Effects of an inhibitor of GABA-aminotransferase (gamma-vinyl-GABA) on the spatial navigation deficit induced by nicotinic blockade.

1. The present study investigated whether stimulation of the GABA-ergic system affects spatial navigation (water-maze, WM) deficit induced by nicotinic blockade (mecamylamine). 2. The effects of various doses of gamma-vinyl-GABA (GVG: 50, 150 and 300 mg/kg) and mecamylamine (2.5 and 10 mg/kg) were examined alone and in combination. 3. GVG at the dose 150 mg/kg alone did not impair the performance of rats in the WM task. 4. Mecamylamine at the dose 2.5 and 10 mg/kg clearly impaired the performance of rats in WM task. 5. When the two drugs were co-administered, no interaction between mecamylamine and GVG was observed. 6. Combined nicotinic and muscarinic blockade did not interact as well with GVG administration. 7. Our results do not provide support for any interaction between cholinergic and GABA-ergic mechanisms.