Loss of GABA-B inhibition in the dorsal spinal cord of a neuropathic rat model

Abstract

Event Abstract Back to Event Loss of GABA-B inhibition in the dorsal spinal cord of a neuropathic rat model Sophie Laffray1, Marie-Amelie Papon1, Rabia Bouali-Benazzouz1, Alexandre Favereaux1, Yves Le Feuvre1, Ulo Langel1, Frédéric Nagy1 and Marc Landry1* 1 University Bordeaux 2, Pathophysiology of spinal neuronal networks, France Pathological states of neuropathic pain are related to sensitization of deep dorsal horn neurons that are likely to amplify nociceptive transmission, causing allodynia and hyperalgesia. The efficiency of GABAb agonists in the treatment of chronic pain is controversial. The present project aims to investigate possible dysfunction of GABAb inhibitory control of pain sensitization in the spinal cord of animal models. Our working hypothesis is that functional alteration of heterodimeric GABAb receptor depends on its dissociation, possibly triggered by intracellular partner proteins such as 14.3.3. We investigated the co-distribution of GABAb1 and 14.3.3 with microscopy techniques. The physical interactions between the various partner proteins have been studied with FRET / FLIM imaging and with co-immunoprecipitation approaches. The functional outcome of these interactions has been assessed in vitro with patch-clamp techniques, and in vivo with behavioural tests. Our results showed that in a rat neuropathic pain model, 14.3.3 expression is up regulated in the dorsal horn. GABAb receptor and 14.3.3 are codistributed in the same spinal neurons. The relative distribution of GABAb and 14.3.3 in spinal cord, investigated by electron microscopy, showed that the subcellular colocalization between GABAb1 and 14-3-3 is increased after spinal nerve ligation. Moreover, in cultures of spinal neuron, 14.3.3 overexpression resulted in a partial loss of colocalization between GABAb1 and b2 subunits, suggesting that 14.3.3 induced the dissociation of the GABAb receptor. A FRET-based imaging approach further confirmed the dynamic of 14.3.3-GABAb1 interactions in neurons. In COS cell culture; immunoprecipitation experiments demonstrated the physical association between 14.3.3 and GABAb1 subunit. Furthermore, it ensured the effects of 14.3.3 overexpression in disrupting the GABAb heterodimer. To reverse GABAb dysfunction in the dorsal horn, we designed different strategies based on siRNA-mediated 14.3.3 knockdown and on the use of synthetic peptides that block 14.3.3-binding site on GABAb1 subunit. The behavioural assessment of mechanical allodynia revealed that both strategies are efficient in potentiating the inhibitory effect of intrathecally injected Baclofen in neuropathic rats. By targeting associated proteins, it may thus be possible to improve the pharmacological efficiency of GABAb agonists in the treatment of neuropathic pain. Conference: 3rd Mediterranean Conference of Neuroscience , Alexandria, Egypt, 13 Dec - 16 Dec, 2009. Presentation Type: Oral Presentation Topic: Symposium 04 – Dis-inhibition processes in pain sensitization Citation: Laffray S, Papon M, Bouali-Benazzouz R, Favereaux A, Le Feuvre Y, Langel U, Nagy F and Landry M (2009). Loss of GABA-B inhibition in the dorsal spinal cord of a neuropathic rat model. Front. Neurosci. Conference Abstract: 3rd Mediterranean Conference of Neuroscience . doi: 10.3389/conf.neuro.01.2009.16.022 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Nov 2009; Published Online: 19 Nov 2009. * Correspondence: Marc Landry, University Bordeaux 2, Pathophysiology of spinal neuronal networks, Bordeaux, France, marc.landry@u-bordeaux.fr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sophie Laffray Marie-Amelie Papon Rabia Bouali-Benazzouz Alexandre Favereaux Yves Le Feuvre Ulo Langel Frédéric Nagy Marc Landry Google Sophie Laffray Marie-Amelie Papon Rabia Bouali-Benazzouz Alexandre Favereaux Yves Le Feuvre Ulo Langel Frédéric Nagy Marc Landry Google Scholar Sophie Laffray Marie-Amelie Papon Rabia Bouali-Benazzouz Alexandre Favereaux Yves Le Feuvre Ulo Langel Frédéric Nagy Marc Landry PubMed Sophie Laffray Marie-Amelie Papon Rabia Bouali-Benazzouz Alexandre Favereaux Yves Le Feuvre Ulo Langel Frédéric Nagy Marc Landry Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.