Intrahippocampal scopolamine impairs both acquisition and consolidation of contextual fear conditioning.
Lesions of the dorsal hippocampus have been shown to disrupt both the acquisition and the consolidation of memories associated with contextual fear (fear of the place of conditioning), but do not affect fear conditioning to discrete cues (e.g., a tone). Blockade of central muscarinic cholinergic receptor activation results in selective acquisition deficits of contextual fear conditioning, but reportedly has little effect on consolidation. Here we show for the first time that direct infusion of the muscarinic cholinergic receptor antagonist, scopolamine, into the dorsal hippocampus produces a dose-dependent deficit in both acquisition and consolidation of contextual fear conditioning, while having no impact on simple tone conditioning.
Wallenstein
G V
GV
Department of Psychology, University of Utah, Salt Lake City 84112, USA. g.wallenstein@m.cc.utah.edu
Vago
D R
DR
D000818:Animals; D003214:Conditioning, Classical / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005239:Fear; D005260:Female; D006624:Hippocampus / Q000378:metabolism*; D007858:Learning / Q000187:drug effects*; D008568:Memory / Q000187:drug effects; D018727:Muscarinic Antagonists / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011976:Receptors, Muscarinic / Q000187:drug effects; D012601:Scopolamine / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics
D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D012601:Scopolamine