The effect of α-amanitin on passive and active avoidance acquisition in mice

-Amanitin, a specific and potent inhibitor of form II DNA-dependent RNA polymerase, produced greater than 98% inhibition of the enzyme in mouse brain within 2 h of intracerebroventricular (icv.) injection. Mice were given one trial passive avoidance training and retested on the task 4 h later. Mice treated with -amanitin 2 h before training or immediately after training demonstrated a retention deficit when compared to non-injected or saline injected controls.Active avoidance was trained for 1 h using a Sidman schedule with a drumturning response. Performance during the last 15 min of training was compared to performance in the first 15 min of a retesting session, 4 h after training. -Amanitin, 2 h prior to training reduced the number of responses, per cent escapes and per cent avoidances in the retesting session. Post-training injection of -amanitin significantly reduced the number of responses and per cent avoidances.Rotarod and spontaneous motor activity were not affected by -amanitin. Whole body temperature was slightly and transiently reduced in icv. administration of -amanitin.