Dose-dependent effect of gammahydroxybutyrate (GHB) on catalepsy in male mice

This study was designed to assess the effects of a single administration of four doses of gammahydroxybutyrate (GHB), a catabolite of GABA which has been proposed as a possible neurotransmitter or neuromodulator, on catalepsy in male mice. Catalepsy was measured by means of the bar test. An aluminium bar of 5 mm in diameter was placed 4 cm above the floor. The animals' forepaws were gently put on the bar and the time it took the animal to place at least one paw on the floor was measured. If 1 min elapsed without movement the test was interrupted. Successive behavioural evaluations of catalepsy were carried out 25 and 60 min after the administration of GHB or vehicle. The results show that GHB administration produced a dose-dependent increment of catalepsy in male mice. This action could be a GHB receptor-mediated specifically phenomenon or the result of a catalepsy response induced by a dopamine receptor activation.