Ketamine suppresses synchronized discharges in the disinhibited amygdala slice.
The effect of ketamine on the paroxysmal depolarizing shift (PDS) induced by bicuculline was studied in rat amygdala slices using intracellular recording techniques. Stimulation of the ventral endopyriform nucleus evoked an excitatory postsynaptic potential (EPSP). After exposure to bicuculline (20 microM), the same stimulus intensity evoked burst firing. Superfusion of ketamine reversibly reduced the duration of PDS. Pretreatment of amygdala slices with DL-2-amino-5-phosphonovaleate (DL-APV, 50 microM) occluded the effect of ketamine suggesting that ketamine shortened the burst duration via its blocking action on the NMDA receptors. In all neurons tested, a large depolarizing shift remained in the presence of ketamine. The ketamine-resistant component was blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 8 microM) indicating its mediation by the non-NMDA receptors.
Department of Pharmacology, College of Medicine, National Cheng-Kung University, Tainan City, Taiwan, R.O.C.
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PW
Gean
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Chang
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000679:Amygdala / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D066298:In Vitro Techniques; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D008839:Microelectrodes; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013569:Synapses / Q000187:drug effects / Q000502:physiology
D007649:Ketamine; D015763:2-Amino-5-phosphonovalerate; D001640:Bicuculline