SB-224289 (SB 224289) alone or in combination with cocaine, increases anxiety-like behavior. SB 224289 significantly reduces the amount of locomotor activity in the cocaine-treated rats. SB 224289-treated animals spend a significantly longer time in the corners than those treated with vehicle[2]. SB 224289 is a potent antagonist with an ED50 of 3.6 mg/kg, p.o in SK&F-99101-induced hypothermia in the guinea-pig. SB 224289 (4 mg/kg, p.o) reverses sumatriptan-induced inhibition of 5-HT release showing that it is also a potent terminal 5-HT autoreceptor antagonist in vivo. SB 224289 (2-16 mg/kg, p.o) does not increase 5-HT levels in the fuinea-pig frontal cortex. However, SB 224289 (4 mg/kg, p.o) causes a significantly increase in levels of 5-HT in the fuinea-pig dentate gyrus[3].
