Reduced feeding response to neuropeptide Y in senescent Fischer 344 rats

Am J Physiol Regul Integr Comp Physiol. 2001 Apr;280(4):R1052-60. doi: 10.1152/ajpregu.2001.280.4.R1052.


The anorexia of aging syndrome in humans is characterized by spontaneous body weight loss reflecting diminished food intake. We reported previously that old rats undergoing a similar phenomenon of progressive weight loss (i.e., senescent rats) also display altered feeding behavior, including reduced meal size and duration. Here, we tested the hypothesis that blunted responsiveness to neuropeptide Y (NPY), a feeding stimulant, occurs concurrently with senescence-associated anorexia/hypophagia. Young (8 mo old, n = 9) and old (24-30 mo old, n = 11) male Fischer 344 rats received intracerebroventricular NPY or artificial cerbrospinal fluid injections. In response to a maximum effective NPY dose (10 microg), the net increase in size of the first meal after injection was similar in old weight-stable (presenescent) and young rats (10.85 +/- 1.73 and 12.63 +/- 2.52 g/kg body wt (0.67), respectively). In contrast, senescent rats that had spontaneously lost approximately 10% of body weight had significantly lower net increases at their first post-NPY meal (1.33 +/- 0.33 g/kg body wt (0.67)) than before they began losing weight. Thus altered feeding responses to NPY occur in aging rats concomitantly with spontaneous decrements in food intake and body weight near the end of life.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aging / physiology*
  • Angiotensin II / administration & dosage
  • Angiotensin II / pharmacology
  • Animals
  • Body Weight / drug effects
  • Cerebral Ventricles / drug effects
  • Cerebral Ventricles / physiology
  • Dose-Response Relationship, Drug
  • Energy Intake / drug effects
  • Feeding Behavior / drug effects*
  • Feeding Behavior / physiology
  • Humans
  • Injections, Intraventricular
  • Male
  • Neuropeptide Y / administration & dosage
  • Neuropeptide Y / pharmacology*
  • Rats
  • Rats, Inbred F344
  • Time Factors
  • Weight Gain / drug effects*
  • Weight Gain / physiology
  • Weight Loss / physiology


  • Neuropeptide Y
  • Angiotensin II