The effect of a subchronic post-lesion treatment with (-)-deprenyl on the sensitivity of 6-OHDA-lesioned rats to apomorphine and d-amphetamine

The effects of a subchronic post-lesion treatment of 14 days with (-)-depre nyl or its solvent on the rotational response to apomorphine (0.1 mg/kg) an d d-amphetamine (2.5 mg/kg) in 6-OHDA- and SHAM-lesioned rats were investig ated. Rats received a local injection of 6-OHDA (g mu g/0.7 mu 1) or its so lvent into the medial forebrain bundle. Following the (SHAM or 6-OHDA) lesi on the animals were randomly assigned to one of the two post-lesion treatme nt groups, viz. vehicle or (-)-deprenyl (0.1 mg/kg, 2 x day, i.p.) and trea ted for 14 days. After a wash out period of 6 weeks the number of rotations in response to apomorphine (0.1 mg/kg) and d-amphetamaine (2.5 mg/kg) were compared. Seven days following the final behavioural experiments the anima ls were sacrificed and the striatal dopamine, DOPAC and HVA levels were det ermined. The (-)-deprenyl-treated 6-OHDA-lesioned rats responded with a red uced number of rotations in response to apomorphine but not to d-amphelamin e as compared to vehicle-treated 6OHDA-lesioned rats. However the two lesio n groups did not differ in striatal dopamine, DOPAC and HVA concentrations; the levels were below or close to the detection limit ipsilateral to the 6 -OHDA injections. Thus a post-lesion treatment with (-)-deprenyl reduced th e dopaminergic supersensitivity without a concomitant increase in striatal dopamine content. The data are discussed in the light of the previously des cribed neurorescue properties of (-)-deprenyl.