Post-synaptic N-methyl-d-aspartate signalling in hippocampal neurons of rat: spillover increases the impact of each spike in a short burst discharge.
High-frequency burst discharges in hippocampus typically consist of less than ten spikes fired at frequencies too high to be followed by a post-synaptic neuron. How significant are these numbers for synaptic signalling? We have measured the N-methyl-d-aspartate (NMDA) component of the excitatory post-synaptic current (EPSC(NMDA)) in hippocampal CA1 neurons of rat after burst discharge of variable duration. The synaptic facilitation is accompanied by a slow-down of the EPSC(NMDA) which develops on a spike-to-spike basis. Consequently the charge transferred by the after-burst EPSC(NMDA) is increased with each spike. The phenomenon is most probably due to the spillover-mediated recruitment of extrasynaptic NMDA receptors. In terms of post-synaptic signalling it dramatically increases the impact of each spike in a short burst discharge.
Grebenyuk
Sergei E
SE
Bogomoletz Institute of Physiology, 4, Bogomoletz St., 01024 Kiev, Ukraine.
Lozovaya
Natasha A
NA
Tsintsadze
Timur S
TS
Krishtal
Oleg A
OA
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D018698:Glutamic Acid / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013570:Synaptic Membranes / Q000187:drug effects / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid