Neuropharmacological actions of enkephalin after systemic administration

Nicholas P. Plotnikoff, Abba J. Kastin, David H. Coy, Carl W. Christensen, Andrew V. Schally, Morris A. Spirtes

Research output: Contribution to journalArticlepeer-review

78 Scopus citations


A pentapeptide, methionine-enkephalin, which interacts with opiate receptors in the brain, was found to markedly potentiate the behavioral effects of DOPA when administered intraperitoneally into mice. These effects, which were even more striking with D-alanine-2-methionine-5-enkephalin but less with morphine, persisted at least two hours after systemic injection of the peptide. Only a weak effect of enkephalin was seen in a serotonin potentiation test. Systemic injections of enkephalin resulted in a significant reduction of footshock-induced fighting and slight reduction in audiogenic seizures in mice. The results suggest that the CNS effects observed after systemic administration of enkephalin may involve the dopaminergic receptor mechanism.

Original languageEnglish (US)
Pages (from-to)1283-1288
Number of pages6
JournalLife Sciences
Issue number8
StatePublished - Oct 15 1976
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)


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