Effects of serum immunoglobulins from patients with complex regional pain syndrome (CRPS) on depolarisation-induced calcium transients in isolated dorsal root ganglion (DRG) neurons

摘要

Complex regional pain syndrome (CRPS) is thought to have an auto-immune component. One such target recently proposed from the effects of auto-immune IgGs on Ca2+ transients in cardiac myocytes and cell lines is the alpha 1-adrenoceptor. We have tested whether such IgGs exerted comparable effects on nociceptive sensory neurons isolated from rat dorsal root ganglia. Depolarisation-induced [Ca2+](i) transients were generated by applying 30 mM KCl for 2 min and monitored by Fura-2 fluorescence imaging. No IgGs tested (including 3 from CRPS patients) had any significant effect on these [Ca2+](i) transients. However, IgG from one CRPS patient consistently and significantly reduced the K+-induced response of cells that had been pre-incubated for 24 h with a mixture of inflammatory mediators (1 mu M histamine, 5-hydroxytryptamine, bradykinin and PGE2). Since this pre-incubation also appeared to induce a comparable inhibitory response to the alpha 1-agonist phenylephrine, this is compatible with the alpha 1-adrenoceptor as a target for CRPS auto-immunity. A mechanism whereby this might enhance pain is suggested. (C) 2015 Published by Elsevier Inc.