Differential effect of ketamine on the reference and working memory versions of the Morris water maze task.
The assumption that blockade of long-term potentiation by N-methyl-D-aspartate antagonists interferes with spatial memory was supported by experiments showing that 15 mg/kg ketamine impairs acquisition of navigation to a hidden platform but not to a visible platform. Higher doses were required to impair retrieval of overtrained place navigation. In a working memory version of the task, retrieval latencies were shorter than acquisition latencies with 4- to 15-min but not with 30- and 60-min delays. Latent learning was only effective with the 4-min delay. Ketamine prolonged the initial search of the hidden platform at 3 mg/kg and impaired latent learning but not active acquisition at 1.5-10 mg/kg. Comparison of behavioral and synaptic effects of ketamine suggests that long-term potentiation is a necessary condition, but not a sufficient condition, for acquisition of place navigation, because search strategy and latent place learning are impaired by ketamine doses not interfering with this synaptic phenomenon.
Wesierska
M
M
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Macias-Gonzalez
R
R
Bures
J
J
D000818:Animals; D001143:Arousal / Q000187:drug effects; D004193:Discrimination Learning / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects*; D009043:Motor Activity / Q000187:drug effects; D009949:Orientation / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000187:drug effects; D012153:Retention, Psychology / Q000187:drug effects*; D013550:Swimming; D009435:Synaptic Transmission / Q000187:drug effects
D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D007649:Ketamine