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Biphasic effect of acamprosate on NMDA but not on GABAA receptors in spontaneous rhythmic activity from the isolated neonatal rat respiratory network.
Pierrefiche O., Daoust M., Naassila M.
Neuropharmacology 47, 1 (2004) 35-45 - http://www.hal.inserm.fr/inserm-00746176
(15165832)
Biphasic effect of acamprosate on NMDA but not on GABAA receptors in spontaneous rhythmic activity from the isolated neonatal rat respiratory network.
Olivier Pierrefiche1, Martine Daoust1, Mickaël Naassila1
1 :  GRAP-JE - Groupe de Recherche sur l'Alcool & les Pharmacodépendances
http://www.u-picardie.fr/decouverte/sante/pagesliees/grap/accueilgrap.html
Université de Picardie Jules Verne
UFR Pharmacie, rue des Louvels 80000 Amiens
France
Acamprosate (calcium acetylhomotaurinate) has been shown to be effective in attenuating relapse in human alcoholics. The precise mechanism for acamprosate has been yet to be determined as there may be multiple sites of action for this drug. We investigated the mechanism of action of acamprosate on a spontaneous rhythmic activity recorded from hypoglossal nerve rootlet (XII) in neonatal rat brainstem slices. At 30 microM, acamprosate reversibly increased burst amplitude and reduced burst frequency, whereas at higher concentrations (100-400 microM) it induced a reversible and concentration-dependent inhibition of this activity. Interestingly, acamprosate (30 microM) enhanced the effects of low NMDA-induced excitation (1.5 microM), but inhibited higher NMDA-induced excitation (2.5, 5 microM) by 50-70%, demonstrating a differential effect on NMDA-induced excitation. Blockade of GABAA receptors did not affect the increase in amplitude of 30 microM acamprosate and partially abolished the inhibitory effects of 200 microM acamprosate. At 200 microM, acamprosate reduced high NMDA-induced excitation and abolished NMDA-evoked excitatory tonic phase, suggesting that excitatory effect of low concentrations of acamprosate mainly involved NMDA receptors, while the inhibitory effects at higher concentration included an increase in GABAA-mediated inhibition with a reduction of NMDA-mediated excitation. Consequently, combined blockade of both receptors abolished all effects of acamprosate tested at all concentrations. These results show that the effects of acamprosate are mediated via both GABAA and NMDA receptors and suggest a partial co-agonist role on NMDA receptors, at the level of a spontaneously active network.
Sciences du Vivant/Neurosciences
Anglais
0028-3908

Articles dans des revues avec comité de lecture
10.1016/j.neuropharm.2004.03.004
Neuropharmacology (Neuropharmacology)
Publisher Elsevier
ISSN 0028-3908 
internationale
07/2004
47
1
35-45

Aging – Alcohol Deterrents – Animals – Newborn – Hypoglossal Nerve – N-Methylaspartate – Rats – Sprague-Dawley – Receptors – GABA-A – N-Methyl-D-Aspartate – Respiratory Mechanics – Taurine