Distractability under the influence of an ACTH 4-9 derivative

Event-related brain potentials, autonomic responses, and response latency under distraction conditions served to investigate the effects of an ACTH 4-9 derivative (ORG 2766) on attention. Male volunteers (45) received either 40 mg ORG 2766 or placebo in a double-blind setting. Two-stimulus trials with acoustic warning signal (S1) and acoustic S2 which had to be interrupted by immediate button press, preceded trials with distraction during the warning interval in 50% of the trials. A final period without distraction served to test for rebound effects. A reduction in early CNV was found in placebo subjects under distraction, while subjects under ORG 2766 showed no reduced early negativity, but increased late negativity under this condition. Peptide subjects differed from controls in evoked potential components, showing enhanced N1 and P3 amplitudes. Activity in the alpha band was elevated. Postexperimental systolic blood pressure was raised by 15 mm Hg under ORG 2766. Results are in agreement with previous findings and suggest ORG 2766 effects on distraction resistance and attention fixation.