The active sequence in the acth molecule responsible for inhibition of the extinction of conditioned avoidance behaviour in rats

Abstract

The effect of structural analogues of the N-terminal decapeptide of ACTH on inhibition of extinction of a conditioned avoidance response in rats has been studied. Studies involving the relation between chain length and behavioural activity revealed that the sequence 4–10 is the shortest peptide which affects the avoidance response as potently as does the decapeptide. Although the presence of the sequence 1–3 is not essential for the behavioural effect, slight structural modifications within these 3 amino acids are accompanied by loss of activity.