Somatosensory & motor research
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Clinical Trial Controlled Clinical Trial
Quantification of deep and superficial sensibility in saline-induced muscle pain--a psychophysical study.
The aim of the present study was to study the sensibility in the area of saline-induced muscle pain. In three experiments, ten subjects were exposed to computer-controlled infusion of 0.5 ml isotonic (0.9%) or hypertonic (9%) saline into the anterior tibial muscle. The pain intensity was assessed on a visual analogue scale (VAS). ⋯ Moreover, the hypertonic saline infusion given on the second day produced significantly higher (130 +/- 50%) VAS scores than the infusion given on the first day. In experiment 3, the PT was determined in the subcutaneous tissue, but no significant effects of saline infusion were found. The present placebo-controlled experiments failed to show muscular or subcutaneous hyperalgesia after saline-induced muscle pain per se.
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Clinical Trial
"Warmth-insensitive fields": evidence of sparse and irregular innervation of human skin by the warmth sense.
Although more acute in some areas of the body than in others, temperature sensitivity is assumed to be present throughout the skin. Only when very small stimuli have been used (e.g., approximately 1 mm2) has sensitivity to warming or cooling appeared discontinuous. ⋯ The existence of such sites corroborates reports that warm fibers are rare in human cutaneous nerves and confirms the classical theory that cutaneous innervation by the warmth sense is punctate and sparse. The insensitive areas also provide unique opportunities for assessing the contribution of the low-threshold warmth system to perception of heat and heat pain, and their existence in healthy young adults contraindicates use of warmth sensitivity in neurological assessments of C-fiber function.