Rotational responses to serotonergic and dopaminergic agonists after unilateral dihydroxytryptamine lesions of the medial forebrain bundle: co-operative interactions of serotonin and dopamine in neostriatum.

Rats with unilateral 5,7-DHT lesions, but not 5,6-DHT lesions, showed rotational responses to 5-HTergic drugs (5MeODMT and fenfluramine) that were qualitatively similar to those induced by DAergic drugs (apomorphine and amphetamine) after 6-OHDA lesions. However, 5,7-DHT-lesioned rats also themselves showed rotational responses to DAergic drugs. The merits and limitations of a unilateral 5,7-DHT-lesioned rotating rat model for studying 5-HTergic function are discussed. It is suggested that 5-HT and DA may function in a co-operative manner in the striatum. These findings may be important for the rational pharmacotherapy of Parkinson's disease in which 5-HT as well as DA has been shown to be substantially depleted.