Effects of philanthotoxin-343 on CA1 pyramidal neurons of rat hippocampus in vitro.
A synthetic analog of philanthotoxin-433, philanthotoxin-343 (PhTX-343), was tested in hippocampal pyramidal neurons in vitro. PhTX-343 (2 microM) did not significantly change synaptic transmission mediated by AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)/kainate receptors in the CA1 region of hippocampus. However, PhTX-343 significantly suppressed both the synaptic N-methyl-D-aspartate receptor-induced current (NMDA) obtained in the presence of CNQX(6-cyano-7-nitroquinoxaline-2,3-dione)/picrotoxin (10 microM) and the directly evoked NMDA receptor-induced current to pressure ejection of NMDA in the presence of tetrodotoxin (0.5 microM). A short transient facilitation of both types of NMDA response was seen immediately after the beginning of PhTX-343 application. Our results suggest that at high concentration (2 microM) PhTX-343 inhibits the NMDA-gated current, while the early facilitation occurred during an initial low concentration of the compound. Both facilitative and depressive actions of PhTX-343 are localized at the postsynaptic membrane.
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000818:Animals; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects*; D007051:Ibotenic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D010636:Phenols / Q000494:pharmacology*; D011073:Polyamines / Q000494:pharmacology*; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA; D017470:Receptors, Glutamate / Q000187:drug effects / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects*; D013779:Tetrodotoxin / Q000494:pharmacology; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
D010636:Phenols; D011073:Polyamines; D011810:Quinoxalines; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C074003:philanthotoxin 343; D007051:Ibotenic Acid; D013779:Tetrodotoxin; D016202:N-Methylaspartate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid