Neural Regen Res
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Review
Neuronal changes resulting in up-regulation of alpha-1 adrenoceptors after peripheral nerve injury.
Under normal conditions, the sympathetic neurotransmitter noradrenaline inhibits the production and release of pro-inflammatory cytokines. However, after peripheral nerve and tissue injury, pro-inflammatory cytokines appear to induce the expression of the alpha1A-adrenoceptor subtype on immune cells and perhaps also on other cells in the injured tissue. ⋯ Consequently, nociceptive afferents acquire an abnormal excitability to adrenergic agents, and inflammatory processes build. These mechanisms could contribute to the development of sympathetically maintained pain in conditions such as post-herpetic neuralgia, cutaneous neuromas, amputation stump pain and complex regional pain syndrome.