programa - XIV Congreso Nacional de la Sociedad Española de ...

Reunión Científica Red de Trastornos Adictivos-CIBERSAMSalamanca 27 y 28 de septiembre de 2011O19. LOSS OF THE HINT1 PROTEIN REVEALS THE NMDAR-SENSITIVE COMPONENT OF WIN55,212-2INDUCED ANALGESIAP. Sánchez-Blázquez 1,2 , A. Vicente-Sánchez 1,2 , M. Rodriguez-Muñoz 2 , E. Berrocoso 2,3 and J. Garzón 1,21Instituto Cajal, CSIC, Avda Dr. Arce 37, 28002 Madrid.2Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, ISCIII, Madrid.3Department of Neuroscience, Faculty of Medicine, University Cadiz, 11003 Cadiz.Introduction. HINT1 is a member of the histidine triad superfamily of nucleotide hydrolases and transferases.The dimers formed by the HINT1 protein contain a cluster of zinc-binding histidine residues and a strong negativecharge both of which facilitate its interaction with other proteins. This suggests that HINT1 might act as a scaffoldprotein in G protein coupled receptor signalling. Indeed, we have shown that HINT1 is essential to maintain theconnection between the N-methyl-D-aspartate receptors (NMDAR) and the mu opioid receptor in the mouse brain(1). Notably, NMDA receptor stimulation is required for cannabinoid-induced analgesia.Hypothesis. The purpose of this study was to evaluate the possible role of HINT1 in the molecular processesunderlying the connection between CB1R and the NMDAR.Methods. Knockout mice on a 129SvJ background were used in this study in which the HINT1 gene is disrupted.The genotype of the mice was confirmed by PCR analysis of DNA extracted from tail biopsies and the responseof the animals to nociceptive stimuli was determined by the warm water (52°C) tail-flick test.Results. Intracerebroventricular administration of the cannabinoid agonists, WIN 55,212-2 and methanandamideproduced a similar dose-dependent analgesic response in WT and HINT1-KO mice. Likewise, the development ofacute tolerance was similar in both WT and HINT1-KO mice. However, pre-treatment with dizocilpine (MK-801), acompetitive antagonist of the NMDA receptor, blocked the analgesia induced by the cannabinoid in WT mice butnot in KO mice. Moreover, in the absence of HINT1 the CB1R became supersensitive, developing a profound andlasting desensitization.Conclusion. HINT1 is required for the NMDA receptor to regulate the analgesic activity of cannabinoids.Supported by FIS/PI08-0417 and FIS-PS09/00332 grants from the ISCIII, MICINN/FEDER.1 Rodríguez-Muñoz M, et al. (2010). Cell Mol Life Sci doi 10.1007/s00018-010-0598-x (online 14 December2010).Página 28 de 41