Abstract: | In rats with unilateral 6-hydroxydopamine lesions of the substantia nigra, a specific D1 dopamine receptor agonist, SKF 38393A, at a dose that does not itself produce turning, significantly increased the contralateral rotation observed following a low dose of the specific D2 agonist LY 171555. Doses of SKF 38393A or the D2 agonist bromocriptine, which would themselves not induce turning, in combination produced a high rate of turning. These results suggest a synergistic interaction between D1 and D2 dopamine receptors in this system. |