[Propranolol Impairs Memory Reconsolidation at Single and Multiple Paired with Tone Painful Electrocutaneous...

In the current paper there were used two methods for assessment of the propranolol effect on reactivated memory at reconsolidation phase--a classical pavlovian conditioning and the two-ways escape reflex. The difference between these two models was that in the first case a tone was paired with electrocutaneous painful stimulation only once, while in the second case it was applied multiply. Reminding was produced in the first case by placing the animals into the same context, whereas in the second case by application of the same amount of pairings of conditional and unconditional stimuli as it was used at the first day of learning. Propranolol reduced intensity of freezing reaction on 25% from the baseline at the classical conditioning approach and practically led to disappearance of memory and complete regress of the two-ways escape reflex. There was suggested on existence of the possible different mechanisms of noradrenergic blockade on memory loss at the stage of its reconsolidation in the used models of learning.