Anales RANF

S5-01 MODULATION OF NEURONAL GLYCINE TRANSPORT BY P2Y AND P2X RECEPTORS L. Villarejo-López 1,3 , E. Jiménez 1 , D. Bartolomé-Martín 1,4 , C. Aragón 1,2 , B. López- Corcuera 1,2 1 Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; 2 IdiPAZ-Hospital Universitario La Paz, Madrid, Spain; 3 Present address: Normon, S.A, Madrid, Spain; 4 Present address: Universidad de la Laguna, Tenerife, Spain. Glycinergic inhibitory neurons of the spinal dorsal horn exert critical control over the conduction of nociceptive signals to rostral brain areas. The high affinity sodium- and chloride-coupled glycine neurotransmitter transporters (GlyTs) control the availability of glycine at glycine-mediated synapses. GlyTs control intra and extracellular glycine concentrations in glycinergic (GlyT1 and 2) and glutamatergic (GlyT1) synapses and therefore, modulate glycine-mediated neurotransmission. GlyT1 and GlyT2 transport activity was differentially modulated by P2Y/13 receptors in rat brainstem and spinal cord primary cultures through a paracrine regulation mediated by NO. Here we monitored GlyT2 expression and transport upon pharmacological stimulation of P2X purinergic receptors in rat brainstem and spinal cord primary cultures combined with siRNA-mediated receptor knockdown and dorsal root ganglion cell enrichment to increase P2X expression. Spontaneous glycinergic currents, glycine release and GlyT2 uptake were concurrently measured in response to P2X receptor agonists. We found the stimulation of P2X purinergic receptors with βγ -methylene adenosine 5 ′ -triphosphate induces the up-regulation of GlyT2 transport activity by increasing plasma membrane expression and reducing transporter ubiquitination. We identified the receptor subtypes involved. Up-regulation of GlyT2 required the combined stimulation of homomeric P2X3 and P2X2 receptors or heteromeric P2X2/3 receptors. We proved the impact of P2X2/3 receptor activation on glycinergic neurotransmission involves the modulation of GlyT2 expression and activity. Moreover, we found GlyT2 expression is upregulated by many pro-nociceptive agents besides ATP. In conclusion GlyT2 is differentially modulated by P2Y receptors of suggested anti-nociceptive role and P2X2/3 receptors of recognized pro-nociceptive action promoting an opposite regulation of the transporter by ADP and ATP in nociceptive pathways. We propose this modulation has physio- pathological consequences in nociceptive signal conduction.