Corticotropin-releasing hormone mediates alpha-melanocyte-stimulating hormone-induced anorexigenic action in goldfish

Peptides. 2008 Nov;29(11):1930-6. doi: 10.1016/j.peptides.2008.06.028. Epub 2008 Jul 8.

Abstract

alpha-Melanocyte-stimulating hormone (alpha-MSH) and corticotropin-releasing hormone (CRH) both suppress food intake, and the alpha-MSH- or CRH-signaling pathway has possible potency to mediate anorexigenic actions induced by most other neuropeptides in goldfish. Therefore, using specific receptor antagonists, we examined whether the anorexigenic actions of alpha-MSH and CRH mutually interact. The inhibitory effect of ICV injection of the alpha-MSH agonist, melanotan II (MT II), on food intake was abolished by treatment with a CRH 1/2 receptor antagonist, alpha-helical CRH((9-41)), whereas the anorexigenic action of ICV-injected CRH was not affected by treatment with a melanocortin 4 receptor antagonist, HS024. This led us to investigate whether alpha-MSH-containing neurons in the goldfish brain have direct inputs to CRH-containing neurons, using confocal laser scanning microscopy. alpha-MSH- and CRH-like immunoreactivities were distributed throughout the brain, especially in the diencephalon. alpha-MSH-containing nerve fibers or endings lay in close apposition to CRH-containing neurons in a region of the hypothalamus, the nucleus posterioris periventricularis (NPPv). These results indicate that, in goldfish, alpha-MSH-induced anorexigenic action is mediated by the CRH-signaling pathway, and that CRH plays a crucial role in the regulation of feeding behavior as an integrated anorexigenic neuropeptide in this species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Corticotropin-Releasing Hormone / pharmacology*
  • Eating / drug effects*
  • Female
  • Fluorescent Antibody Technique
  • Goldfish
  • Hypothalamus / chemistry
  • Injections, Intraventricular
  • Male
  • Melanocyte-Stimulating Hormones / pharmacology*
  • Peptide Fragments / pharmacology*
  • Peptides, Cyclic / pharmacology
  • alpha-MSH / analogs & derivatives
  • alpha-MSH / pharmacology

Substances

  • HS 024
  • Peptide Fragments
  • Peptides, Cyclic
  • alpha-MSH
  • MSH, 4-Nle-7-Phe-alpha-
  • Melanocyte-Stimulating Hormones
  • Corticotropin-Releasing Hormone
  • corticotropin releasing hormone (9-41)