Estradiol increases the anorexia associated with increased 5-HT 2C receptor activation in ovariectomized rats

Heidi M. Rivera, Jessica Santollo, Larissa V. Nikonova, Lisa A. Eckel

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Estradiol's inhibitory effect on food intake is mediated, in part, by its ability to increase the activity of meal-related signals, including serotonin (5-HT), which hastens satiation. The important role that postsynaptic 5-HT 2C receptors play in mediating 5-HT's anorexigenic effect prompted us to investigate whether a regimen of acute estradiol treatment increases the anorexia associated with increased 5-HT 2C receptor activation in ovariectomized (OVX) rats. We demonstrated that intraperitoneal and intracerebroventricular (i.c.v.) administration of low doses of the 5-HT 2C receptor agonist meta-chlorophenylpiperazine (mCPP) decreased 1-h dark-phase food intake in estradiol-treated, but not oil-treated, OVX rats. During a longer feeding test, we demonstrated that i.c.v. administration of mCPP decreased 22-h food intake in oil-treated and, to a greater extent, estradiol-treated OVX rats. In a second study, we demonstrated that estradiol increased 5-HT 2C receptor protein content in the caudal brainstem, but not hypothalamus, of OVX rats. We conclude that a physiologically-relevant regimen of acute estradiol treatment increases sensitivity to mCPP's anorexigenic effect. Our demonstration that this same regimen of estradiol treatment increases 5-HT 2C receptor protein content in the caudal hindbrain of OVX rats provides a possible mechanism to explain our behavioral findings.

Original languageEnglish
Pages (from-to)188-194
Number of pages7
JournalPhysiology and Behavior
Volume105
Issue number2
DOIs
StatePublished - Jan 18 2012

Bibliographical note

Funding Information:
This work was supported by grants from the NIH : DK-073936 and MH-063932 (LAE), T32DC-00044 (HMR) and F31 NS-062667 (JS).

Keywords

  • Caudal brainstem
  • Estrogen
  • Food intake
  • MCPP
  • Serotonin

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Behavioral Neuroscience

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