Estrogen and estrogen-progesterone treatments counteract the effect of scopolamine on reinforced T-maze alternation in female rats

Behav Neurosci. 1994 Oct;108(5):988-92. doi: 10.1037//0735-7044.108.5.988.


The purpose of the experiments was to determine if steroid hormone treatments would attenuate the effect of the muscarinic receptor blocker scopolamine on a memory task. Ovariectomized rats were trained first to alternate for food reward between the arms of a T maze. Following training, females treated with scopolamine hydrobromide (0.2 mg/kg ip) did not alternate correctly between the arms of the T maze and responded at chance levels. However, when estradiol benzoate (25 micrograms) was administered 72, 48, and 24 hr before testing alone or in combination with progesterone (500 micrograms) administered 4-6 hr before testing, females alternated successfully between the arms of the T maze following scopolamine administration. Results indicate that gonadal steroids can completely counteract the impairment of T maze performance induced by scopolamine in female rats.

Publication types

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

MeSH terms

  • Animals
  • Appetitive Behavior / drug effects*
  • Estradiol / analogs & derivatives*
  • Estradiol / pharmacology
  • Female
  • Maze Learning / drug effects*
  • Memory, Short-Term / drug effects
  • Mental Recall / drug effects*
  • Orientation / drug effects*
  • Progesterone / pharmacology*
  • Rats
  • Reaction Time / drug effects
  • Receptors, Muscarinic / drug effects*
  • Scopolamine / antagonists & inhibitors*
  • Scopolamine / pharmacology


  • Receptors, Muscarinic
  • Progesterone
  • Estradiol
  • estradiol-17 beta-benzoate
  • Scopolamine