Biomaterial Database

Secondary hyperalgesia to mechanical but not heat stimuli following a capsaicin injection in hairy skin. 1996

Z Ali, and R A Meyer, and J N Campbell

Department of Neurosurgery, Johns Hopkins University, Baltimore, MD 21287, USA.

A psychophysical investigation was carried out to examine whether heat hyperalgesia exists within the secondary mechanical hyperalgesia zone surrounding a capsaicin injection site on hairy skin. A non-contact laser stimulator was used to deliver temperature controlled stimuli to sites within and outside the zone of mechanical hyperalgesia. Heat testing was carried out before and after the intradermal injection of 50 micrograms of capsaicin into the volar forearm. The zones of mechanical hyperalgesia to punctate and stroking stimuli and the region of flare were also mapped after the capsaicin injection. Heat pain thresholds inside the secondary mechanical hyperalgesic zone were not significantly different from thresholds outside the secondary mechanical hyperalgesia zone. In addition, pain ratings to an ascending series of heat stimuli delivered inside the zone of secondary hyperalgesia were not significantly different from pain ratings outside the zone of secondary hyperalgesia. Thus, there was no evidence for heat hyperalgesia within the zone of secondary hyperalgesia to punctate mechanical stimuli. Though the areas of punctate and stroking hyperalgesia were correlated, no correlation existed between the magnitude of capsaicin evoked pain and the areas mechanical hyperalgesia to punctuate and stroking stimuli or the area of flare. This suggests that independent mechanisms may mediate evoked pain, central sensitization that leads to mechanical hyperalgesia, and axon reflexive flare.

UI	MeSH Term	Description	Entries
D007279	Injections, Subcutaneous	Forceful administration under the skin of liquid medication, nutrient, or other fluid through a hollow needle piercing the skin.	Subcutaneous Injections,Injection, Subcutaneous,Subcutaneous Injection
D011601	Psychophysics	The science dealing with the correlation of the physical characteristics of a stimulus, e.g., frequency or intensity, with the response to the stimulus, in order to assess the psychologic factors involved in the relationship.	Psychophysic
D002211	Capsaicin	An alkylamide found in CAPSICUM that acts at TRPV CATION CHANNELS.	8-Methyl-N-Vanillyl-6-Nonenamide,Antiphlogistine Rub A-535 Capsaicin,Axsain,Capsaicine,Capsicum Farmaya,Capsidol,Capsin,Capzasin,Gelcen,Katrum,NGX-4010,Zacin,Zostrix,8 Methyl N Vanillyl 6 Nonenamide,NGX 4010,NGX4010
D006197	Hair	A filament-like structure consisting of a shaft which projects to the surface of the SKIN from a root which is softer than the shaft and lodges in the cavity of a HAIR FOLLICLE. It is found on most surfaces of the body.	Fetal Hair,Hair, Fetal,Lanugo,Fetal Hairs,Hairs,Hairs, Fetal
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006930	Hyperalgesia	An increased sensation of pain or discomfort produced by minimally noxious stimuli due to damage to soft tissue containing NOCICEPTORS or injury to a peripheral nerve.	Hyperalgesia, Tactile,Hyperalgesia, Thermal,Hyperalgia,Hyperalgia, Mechanical,Hyperalgia, Primary,Hyperalgia, Secondary,Allodynia,Allodynia, Mechanical,Allodynia, Tactile,Allodynia, Thermal,Hyperalgesia, Mechanical,Hyperalgesia, Primary,Hyperalgesia, Secondary,Hyperalgesic Sensations,Mechanical Allodynia,Mechanical Hyperalgesia,Tactile Allodynia,Thermal Allodynia,Allodynias,Hyperalgesias,Hyperalgesias, Thermal,Hyperalgesic Sensation,Mechanical Hyperalgia,Mechanical Hyperalgias,Primary Hyperalgia,Primary Hyperalgias,Secondary Hyperalgia,Secondary Hyperalgias,Sensation, Hyperalgesic,Sensations, Hyperalgesic,Thermal Hyperalgesia
D000704	Analysis of Variance	A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.	ANOVA,Analysis, Variance,Variance Analysis,Analyses, Variance,Variance Analyses
D012867	Skin	The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.
D013314	Stress, Mechanical	A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.	Mechanical Stress,Mechanical Stresses,Stresses, Mechanical