5-HT(2C) receptor antagonists enhance the behavioural response to dopamine D(1) receptor agonists in the 6-hydroxydopamine-lesioned rat.

Non-dopaminergic therapies are of potential interest in the treatment of Parkinson's disease given the complications associated with current dopamine-replacement therapies. In this study we demonstrate that SB 206553 (5-methyl-1-(3-pyridylcarbamoyl)-1,2,3, 5-tetrahydropyrrol[2,3-f]indole) (20 mg/kg) enhanced the actions of the dopamine D(1) receptor agonist, SKF 82958 ((+)-6-chloro-7, 8-dihydroxy-3-allyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide) (1 mg/kg), in eliciting locomotion in the 6-hydroxydopamine-lesioned rat model of Parkinson's disease. This action was only seen following prior priming with L-DOPA (L-3, 4-dihydroxyphenylalanine). SB 206553 had no effect on rotational behaviour when given alone. 5-HT(2C) receptor antagonists may have potential as a means of reducing reliance on dopamine replacement in the treatment of Parkinson's disease.