The N-methyl-D-aspartate channel blocker ketamine does not attenuate, but enhances, locus coeruleus-induced potentiation in rat dentate gyrus.
Norepinephrine (NE)-induced potentiation of the perforant path-evoked potential is blocked by N-methyl-D-aspartate (NMDA) receptor antagonism in vitro. Does this occur in vivo? A saline and a ketamine micropipette monitored perforant path-evoked potentials in the dentate gyrus of urethane-anesthetized rats. Activation of locus coeruleus (LC) produced short- and long-term potentiation of the perforant path-evoked potential on both pipettes. Spike amplitude potentiation was enhanced on the ketamine pipette. In contrast high frequency-induced potentiation on the ketamine pipette was attenuated. LC-NE potentiation may not require NMDA channel activation in vivo.
Frizzell
L M
LM
Psychology Department, Memorial University of Newfoundland, St. John's, Canada.
Harley
C W
CW
D000818:Animals; D001931:Brain Mapping; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000502:physiology*; D007649:Ketamine / Q000494:pharmacology*; D008125:Locus Coeruleus / Q000502:physiology*; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology*; D013997:Time Factors
D007473:Ion Channels; D016194:Receptors, N-Methyl-D-Aspartate; D007649:Ketamine; D009638:Norepinephrine