generalised human peripheral sensory nerve fibre

Pharmacologic Approaches for Reducing Venous Access Pain in Children

Modelled temperature-dependent excitability behaviour of a single ranvier node for a human peripheral sensory nerve fibre

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