GABA(B) receptors involvement in the effects induced by nicotine on anxiety-related behaviour in mice.

The aim of the present study was to evaluate the possible involvement of GABA(B) receptors in the anxiolytic- and anxiogenic-like responses induced by nicotine in mice. Animals were exposed to nicotine only once. The acute administration of low (0.05mg/kg, sc) or high (0.8mg/kg, sc) doses of nicotine produced opposite effects in the elevated plus maze test; respectively, anxiolytic- and anxiogenic-like responses. The effect of pretreatment with either the GABA(B) receptor antagonist 2-OH-saclofen (0.25, 0.5 and 1mg/kg; ip) or the GABA(B) receptor agonist baclofen (0.5, 1 and 2mg/kg; ip), was evaluated on the anxiolytic- and anxiogenic-like responses induced by nicotine. 2-OH-saclofen completely abolished both nicotine-induced effects (p<0.001) at the highest dose tested, suggesting an involvement of GABA(B) receptors in these behavioural responses. On the other hand, baclofen failed to modify the anxiety-related effects of nicotine. These results suggest that the GABA(B) receptors are involved in the regulation of nicotine-induced anxiety-related behavioural responses in mice, and provide new findings to support a potential pharmaco therapeutic use of GABAergic drugs in the treatment of tobacco addiction.