Locomotion in the rat after 5-hydroxy-L-tryptophan.

Previous work has shown that administration of 5HTP in amounts substantially less than those required to elicit 'serotonin syndrome' to rats pretreated witha peripheral decarboxylase inhibitor, produced increases in locomotion, measured by whole body movements. The purpose of the present work was to study the cyclic shifts of weights from side to side which underly the progress of locomotion and to see whether these change after 5HTP. From the reciprocal of the interval for one complete cycle was calculated the weight transferral frequency (WTF). The modal WTF for control and treated rats were in the ranges 1-1.49 and 2-2.49 Hz respectively, while the medians were in the ranges 2-2.49 and 2.5-2.99 Hz respectively. Testing of goodness of fit between the frequency distribution curves in control and treated animals showed significant differences. It is concluded that after 5HTP treatment, basic locomotor patterns are shifted towards higher frequencies.