Atropine, an anticholinergic drug, impairs memory retrieval of a high consolidated avoidance response in mice

Neurosci Lett. 2003 Jul 17;345(2):97-100. doi: 10.1016/s0304-3940(03)00493-2.


Immediate post-training intraperitoneal administration of the centrally acting anticholinesterase physostigmine (70.0, or 150.0 microg/kg) enhanced retention of male CF-1 mice tested 48 h after training in a one-trial step-through inhibitory avoidance task (0.8 mA, 50 Hz, 1 s footshock). The effect was observed in mice that received saline 30 min before the retention test; on the contrary, the pre-test administration of the centrally active muscarinic cholinergic antagonist, atropine (1.0 mg/kg, i.p.), but not methylatropine (1.0 mg/kg, i.p.), instead of saline, prevents the enhancement of retention induced by both doses of the anticholinesterase when given immediately after training. The high retention performance caused by post-training physostigmine was recovered following a second administration of the same doses of the drug, 10 min after the pre-test injections of atropine. Since, physostigmine do not influence memory retrieval when given prior to the retention test, and its post-training effects are not due to the induction of state-dependency, the recover of the high retention performance was probably due to a classical interaction between a muscarinic competitive antagonist and an indirect cholinergic agonist. Further, atropine probably does not modify the memory trace by erasing it, but by producing a poor retrieval.

Publication types

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

MeSH terms

  • Animals
  • Atropine / adverse effects*
  • Avoidance Learning / drug effects*
  • Behavior, Animal / drug effects
  • Cholinesterase Inhibitors / pharmacology
  • Dose-Response Relationship, Drug
  • Male
  • Memory Disorders / chemically induced*
  • Memory Disorders / psychology
  • Mice
  • Muscarinic Antagonists / adverse effects*
  • Physostigmine / pharmacology
  • Reaction Time / drug effects


  • Cholinesterase Inhibitors
  • Muscarinic Antagonists
  • Atropine
  • Physostigmine