The present study investigates the effects of gammavinylgaba (GVG, 4 days treatment at 50 and 200 mg/kg), a gabatransaminase inhibitor, on the high-voltage spindle (HVS) activity in control and nucleus basalis-lesioned rats. GVG treatment at 200 mg/kg, but not at 50 mg/kg increased HVS activity in controls. GVG greatly aggravated nucleus basalis magnocellularis (NBM) lesion-induced increase in HVS activity at 200 mg/kg, but not at 50 mg/kg. The present results demonstrate that partial NBM lesions increase the HVS inducing potency of GVG.