Scopolamine selectively disrupts the acquisition of contextual fear conditioning in rats.
Muscarinic cholinergic antagonism produces learning and memory deficits in a variety of hippocampal-dependent tasks. Hippocampal lesions produce both acquisition deficits and retrograde amnesia for contextual fear conditioning, but do not impact fear conditioning to discrete cues. In order to examine the effects of muscarinic antagonism in this paradigm, rats were given scopolamine (1 mg/kg) either before or for 3 days after a Pavlovian fear-conditioning session in which tones were paired with aversive footshocks. Fear to the context and the tone was assessed by measuring freezing in separate tests. It ws found that pretraining, but not posttraining, scopolamine severely impaired contextual fear conditioning; tone conditioning was not affected under either condition (cf., Young, Bohenek, & Fanselow, Neurobiology of Learning and Memory, 63, 174-180, 1995).
Anagnostaras
S G
SG
Department of Psychology, University of California, Los Angeles 90095-1563, USA.
Maren
S
S
Fanselow
M S
MS
D000818:Animals; D001245:Association Learning / Q000187:drug effects* / Q000502:physiology; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D003214:Conditioning, Classical / Q000187:drug effects* / Q000502:physiology; D004597:Electroshock; D005239:Fear / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D011939:Mental Recall / Q000187:drug effects* / Q000502:physiology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D051381:Rats; D012601:Scopolamine / Q000494:pharmacology*; D012931:Social Environment
D018727:Muscarinic Antagonists; D012601:Scopolamine