The effect of gamma-butyrolactone on locomotor activity in the rat.

The effect of gamma-butyrolactone (GBL) on locomotor activity in the rat was studied. Low doses of GBL (100 and 200 mg/kg) had a biphasic effect on activity. Initially, the activity of the rats was reduced, and this reduction was then followed by a period of hyperactivity. The effect of alpha-flupenthixol (50 microgram/kg alpha-FPT), atropine (10 mg/kg), benztroine (25 mg/kg), protriptyline (15 mg/kg), and clomipramine (25 mg/kg) was investigated on this biphasic effect. alpha-FPT reduced the hyperactivity while benztropine potentiated it; atropine, clomipramine, and protriptyline had little effect. It is concluded that the increase in activity could be due to a release of dopamine.