Anales RANF

S1-01 OVEREXPRESSION OF P2X3 AND P2X7 RECEPTORS AND TRPV1 CHANNELS IN ADRENOMEDULLARY CHROMAFFIN CELLS IN A RAT MODEL OF NEUROPATHIC PAIN A.R. Artalejo 1 , M. Arribas-Blázquez 1 , L. Alcides Olivos-Oré 1 , M.V. Barahona 1 , M. Sánchez de la Muela 1 , V. Solar 1 , E. Jiménez 1 , J. Gualix 1 , J.M. McIntosh 2 , A. Ferrer- Montiel 3 , M.T. Miras-Portugal 1 1 . Universidad Complutense de Madrid. Madrid. Spain; 2 . University of Utah. Salt Lake City. Utah. USA; 3 . Universitas Miguel Hernández. Elche. Spain. We have tested the hypothesis that neuropathic pain acting as a stressor drives functional plasticity in the sympathoadrenal system. The relation between neuropathic pain and adrenal medulla function was studied with behavioral, immunohistochemical and electrophysiological techniques in rats subjected to chronic constriction injury of the sciatic nerve. In slices of the adrenal gland from neuropathic animals we have evidenced increased cholinergic innervation and spontaneous synaptic activity at the splanchnic nerve-chromaffin cell junction. Likewise, adrenomedullary chromaffin cells displayed enlarged acetylcholine-evoked currents with greater sensitivity to α -conotoxin RgIA, a selective blocker of α 9 subunit-containing nicotinic acetylcholine receptors, as well as increased exocytosis triggered by voltage-activated Ca 2+ entry. Altogether, these adaptations are expected to facilitate catecholamine output into bloodstream. Last, but most intriguing, functional and immunohistochemical data indicate that P2X3 and P2X7 purinergic receptors and TRPV1 channels are overexpressed in chromaffin cells from neuropathic animals. These latter observations are reminiscent of molecular changes characteristic of peripheral sensitization of nociceptors following the lesion of a peripheral nerve, and suggest that similar phenomena can occur in other tissues potentially contributing to behavioral manifestations of neuropathic pain. Funded by Spanish Minister Of Science And Innovation, grants BFU2011-26253 and BFU2015-70067-REDC to A.R.A., grants BFU2014-53654-P and BFU2015-70067- REDC to M.T. M-P, by Comunidad de Madrid, grant S2013/ICE-2958 to M.T. M-P., and by Areces Foundation, grant C-XVIII to M.T. M-P