Quisqualate activates a rapidly inactivating high conductance ionic channel in hippocampal neurons.
Glutamate activates a number of different receptor-channel complexes, each of which may contribute to generation of excitatory postsynaptic potentials in the mammalian central nervous system. The rapid application of the selective glutamate agonist, quisqualate, activates a large rapidly inactivating current (3 to 8 milliseconds), which is mediated by a neuronal ionic channel with high unitary conductance (35 picosiemens). The current through this channel shows pharmacologic characteristics similar to those observed for the fast excitatory postsynaptic current (EPSC); it reverses near 0 millivolts and shows no significant voltage dependence. The amplitude of the current through this channel is many times larger than that through the other non-NMDA (N-methyl-D-aspartate) channels. These results suggest that this high-conductance quisqualate-activated channel may mediate the fast EPSC in the mammalian central nervous system.
Tang
C M
CM
Department of Physiology, University of Pennsylvania, Philadelphia 19104.
Dichter
M
M
Morad
M
M
D000818:Animals; D004553:Electric Conductivity; D005971:Glutamates / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects; D010069:Oxadiazoles / Q000494:pharmacology*; D016318:Quisqualic Acid; D051381:Rats; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000502:physiology
D005971:Glutamates; D007473:Ion Channels; D010069:Oxadiazoles; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D016318:Quisqualic Acid