Effects of stress and of amphetamine on passive avoidance conditioning in rats

• Published in: General physiology and biophysics Vol. 24; no. 1; pp. 129 - 142
• Main Authors: Trnecková, L, Hynie, S, Sída, P, Hlinák, Z, Krejcí, I, Klenerová, V
• Format: Journal Article
• Language: English
• Published: Slovakia 01-03-2005
• Subjects: Amphetamines - administration & dosage; Animals; Avoidance Learning - drug effects; Conditioning (Psychology) - drug effects; Dose-Response Relationship, Drug; Hindlimb Suspension - methods; Immersion - physiopathology; Male; Rats; Rats, Wistar
• ISSN: 0231-5882

This study examined the effects of immobilization stress combined with water immersion (ICS) and/or amphetamine (AM) on different memory phases in the passive avoidance task in rats. The performance of rats was evaluated in the retention tests 24 and 48 h after a single acquisition trial. ICS exposure lasting 1 h impaired retention of the learned avoidance response if applied 2 to 4 h before or immediately after training. The stressor did not affect retrieval if presented 5 or 2 h before the retention test. AM was used i.p. at the dose of 8 or 1 mg/kg. Neither 8 mg AM administered 4 h before nor 8 or 1 mg doses given after training did not impair the retention performance in unstressed rats. The 1 mg AM prevented the impairment of retention in animals exposed to the stressor 3 or 4 h before training but had no effect when the stronger impairment was induced by ICS 2 h before training. However, when given 1 h before retention testing, 1 mg AM attenuated even the severe impairment induced by the pre-training stressor exposure. Our results suggest that ICS impairs primarily the early phase of memory consolidation and a low dose of AM can prevent this effect.