tokens: Administration of graded doses of U-II ( 1 - 10 , 000 ng / mouse ) provoked :( 1 ) a dose - dependent reduction in the number of head dips in the hole - board test ;( 2 ) a dose - dependent reduction in the number of entries in the white chamber in the black - and - white compartment test , and in the number of entries in the central platform and open arms in the plus - maze test ; and ( 3 ) a dose - dependent increase in the duration of immobility in the forced - swimming test and tail suspension test .