sentence: SKF 81297 and quinpirole were from Tocris ( Minneapolis , MN , USA ) , dicyclomine , 6-OHDA-HCl , L-DOPA ( 3 - ( 3,4 - Dihydroxyphenyl-2 ,5,6 - d ) - L-alanine ) , desipramine , pargyline and benserazide were purchased from Sigma-Aldrich ( St. Louis , MO , USA ) .