Post-training injections of catecholaminergic drugs do not modulate fear conditioning in rats and mice.
Studies employing classical fear conditioning (FC) and inhibitory avoidance (IA), two procedurally different aversive tasks, provide different insight into the neuronal mechanism(s) underlying fear learning. We examined whether immediate post-training injections of catecholaminergic drugs modulate memory consolidation in one-trial FC, as has been demonstrated in one-trial IA. Neither epinephrine (0.1, 0.3, 1.0 mg/kg intraperitoneally) nor amphetamine (1.0, 2.0 mg/kg) modulates FC to tone or context, as indicated by freezing in rats. Similarly, epinephrine (0.1, 1.0 mg/kg) and beta-adrenergic antagonists (sotalol and propranolol; 2 mg/kg) also failed to modulate FC in mice. These results indicate that FC is not susceptible to memory modulation by catecholaminergic drugs in the manner described in IA tasks.
Lee
H J
HJ
Department of Psychology, Yale University, 2 Hillhouse Avenue, New Haven, CT 06520-8205, USA.
Berger
S Y
SY
Stiedl
O
O
Spiess
J
J
Kim
J J
JJ
D000161:Acoustic Stimulation / Q000009:adverse effects; D000322:Adrenergic Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000661:Amphetamine / Q000494:pharmacology; D000679:Amygdala / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D002395:Catecholamines / Q000819:agonists* / Q000378:metabolism*; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology*; D004334:Drug Administration Schedule; D004558:Electric Stimulation / Q000009:adverse effects; D004837:Epinephrine / Q000494:pharmacology; D005239:Fear / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans
D000322:Adrenergic Agonists; D000319:Adrenergic beta-Antagonists; D002395:Catecholamines; D000661:Amphetamine; D004837:Epinephrine