Soluble epoxide hydrolase inhibitor enhances synaptic neurotransmission and plasticity in mouse prefrontal cortex.
BACKGROUND
The soluble epoxide hydrolase (sEH) is an important enzyme chiefly involved in the metabolism of fatty acid signaling molecules termed epoxyeicosatrienoic acids (EETs). sEH inhibition (sEHI) has proven to be protective against experimental cerebral ischemia, and it is emerging as a therapeutic target for prevention and treatment of ischemic stroke. However, the role of sEH on synaptic function in the central nervous system is still largely unknown. This study aimed to test whether sEH C-terminal epoxide hydrolase inhibitor, 12-(3-adamantan-1-yl-ureido) dodecanoic acid (AUDA) affects basal synaptic transmission and synaptic plasticity in the prefrontal cortex area (PFC). Whole cell and extracellular recording examined the miniature excitatory postsynaptic currents (mEPSCs) and field excitatory postsynaptic potentials (fEPSPs); Western Blotting determined the protein levels of glutamate receptors and ERK phosphorylation in acute medial PFC slices.


RESULTS
Application of the sEH C-terminal epoxide hydrolase inhibitor, AUDA significantly increased the amplitude of mEPSCs and fEPSPs in prefrontal cortex neurons, while additionally enhancing long term potentiation (LTP). Western Blotting demonstrated that AUDA treatment increased the expression of the N-methyl-D-aspartate receptor (NMDA) subunits NR1, NR2A, NR2B; the α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluR1, GluR2, and ERK phosphorylation.


CONCLUSIONS
Inhibition of sEH induced an enhancement of PFC neuronal synaptic neurotransmission. This enhancement of synaptic neurotransmission is associated with an enhanced postsynaptic glutamatergic receptor and postsynaptic glutamatergic receptor mediated synaptic LTP. LTP is enhanced via ERK phosphorylation resulting from the delivery of glutamate receptors into the PFC by post-synapse by treatment with AUDA. These findings provide a possible link between synaptic function and memory processes.
Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, 11221, Taiwan.
Han-Fang
HF
Wu
Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, 11221, Taiwan.
Hsin-Ju
HJ
Yen
Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, 11031, Taiwan.|Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, 11031, Taiwan.
Chi-Chen
CC
Huang
Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, 11031, Taiwan.|Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, 11031, Taiwan.
Yi-Chao
YC
Lee
Department of Anesthesiology, Chi-Mei Medical Center, Tainan, Taiwan.
Su-Zhen
SZ
Wu
Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, 11221, Taiwan.|Brain Research Center, National Yang-Ming University, Taipei, 11221, Taiwan.
Tzong-Shyuan
TS
Lee
Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, 11221, Taiwan. hclin7@ym.edu.tw.|Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, 11031, Taiwan. hclin7@ym.edu.tw.|Brain Research Center, National Yang-Ming University, Taipei, 11221, Taiwan. hclin7@ym.edu.tw.
Hui-Ching
HC
Lin
D000218:Adamantane / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D004851:Epoxide Hydrolases / Q000037:antagonists & inhibitors*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D007850:Lauric Acids / Q000494:pharmacology*; D051379:Mice; D009473:Neuronal Plasticity / Q000187:drug effects*; D017397:Prefrontal Cortex / Q000378:metabolism*; D018091:Receptors, AMPA / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects*
D000218:Adamantane; D004851:Epoxide Hydrolases; D048049:Extracellular Signal-Regulated MAP Kinases; D007850:Lauric Acids; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; C504897:12-(3-adamantan-1-ylureido)dodecanoic acid; C104722:glutamate receptor ionotropic, AMPA 2