The septum and amygdala differentially mediate the anxiolytic effects of benzodiazepines

Brain Res. 1994 Feb 28;638(1-2):295-301. doi: 10.1016/0006-8993(94)90662-9.

Abstract

Microinfusions of a benzodiazepine anxiolytic (midazolam) into the septum or the amygdala suppressed different fear reactions in two tests of rat "anxiety". Septal infusions increased open-arm activity in the plus-maze test and decreased burying behavior in the shock-probe test whereas amygdaloid infusions produced neither of these antianxiety effects. Amygdaloid infusions, however, dramatically impaired shock-probe avoidance, an antianxiety effect not produced by the septal infusions. Infusions of the benzodiazepine receptor antagonist Ro 15-1788 (flumazenil) blocked each of these specific, anti-fear effects of midazolam without producing intrinsic effects by itself. These results suggest that benzodiazepine receptor systems within the amygdala and the septum differentially mediate specific fear reactions.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amygdala / drug effects
  • Amygdala / physiology*
  • Animals
  • Anxiety*
  • Avoidance Learning / drug effects*
  • Avoidance Learning / physiology
  • Brain / drug effects
  • Brain / physiology*
  • Flumazenil / pharmacology*
  • Infusions, Parenteral
  • Learning / drug effects*
  • Learning / physiology
  • Male
  • Midazolam / administration & dosage
  • Midazolam / pharmacology*
  • Organ Specificity
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Flumazenil
  • Midazolam