Baclofen-induced antinociception and nicotinic receptor mechanism(s)

In this study, the influences of nicotinic receptor agents on baclofen-indu ced antinociception in the tail-flick lest have been studied. Intraperitone al administration of baclofen (2.5, 5 and 10 mg/kg) to mice induced a dose- dependent antinociception in the tail-hick test. Subcutaneous injection of nicotine (0.5-2.5 mg/kg) also caused a dose-dependent antinociceptive respo nse. Intracerebral (10 and 20 mu g/mouse) but not intraperitoneal administr ation of hexamethonium (5 and 10 mg/kg) to mice decreased the response of b oth nicotine and baclofen. However, administration of the GABA(B) antagonis t CGP 35348 (100 and 200 mg/kg) decreased the response induced by baclofen but not by nicotine. It is concluded that at least part of the baclofen-ind uced antinociception may be mediated through a nicotinic mechanism.