Effects of dopamine D1 antagonists SCH23390 and SK&F83566 on locomotor activities in rats.

The effects of the dopamine D1 antagonists R-(+)-7-chloro-8-hydroxy-3-methyl-1phenyl-2,3,4,5-tetrahydro-1-H-3 -benzazapine (SCH23390) and (+-)-7-bromo-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1- H-3-benzazapine (SK&F83566) were tested for 2 h on linear locomotor, rearing, stereotypy, and margin times in an open field. Each of the antagonists attenuated the duration of linear locomotion, rearing, and stereotypy times in a dose- and time-dependent manner. The effectiveness of the antagonists was relatively brief and SCH23390 was more effective than SK&F83566 on each behavior. The two antagonists had differential effects on margin time.