Peripheral alpha-adrenoreceptors are involved in the development of capsaicin induced ongoing and stimulus evoked pain in humans
| Autor: | Per Hansson, Erik Kinnman, Eva-Britt Nygårds |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Adult
Male Sympathetic nervous system Injections Intradermal Injections Subcutaneous Pain chemistry.chemical_compound Phentolamine Physical Stimulation medicine Noxious stimulus Humans Adrenergic alpha-Antagonists Dysesthesia business.industry Middle Aged Receptors Adrenergic alpha Anesthesiology and Pain Medicine Allodynia medicine.anatomical_structure Nociception Neurology chemistry Capsaicin Regional Blood Flow Anesthesia Hyperalgesia Arm Female Neurology (clinical) medicine.symptom business Skin Temperature medicine.drug |
| Zdroj: | Pain. 69(1-2) |
| ISSN: | 0304-3959 |
| Popis: | While the sympathetic nervous system seems to be involved in some pain states, the mechanisms linking the sensory and sympathetic nervous system are unclear. In this study the possible involvement of peripheral alpha-adrenoreceptors in the development of capsaicin induced ongoing pain and mechanical hypersensitivity was examined in humans. Intradermal capsaicin injections in the volar aspect of the arm gave rise to ongoing burning pain and dysesthesia as well as mechanical hypersensitivity. Ongoing pain and pain evoked by von Frey filament stimulation was rated on a numerical rating scale after intradermal capsaicin injection. The area of skin in which von Frey filament stimulation evoked pain was measured. A subcutaneous injection of phentolamine (alpha-adrenoreceptor antagonist) on one side and saline on the other side prior to the capsaicin injection was done to evaluate the role of the peripheral alpha-adrenoreceptors in development of capsaicin induced sensory symptoms and signs. Significantly less ongoing and evoked pain developed on the phentolamine injected side compared to the saline side, the latter in the area adjacent to the capsaicin injection (primary zone) and well outside the area of flare (secondary zone). The area in which pain could be evoked on the phentolamine injected side was restricted to the area of flare and was significantly smaller than on the saline injected side. Mechanical stimulation gave rise to aftersensation and radiation of pain on the saline injected side in all subjects but only in one case on the phentolamine injected side. Peripheral alpha-adrenoreceptors thus seem to be involved in functional changes of primary afferents which contribute to ongoing pain and mechanical stimulus evoked pain. |
| Databáze: | OpenAIRE |
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