Synthetic scotophobin: Analysis of behavioral effects on mice

Abstract

Scotophobin is a peptide previouslu identified [14] as the behaviorally active factor in brain extract of rats trained in passive dark avoidance. Mice injected intraperitoneally with a synthetic version of scotophobin or placebo were tested without reinforcement in a box with one dark and two white chambers. Scotophobin recipients spent less time than controls in the dark chamber. When strict precautions were taken against chemical degradation, the dose-response relationship remained stable for months and resembled that found by Ungar for natural scotophobin. A content analysis of all frequent mouse behaviors in the test apparatus delineated a more detailed scotophobin behavior pattern. Scotophobin elevated emotionally as measured by defecation rate when mice were locked in the dark box, but not when they were locked in a white or transparent box. The dark box as used in the original rat training situation produced the maximal drug induced avoidance effect. Avoidance was reduced by stimulus changes involving wall color, illumination, and the grid floor. Thus scotophobin induction of avoidance behavior as well as heightened emotionality appears to show stimulus specificity.