Effect of restraint stress on food intake and body weight is determined by time of day

Igor I. Rybkin, You Zhou, Julia Volaufova, Gennady N. Smagin, Donna H. Ryan, Ruth Babette Harris

Research output: Contribution to journalArticle

138 Citations (Scopus)

Abstract

Three experiments were conducted to investigate the effect of restraint stress applied at different times of the light-dark cycle on feeding behavior and body weight of rats. Sprague-Dawley rats were restrained for 3 h in restraining tubes either at the start or the end of the light cycle. There was a significant reduction in food intake on the day of restraint and no change in food intake during a 10-day recovery period in either experiment. Reductions of food intake on the day of restraint were about the same for both restrained groups compared with their controls. When stress was applied in the evening, eating was inhibited during the first 2 h after restraint, whereas in rats restrained in the morning, feeding was suppressed twice: during the 4 h after restraint and during the first 2 h of the dark cycle. Restraint induced a significant weight loss that was greater in the rats stressed in the morning. Neuropeptide Y (NPY) levels determined at the time of food suppression for both experiments (beginning of the dark cycle) revealed an elevation of NPY in the paraventricular nucleus of rats stressed in the morning compared with other groups, but no difference in hypothalamic NPY mRNA expression. Expression of uncoupling protein mRNA in brown adipose tissue and leptin mRNA in epididymal fat, measured at the start of the dark period, was not altered by stress. There was an elevation of dopamine turnover in the hypothalami of rats restrained at the end of light cycle, but not those restrained in the morning. These results show that restraint stress has a greater effect on metabolism and energy balance when it is applied in the morning. Additional studies are needed to elucidate mechanisms involved in the suppression of food intake 9 h after restraint.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume273
Issue number5 42-5
StatePublished - Dec 16 1997
Externally publishedYes

Fingerprint

Eating
Body Weight
Neuropeptide Y
Photoperiod
Messenger RNA
Brown Adipose Tissue
Paraventricular Hypothalamic Nucleus
Feeding Behavior
Leptin
Energy Metabolism
Hypothalamus
Sprague Dawley Rats
Weight Loss
Dopamine
Fats
Food

Keywords

  • Leptin
  • Monoamines
  • Neuropeptide Y
  • Rats
  • Weight loss

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Effect of restraint stress on food intake and body weight is determined by time of day. / Rybkin, Igor I.; Zhou, You; Volaufova, Julia; Smagin, Gennady N.; Ryan, Donna H.; Harris, Ruth Babette.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 273, No. 5 42-5, 16.12.1997.

Research output: Contribution to journalArticle

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