Effects of baclofen on reserpine-induced vacuous chewing movements in mice
Fukushiro, D. F.
Silva, R. H.
Medrano, W. A.
Ribeiro, R. D.
Abilio, V. C.
Is part ofBrain Research Bulletin
MetadataShow full item record
We have described that GABA mimetic drugs present the ability to inhibit the expression of reserpine-induced oral movements. in this respect, oral movements is associated with important neuropathologies. This study investigates the effects of an acute or a repeated treatment of different doses of the GABA(B) agonist baclofen, as well as withdrawal from these treatments, on the development and/or expression of reserpine-induced vacuous chewing movements (VCM). Male mice received two injections of vehicle or of 1 mg/kg reserpine separated by 48h. in the first experiment, 24 h later, animals were acutely treated with vehicle or baclofen (1, 2 or 4 mg/kg). in the second experiment, animals were treated with vehicle or baclofen (1 or 4 mg/kg) for four consecutive days receiving a concomitant injection of 1 mg/kg reserpine (or vehicle) on Days 2 and 4. Twenty-four hours later, animals received vehicle or baclofen. Thirty minutes after the last injection, they were observed for quantification of VCM and open-field general activity. the acute administration of all the doses of baclofen abolished the manifestation of reserpine-induced VCM. Repeated treatment with 1 mg/kg baclofen induced tolerance to the ability of an acute injection of this dose to reduce VCM. Treatment with baclofen (4 mg/kg) did not modify spontaneous VCM. Acute administration of the highest dose induced a decrease in general motor activity and a potentiation of the reserpine-induced decrease in general activity. These results reinforce the involvement of GABAcrgic hypofunction in the expression of oral movements and suggest that a repeated treatment with baclofen induces compensatory changes in GABAergic transmission that can attenuate its acute property to decrease VCM. (c) 2005 Elsevier Inc. All rights reserved.
CitationBrain Research Bulletin. Oxford: Pergamon-Elsevier B.V., v. 68, n. 6, p. 436-441, 2006.
- EPM - Artigos