Blockade of antidromic invasion of CA1 pyramidal cells during synaptic activation of NMDA receptors.
We have studied in situ the excitability state of the axon-soma membrane of CA1 pyramidal cells in the rat during synaptic activation of N-methyl-D-aspartate (NMDA) receptors. Repetitive activation (3-5 Hz) of Schaffer collaterals provoked a NMDA receptor-mediated component in the field excitatory postsynaptic potential (fEPSP) within 15 s. The generation of this component follows a characteristic self-limiting cycle, vanishing after 6-10 s. When alvear shocks were paired to the orthodromic volleys, the antidromic population spike (PS) was completely abolished only if the NMDA receptor-mediated fEPSP had occurred. This blockade of antidromic invasion lasted for 120-150 ms after each orthodromic shock. A reduction in the safety factor for axon-soma transmission is presumed during NMDA receptor synaptic activation.
Herreras
O
O
Dept. Investigación, Hospital Ramón y Cajal, Madrid, Spain.
Jing
J
J
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D010879:Piperazines / Q000494:pharmacology; D011712:Pyramidal Tracts / Q000187:drug effects / Q000502:physiology*; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology*; D013238:Stereotaxic Techniques; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
D010879:Piperazines; D011810:Quinoxalines; D016194:Receptors, N-Methyl-D-Aspartate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; C050592:3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid