Memory facilitation by post-training intraperitoneal, intracerebroventricular and intra-amygdala injection of Ro 5-4864

Brain Res. 1991 Mar 22;544(1):133-6. doi: 10.1016/0006-8993(91)90894-2.


Post-training i.p. (2.0 or 5.0 mg/kg), i.c.v. (2.5 micrograms/rat), or intra-amygdala (1.6-40 ng/amygdala) administration of Ro 5-4864 causes memory facilitation of step-down inhibitory avoidance in rats. The effect is expressed as an increased latency to step down in a retention test carried out 24 h after training. Ro 5-4864 is a blocker of the Cl(-)-channel associated with GABAA receptors, at a site sensitive to the antagonist, PK11195, and different from that sensitive to picrotoxin. PK11195, given i.c.v. (2.5 micrograms/rat) or into the amygdala (8 ng/amygdala), antagonized the effect of Ro 5-4864. Intra-amygdala picrotoxin administration (80 ng/amygdala) also caused retrograde memory facilitation, but its effect was not antagonized by PK11195. At a higher dose (40 ng/amygdala), PK11195 had an amnestic effect of its own, which suggests that it might be acting against an endogenous ligand of receptor to Ro 5-4864 in the Cl(-)-channel. These findings support the hypothesis that there is a GABAA mechanism in the amygdala normally involved in the modulation of the post-training memory processing of aversive learnings.

Publication types

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

MeSH terms

  • Amygdala / drug effects
  • Amygdala / physiology*
  • Animals
  • Avoidance Learning / drug effects*
  • Benzodiazepinones / administration & dosage
  • Benzodiazepinones / pharmacology*
  • Cerebral Ventricles / drug effects
  • Cerebral Ventricles / physiology*
  • Convulsants / pharmacology
  • Dose-Response Relationship, Drug
  • Electroshock
  • Injections, Intraperitoneal
  • Injections, Intraventricular
  • Isoquinolines / administration & dosage
  • Isoquinolines / pharmacology*
  • Male
  • Memory / drug effects*
  • Microinjections
  • Rats
  • Rats, Inbred Strains


  • Benzodiazepinones
  • Convulsants
  • Isoquinolines
  • 4'-chlorodiazepam
  • PK 11195