MK-212 monohydrochloride

Wistar (male, 200-290 g)^[2]

1.0 mg/kg; 2.0 mg/kg; 4.0 mg/kg

i.p.; single injection

Decreased the percentage of open-arm entries and the percentage of time spent in open arms at 2.0 mg/kg and 4.0 mg/kg doses compared to saline controls.
Decreased the absolute number of closed-arm entries at 4.0 mg/kg dose compared to saline controls.
Showed no significant effect on any measured parameter at 1.0 mg/kg dose.
Confirmed anxiogenic effects of 2.0 mg/kg and 4.0 mg/kg doses remained significant when controlling for closed-arm entries via ANCOVA.
Decreased the number of floor crossings from 78 in saline controls to 17 at 4.0 mg/kg dose compared to saline controls.
Decreased rearings from 18 in saline controls to 9 at 4.0 mg/kg dose compared to saline controls.
Showed no significant effect on either locomotor measure at 1.0 mg/kg and 2.0 mg/kg doses.
Decreased the percentage of open-arm entries and the percentage of time spent in open arms compared to saline-pretreated controls when paired with vehicle or 0.5 μg ritanserin microinfusions into the basolateral amygdala.
Had anxiogenic effect dose-dependently prevented by ritanserin microinfusions at doses of 1.25 μg, 2.5 μg, and 5.0 μg into the basolateral amygdala, with no significant differences between MK-212-pretreated and saline-pretreated groups at these higher ritanserin doses.