Abscisic acid potentiates NMDA-gated currents in hippocampal neurones.
NMDA receptor functioning underlies the basic mechanism of synaptic plasticity of the central nervous system. The NMDA receptor is a subject for modulation by certain substances: facilitation of this receptor is thought to be crucial for the induction of plasticity phenomena. In the present investigation evidence for a potentiation of the NMDA-receptor by trans,trans-abscisic acid (postulated endogenous substance) is provided. Pre-exposure to trans,trans-abscisic acid induced a marked increase mainly of the fast component of NMDA-gated currents in isolated rat hippocampal neurones. The potentiating effect depended on an extracellular trans,trans-abscisic acid concentration with an EC50 value about 440 microM, Hill coefficient 2. Such a facilitatory effect developed rather slowly with a time constant of about 3 s. The results obtained imply the existence of a novel mechanism of NMDA receptor potentiation. The data presented indicate a possible neurophysiological significance of abscisin.
Pidoplichko
V I
VI
Department of Neurophysiology, Federal Institute for Neurobiology, Magdeburg, Germany.
Reymann
K G
KG
D000040:Abscisic Acid / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004553:Electric Conductivity; D005998:Glycine / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D015640:Ion Channel Gating; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects; D013997:Time Factors
D007473:Ion Channels; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; D000040:Abscisic Acid; D005998:Glycine