title: Adenosine A1 receptor activation selectively impairs the acquisition of contextual fear conditioning in rats.
abstract: Three experiments were conducted to examine the importance of adenosine A1 receptors for the acquisition and expression of hippocampal-dependent and hippocampal-independent forms of conditioned fear. In Experiment 1, the selective adenosine A1 receptor agonist, N6-cyclopentyladenosine (CPA), or saline was administered intraperitoneally to male rats 30 min prior to Pavlovian fear conditioning, which consisted of 7 tone-shock pairings. Adenosine A1 receptor activation dose-dependently and selectively disrupted the acquisition of contextual fear conditioning while sparing tone-shock associations. Experiments 2 and 3 demonstrated that CPA's selective disruption of contextual learning could not be attributed to context being weaker than tone conditioning or to state-dependent learning. Adenosine A1 receptor activation also impaired the expression of both context- and tone-elicited fear. These results suggest that endogenous adenosine modulates the acquisition and expression of emotional (fear) memories by acting on A1 receptors in brain regions underlying fear conditioning.
authors.affiliation: Psychology Program, School of Sciences, Lynchburg College, Virginia 24501-3199, USA. corodimas@lynchburg.edu
authors.forename: K P
authors.initials: KP
authors.lastname: Corodimas
authors.forename: H
authors.initials: H
authors.lastname: Tomita
mesh_terms: D000818:Animals; D001362:Avoidance Learning; D005239:Fear; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D008568:Memory; D051381:Rats; D017207:Rats, Sprague-Dawley; D018047:Receptors, Purinergic P1 / Q000502:physiology*
chemical_list: D018047:Receptors, Purinergic P1