The effect of L-tryptophane upon the elaboration and extinction of a conditioned avoidance response and upon the behaviour of rats
Mager, P.; Klingberg, F.
Acta Biologica et Medica Germanica 31(6): 889-892
1973
ISSN/ISBN: 0001-5318 PMID: 4364678 Document Number: 58838
Twelve rats 6 months old which had free access to water and food were divided into 2 groups. The rats were trained to avoid a foot shock by alternating current by jumping on a hanging rod. The conditioned stimulus (CS) was switched on 3.5 sec before the unconditioned stimulus (UCS) and 10 combinations of UCS and CS were given for the first 6 days. From the 7th to the 9th day the CS alone was given. Reaction times and stay times were measured and the percentage of correct conditioned avoidance response (CAR) and of arrest reactions with dominating motivation were evaluated. L-Tryptophan 100 mg/kg was injected every day, 20 min before the conditioning, in one group and a 0.9% NaCl solution in the second group. Tryptophan impaired and retarded the elaboration of CAR. There was a significant difference between the groups on the third day which increased further from the 4th to the 9th day. Reaction times were significantly prolonged under tryptophan, from the 4th to 9th day, and a trend in reaction times existed in the control animals from the 2nd to the 6th day but only in the treated animals on the 5th day. Motor behaviour after application of tryptophan was complex. In the motivational situation the stay times amounted to 43% compared with the untreated group and the arrest reactions were decreased, but in the non-motivational situation the unconditioned and spontaneous motor responses were reduced.