Quantitative EEG and autonomic patterns of synthetic peptides related to dermorphin

The effects of dermorphin on EEG and autonomic variables are compared with the effects of 2 analogues and 2 homologues, all administered intracerebroventricularly in the rabbit. Dermorphin was the most effective in modifying all considered parameters: increase of cortically derived and calculated total power, bradycardia, respiratory depression and hypothermia. The dibenzylated heptapeptide was essentially inactive. The electrocortical pattern induced by the administration of L-dermorphin suggests a functional correlation between the amino acid D-ala 2 and the effects on EEG. Comparison between the effects produced by the N-terminal tetrapeptide and pentapeptide led us to hypothesize that amino acid Tyr 5 may be specifically involved in inducing the autonomic effects.