Freezing of enkephalinergic functions by multiple noxious foci: a source of pain sensitization?

Autor: François Cesselin, Sylvie Bourgoin, Annie Mauborgne, Michel Hamon, Daniel Le Bars
Jazyk: angličtina
Rok vydání: 2009
Předmět:
Zdroj: PLoS ONE, Vol 4, Iss 9, p e6874 (2009)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0006874
Popis: BACKGROUND:The functional significance of proenkephalin systems in processing pain remains an open question and indeed is puzzling. For example, a noxious mechanical stimulus does not alter the release of Met-enkephalin-like material (MELM) from segments of the spinal cord related to the stimulated area of the body, but does increase its release from other segments. METHODOLOGY/PRINCIPAL FINDINGS:Here we show that, in the rat, a noxious mechanical stimulus applied to either the right or the left hind paw elicits a marked increase of MELM release during perifusion of either the whole spinal cord or the cervico-trigeminal area. However, these stimulatory effects were not additive and indeed, disappeared completely when the right and left paws were stimulated simultaneously. CONCLUSION/SIGNIFICANCE:We have concluded that in addition to the concept of a diffuse control of the transmission of nociceptive signals through the dorsal horn, there is a diffuse control of the modulation of this transmission. The "freezing" of Met-enkephalinergic functions represents a potential source of central sensitization in the spinal cord, notably in clinical situations involving multiple painful foci, e.g. cancer with metastases, poly-traumatism or rheumatoid arthritis.
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