Effect of intracerebroventricular α-MSH on food intake, adiposity, c-Fos induction, and neuropeptide expression

Julie E. McMinn, Charles W. Wilkinson, Peter J Havel, Stephen C. Woods, Michael W. Schwartz

Research output: Contribution to journalArticle

131 Scopus citations

Abstract

α-Melanocyte-stimulating hormone (α-MSH) is a hypothalamic neuropeptide proposed to play a key role in energy homeostasis. To investigate the behavioral, metabolic, and hypothalamic responses to chronic central α-MSH administration, α-MSH was infused continuously into the third cerebral ventricle of rats for 6 days. Chronic α-MSH infusion reduced cumulative food intake by 10.7% (P < 0.05 vs. saline) and body weight by 4.3% (P < 0.01 vs. saline), which in turn lowered plasma insulin levels by 29.3% (P < 0.05 vs. saline). However, α-MSH did not cause adipose-specific wasting nor did it alter hypothalamic neuropeptide mRNA levels. Central α-MSH infusion acutely activated neurons in forebrain areas such as the hypothalamic paraventricular nucleus, as measured by a 254% increase in c-Fos-like immunore-activity (P < 0.01 vs. saline), as well as satiety pathways in the hindbrain. Our findings suggest that, although an increase of central melanocortin receptor signaling acutely reduces food intake and body weight, its anorectic potency wanes during chronic infusion and causes only a modest decrease of body weight.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume279
Issue number2 48-2
StatePublished - 2000

Keywords

  • Body weight
  • Hypothalamus
  • Melanocortin

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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