Model to explain post surgical and injury chronic pain

Discussion in 'Fibromyalgia Main Forum' started by tansy, Dec 18, 2005.

  1. tansy

    tansy New Member

    Sprouting phenomenon, a new model for the role of A-beta fibers in wind up.

    Med Hypotheses. 2005 Dec 12; [Epub ahead of print]

    Hoseini SS, Hoseini M, Gharibzadeh S.

    Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.

    PMID: 16356653


    Wind up is a progressive frequency-dependent facilitation of the responses
    of nociceptive neurons observed on the application of repetitive (usually
    electrical) stimuli of constant intensity. The NMDA and NK1 receptors are
    essentially involved in wind up.

    After induction of wind up, stimulation of C-fibers show the
    characteristics of wind up, but stimulation of Abeta fibers for induction
    of wind up is controversial.

    In this study, we have proposed a new model for the role of Abeta fibers in
    wind up, through sprouting of nerve fibers in the dorsal horn of spinal
    cord. We named it "sprouting phenomenon". It has been reported that in some
    clinical hyperalgesic states induced by peripheral injury or inflammation,
    wind up may aggravate the pain. For example, studies have indicated the
    presence of wind up in post-surgical states, some neuropathic pains,
    fibromyalgia syndrome, and post-herpetic neuralgia.

    According to sprouting phenomenon, it seems that some clinical
    interventions can be assessed to alleviate post-inflammatory pains: (1)
    Immediate and complete relief of inflammation by anti-inflammatory agents
    to prevent repetitive excitation of C-fibers and subsequent morphological
    changes of dorsal horn laminae; (2) using local anesthetics in order to
    prevent pain signal transmission; (3) prevention of sprouting by
    intrathecal injection of some anti-proliferation agents; (4) using NMDA or
    NK1 receptor antagonists to prevent central mechanism of wind up.

    Some clinical trials have indicated the effectiveness of these antagonists.
    It is worth noting that future clinical studies are needed to validate
    these predictions.