Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.13/39633

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Title
Recording temperature affects the excitability of mouse superficial dorsal horn neurons, in vitro
Author/Creator
Graham, B. A.;  Brichta, A. M.;  Callister, R. J.
Institution
The University of Newcastle. Faculty of Health, School of Biomedical Sciences and Pharmacy
Description
Superficial dorsal horn (SDH) neurons in laminae I-II of the spinal cord play an important role in processing noxious stimuli. These neurons represent a heterogeneous population and are divided into various categories according to their action potential (AP) discharge during depolarizing current injection. We recently developed an in vivo mouse preparation to examine functional aspects of nociceptive processing and AP discharge in SDH neurons and to extend investigation of pain mechanisms to the genetic level of analysis. Not surprisingly, some in vivo data obtained at body temperature (37°C) differed from those generated at room temperature (22°C) in spinal cord slices. In the current study we examine how temperature influences SDH neuron properties by making recordings at 22 and 32°C in transverse spinal cord slices prepared from L3-L5 segments of adult mice (C57B1/6). Patch-clamp recordings (KCH₃SO₄ internal) were made from visualized SDH neurons. At elevated temperature all SDH neurons had reduced input resistance and smaller, briefer APs. Resting membrane potential and AP afterhyperpolarization amplitude were temperature sensitive only in subsets of the SDH population. Notably, elevated temperature increased the prevalence of neurons that did not discharge APs during current injection. These reluctant firing neurons expressed a rapid A-type potassium current, which is enhanced at higher temperatures and thus restrains AP discharge. When compared with previously published whole cell recordings obtained in vivo (37°C) our results suggest that, on balance, in vitro data collected at elevated temperature more closely resemble data collected under in vivo conditions.
Relation
Journal of Neurophysiology Vol. 99, Issue 5, p. 2048-2059
Publisher Link
http://dx.doi.org/10.1152/jn.01176.2007
Date
2008
Publisher
American Physiological Society
Keyword(s)
substantia gelatinosa neurons;  neocortical pyramidal neurons;  fiber evoked potentials;  long term potentiation;  patch clamp analysis;  membrane properties;  A-type;  adult rat;  lamina-I;  distinctive membrane
Resource Type
journal article
Identifier
http://hdl.handle.net/1959.13/39633
Identifier
ISSN:0022-3077
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Subject
"Journal of Neurophysiology"
 
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