The effect of the NMDA receptor antagonist MK-801 on the acquisition and extinction of learned fear in the developing rat.
Recent findings reveal qualitative developmental differences in extinction of learned fear. The present study explored potential developmental differences in the role of NMDA in acquisition and extinction. Rats were injected with MK-801 prior to fear conditioning or extinction training. Acquisition was found to be NMDA dependent in both age groups, whereas extinction was found to be NMDA dependent in 23-day-old rats, but NMDA independent in 16-day-old rats. These results illustrate another fundamental developmental difference in extinction as well as a dissociation in the role of NMDA in the acquisition and extinction of fear early in development.
Langton
Julia M
JM
School of Psychology, The University of New South Wales, Sydney 2052, Australia. jlangton@psy.unsw.edu.au
Kim
Jee Hyun
JH
Nicholas
Jennifer
J
Richardson
Rick
R
D000367:Age Factors; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005108:Extinction, Psychological / Q000187:drug effects*; D005239:Fear / Q000187:drug effects* / Q000502:physiology; D046352:Freezing Reaction, Cataleptic / Q000187:drug effects / Q000502:physiology; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology*; D014633:Valine / Q000031:analogs & derivatives
D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate; C056639:2-amino-5-phosphopentanoic acid; D014633:Valine