Epileptiform activity induced by magnesium-free solution in slices of rat amygdala: antagonism by N-methyl-D-aspartate receptor antagonists.
The effects of the N-methyl-D-aspartate (NMDA) receptor antagonists, D-2-amino-5-phosphonovalerate (D-APV) and phencyclidine (PCP), were studied in vitro on epileptiform activity induced in magnesium-free solution in neurons of the basolateral amygdala of the rat, using intracellular recording techniques. Twenty to 30 min after switching to magnesium-free medium, spontaneous interictal-like events were observed in 33 out of 37 amygdala slices. The spontaneous interictal-like events consisted of an initial burst followed by a number of afterdischarges. Superfusion with D-APV, a competitive NMDA receptor antagonist, reversibly reduced the duration of the events was also reduced. The IC50, estimated from the graph of the concentration-response relationship, was approximately 10 microM which is close to the IC50 for the binding of D-AVP to the NMDA receptor in other regions of the brain. The effect of phencyclidine, a noncompetitive NMDA receptor antagonist, was similar to that of D-APV. These results suggest that activation of NMDA receptors plays an intrinsic role in the induction or propagation of epileptiform activity seen in magnesium-free solution in the neurons of the amygdala.
D015763:2-Amino-5-phosphonovalerate; D000679:Amygdala / Q000187:drug effects* / Q000503:physiopathology; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D004827:Epilepsy / Q000139:chemically induced* / Q000503:physiopathology; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D008839:Microelectrodes; D009474:Neurons / Q000187:drug effects; D010622:Phencyclidine / Q000494:pharmacology*; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000187:drug effects*; D014633:Valine / Q000031:analogs & derivatives* / Q000494:pharmacology
D000927:Anticonvulsants; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D015763:2-Amino-5-phosphonovalerate; D014633:Valine; D008274:Magnesium; D010622:Phencyclidine