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Docosahexaenoic acid inhibits synaptic transmission and epileptiform activity in the rat hippocampus
Author(s) -
Young Chainllie,
Gean PoWu,
Chiou LihChu,
Shen YuZen
Publication year - 2000
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/1098-2396(200008)37:2<90::aid-syn2>3.0.co;2-z
Subject(s) - excitatory postsynaptic potential , bicuculline , schaffer collateral , bursting , neuroscience , neurotransmission , chemistry , hippocampal formation , depolarization , hippocampus , slice preparation , interneuron , inhibitory postsynaptic potential , synaptic plasticity , stimulation , electrophysiology , biophysics , biology , gabaa receptor , biochemistry , receptor
Docosahexaenoic acid (DHA) has been suggested to be required for neuronal development and synaptic plasticity. However, in view of the fact that DHA facilitates NMDA responses and blocks K + channels, it might predispose the neurons to epileptiform bursting. By using extracellular recording of population spikes in the CA1 region of rat hippocampal slices, we tested this possibility by examining the effect of DHA on the epileptiform activity induced by bicuculline or in Mg 2+ ‐free medium. When stimuli were delivered to the Schaffer collateral/commissural pathway every 20 or 30 sec, DHA had no significant effect on the epileptiform activity. However, when the frequency of stimulation was increased to 0.2 Hz, DHA attenuated the amplitude of the bursting activity induced by bicuculline to 57.5 ± 10.8% and those induced by Mg 2+ ‐free ACSF to 65.8 ± 13.9% of control. DHA reduced the slope of field excitatory postsynaptic potential (fEPSP) to 77.1 ± 7.4% of baseline, without significant effect on the ratio of paired‐pulse facilitation (PPF). By intracellular recording of neurons in the stratum pyramidale of rat hippocampal slices, we found that DHA markedly inhibited the repetitive firing of action potentials elicited by depolarizing current pulses but did not affect the initial action potential. Thus, DHA may attenuate epileptic activity mainly through the frequency‐dependent blockade of Na + channels. Synapse 37:90–94, 2000. © 2000 Wiley‐Liss, Inc.