Baclofen decreases somatic expression of mecamylamine-precipitated nicotine withdrawal in mice

VARANI A., GARCÍA BONELLI C. AND BALERIO G.

Buenos Aires

Congreso; XXXIX Reunión Anual de Comunicaciones Científicas. Sociedad Argentina de Farmacología Experimental; 2007

Sociedad Argentina de Farmacología Experimental

BACLOFEN DECREASES SOMATIC EXPRESSION OF MECAMYLAMINE-PRECIPITATED NICOTINE WITHDRAWAL IN MICE Varani A 1, Garcia Bonelli C1 and Balerio G1,2 1ININFA (CONICET) y 2Cát. de Farmacología (FFYB, UBA) Junín 956, 5°Piso.  Bs As E-mail: gbalerio@ffyb.uba.ar   Nicotine (NIC) is one of the active components of tobacco and play a major role in tobacco addiction. The aims of the present study were: a) to evaluate the possible role of GABAB receptor in NIC physical dependence; b) to analyze the neurochemical variations in various brain regions of mice  during NIC withdrawal syndrome and its prevention with baclofen (BAC, GABAB receptor agonist). Swiss-Webster albino mice received NIC (2.5 mg/kg, sc) four times daily, for 7 days. To precipitate NIC abstinence, dependent mice were injected with the nicotine antagonist mecamylamine (MEC, 2 mg/kg, ip) 1h after the last dose of NIC on the 8th day. A second group of dependent mice received BAC (2 mg/kg, ip) before MEC- precipitated abstinence. Somatic signs were measured for 30 min.  The levels of dopamine, serotonin and its metabolites were determined by HPLC in the striatum, cortex and hippocampus. BAC pre-treatment decreased the incidence of some NIC withdrawal signs, such as wet-dog-shakes (p<0.01) and paw tremors (p<0.001). The global withdrawal score was also attenuated by BAC (p<0.001). There were no differences in the monoamines and metabolites levels in the brain areas studied. These results indicate that BAC administration attenuates NIC withdrawal. This would not be related to changes in dopaminergic and serotonergic activity measured 30 min after MEC. Supported by UBACYT B021         Presentación: POSTER