tokens: The therapeutic use of selective DA D1 receptor agonists such as SKF-82958 ( 6-chloro-7,8-dihydroxy-3-allyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzaze pine hydrobromide ) and A-77636 ( [1R, 3S] 3-[1'-admantyl]-1-aminomethyl-3,4-dihydro-5,6-dihydroxy-1H-2-benzo pyran hydrochloride ) seems limited because of their duration of action , which is too short for SKF-82958 (< 1 hr ) and too long for A-77636 (> 20 hr , leading to behavioral tolerance ). We therefore conducted the present acute dose - response study in four 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine ( MPTP )- exposed cynomolgus monkeys primed to exhibit levodopa - induced dyskinesias to evaluate the locomotor and dyskinetic effects on challenge with four doses ( from 0 .