Aging impairs the control of prefrontal cortex on the release of corticosterone in response to stress and on memory consolidation

Neurobiol Aging. 2012 Apr;33(4):827.e1-9. doi: 10.1016/j.neurobiolaging.2011.06.011. Epub 2011 Jul 27.

Abstract

This study investigated the role of the dorsomedial prefrontal cortex (dmPFC) on the activity of the hypothalamus-pituitary-adrenal axis and memory consolidation in young and aged rats. The messenger RNA (mRNA) expression of several gamma-aminobutyric acid (GABA) and glutamate receptor subunits were also evaluated in the prefrontal cortex (PFC) of young and aged rats. Microinjections of picrotoxin (GABA(A) antagonist), muscimol (GABA(A) agonist), or vehicle were performed into the dmPFC of young adult (3 months) and aged (27 months) male Wistar rats. Plasma corticosterone was measured under acute stress (30-minute restraint) conditions following microinjections. The retention of an inhibitory avoidance response was also evaluated in response of the same treatments. Picrotoxin microinjections into the dmPFC reduced the stress-induced corticosterone concentrations on young but not on aged animals. Aging did not modify the mRNA content of any of the receptor subunits analyzed. Picrotoxin into the dmPFC reduced inhibitory avoidance response in young but not aged animals. Muscimol treatment did not modify any of the parameters evaluated. These results suggest that prefrontal cortex loses its capacity to control hypothalamo-pituitary-adrenal (HPA) axis activity and the consolidation of emotional memory during aging.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / physiology*
  • Analysis of Variance
  • Animals
  • Avoidance Learning / drug effects
  • Corticosterone / blood*
  • GABA Antagonists / pharmacology
  • GABA-A Receptor Agonists
  • Inhibition, Psychological
  • Male
  • Memory / drug effects
  • Memory / physiology*
  • Microinjections / methods
  • Muscimol / pharmacology
  • Picrotoxin / pharmacology
  • Prefrontal Cortex / drug effects
  • Prefrontal Cortex / physiology*
  • Rats
  • Rats, Wistar
  • Reaction Time / drug effects
  • Restraint, Physical / methods*
  • Time Factors

Substances

  • GABA Antagonists
  • GABA-A Receptor Agonists
  • Picrotoxin
  • Muscimol
  • Corticosterone