Behavioral effects of [4-Norleucine, 7-D-Phenylalanine]-α-melanocyte-stimulating hormone

Kristin Kobobun, Thomas L. O'Donohue, Gail E. Handelmann, Tomi K. Sawyer, Victor J. Hruby, Mac E. Hadley

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The behavioral effects of α-melanocyte stimulating hormone (α-MSH) were compared to an α-MSH analogue that had a norleucine substituted for methionine in the four position and a D-phenylalanine substituted for L-phenylalanine in the seven position. [Nle4,D-Phe7]-α-MSH has previously been shown to be a superpotent agonist on melanocytes [17]. The present experiments indicate that [Nle4,D-Phe7]-α-MSH is equipotent to α-MSH in inducing grooming when administered intraventricularly. In contrast, the analogue has the opposite effect of α-MSH on performance of a visual discrimination task. α-MSH improves visual performance whereas [Nle4,D-Phe7]-α-MSH attenuates such performance. The contrasting activities of [Nle4,D-Phe7]-α-MSH on the physiological processes described suggest that this analogue may interact with three distinct melanotropin receptors in different ways. On melanocyte receptors the melanotropin analogue is a superagonist, on CNS melanotropin receptors involved in grooming it is equipotent to α-MSH, and on CNS receptors involved in attention, learning and memory [Nle4,D-Phe7]-α-MSH may be an antagonist of endogenous melanotropin.

Original languageEnglish (US)
Pages (from-to)721-724
Number of pages4
Issue number5
StatePublished - 1983


  • Learning
  • Melanotropin receptors
  • Visual discrimination
  • [Nle,D-Phe]-α-MSH

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Endocrinology
  • Cellular and Molecular Neuroscience


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