Prior training and intermittent retraining attenuate pimozide-induced avoidance deficits

Area of Science:

• Neuroscience
• Behavioral Pharmacology

Background:

• Neuroleptics' effects on avoidance behavior are well-documented.
• The impact of prior training on these effects remains under-investigated.
• Pimozide is a neuroleptic affecting dopaminergic systems.

Purpose of the Study:

• To investigate the relationship between prior training and pimozide-induced avoidance deficits.
• To examine the effects of intermittent retraining on these deficits.

Main Methods:

• Experiment 1: Rats received varying prior training sessions before pimozide administration (0.5 or 1.0 mg/kg).
• Experiment 2: Assessed the impact of periodic retraining without pimozide on avoidance responding.
• One-way avoidance responding in rats was the primary behavioral measure.

Main Results:

• Prior training significantly increased resistance to pimozide's disruptive effects on avoidance behavior.
• Pretrained groups eventually showed impaired avoidance responding during continuous drug exposure.
• Periodic retraining reversed the cumulative disruptive effects of pimozide.

Conclusions:

• Dopaminergic systems are crucial for acquiring and maintaining operant response learning.
• Avoidance learning is impaired if initiated in untrained, drug-treated animals.
• Intermittent retraining can prevent the loss of avoidance responding in pretrained, drug-treated animals.