TY - JOUR
T1 - Characterizing the effects of Eugenol on neuronal ionic currents and hyperexcitability
AU - Huang, Chin Wei
AU - Chow, Julie Chi
AU - Tsai, Jing Jane
AU - Wu, Sheng Nan
N1 - Funding Information:
Acknowledgements This research project was funded by the National Science Council (NSC-98-2320-B-006-027-MY3 and NSC-98-2314-B- 006-042-MY2) and the Program for Promoting Academic Excellence and Developing World Class Research Centers, Ministry of Education, Taiwan. This work was also supported in part by a grant from Buddhist Dalin Tzu-Chi General Hospital (DTCRD98-08), Chiayi County, Taiwan. The authors are grateful to Dr. Dong Chun Wu (Department of Neurology, University of British Columbia, Canada) for his critical comments on the manuscript.
PY - 2012/6
Y1 - 2012/6
N2 - Rationale: Eugenol (EUG, 4-allyl-2-methoxyphenol), the main component of essential oil extracted from cloves, has various uses in medicine because of its potential to modulate neuronal excitability. However, its effects on the ionic mechanisms remains incompletely understood. Objectives: We aimed to investigate EUG's effects on neuronal ionic currents and excitability, especially on voltage-gated ion currents, and to verify the effects on a hyperexcitability- temporal lobe seizure model. Methods: With the aid of patch-clamp technology, we first investigated the effects of EUG on ionic currents in NG108-15 neuronal cells differentiated with cyclic AMP. We then used modified Pinsky-Rinzel simulation modeling to evaluate its effects on spontaneous action potentials (APs). Finally, we investigated its effects on pilocarpine-induced seizures in rats. Results: EUG depressed the transient and late components of I Na in the neurons. It not only increased the degree of I Na inactivation, but specifically suppressed the non-inactivating I Na (I Na(NI)). Its inhibition of I Na(NI) was reversed by tefluthrin. In addition, EUG diminished L-type Ca 2+ current and delayed rectifier K + current only at higher concentrations. EUG's effects on APs frequency reduction was verified by the simulation modeling. In pilocarpine-induced seizures, the EUG-treated rats showed no shorter seizure latency but a lower seizure severity and mortality than the control rats. The EUG's effect on seizure severity was occluded by the I Na(NI) antagonist riluzole. Conclusion: The synergistic blocking effects of I Na and I Na(NI) contributes to the main mechanism through which EUG affects the firing of neuronal APs and modulate neuronal hyperexcitability such as pilocarpine-induced temporal lobe seizures.
AB - Rationale: Eugenol (EUG, 4-allyl-2-methoxyphenol), the main component of essential oil extracted from cloves, has various uses in medicine because of its potential to modulate neuronal excitability. However, its effects on the ionic mechanisms remains incompletely understood. Objectives: We aimed to investigate EUG's effects on neuronal ionic currents and excitability, especially on voltage-gated ion currents, and to verify the effects on a hyperexcitability- temporal lobe seizure model. Methods: With the aid of patch-clamp technology, we first investigated the effects of EUG on ionic currents in NG108-15 neuronal cells differentiated with cyclic AMP. We then used modified Pinsky-Rinzel simulation modeling to evaluate its effects on spontaneous action potentials (APs). Finally, we investigated its effects on pilocarpine-induced seizures in rats. Results: EUG depressed the transient and late components of I Na in the neurons. It not only increased the degree of I Na inactivation, but specifically suppressed the non-inactivating I Na (I Na(NI)). Its inhibition of I Na(NI) was reversed by tefluthrin. In addition, EUG diminished L-type Ca 2+ current and delayed rectifier K + current only at higher concentrations. EUG's effects on APs frequency reduction was verified by the simulation modeling. In pilocarpine-induced seizures, the EUG-treated rats showed no shorter seizure latency but a lower seizure severity and mortality than the control rats. The EUG's effect on seizure severity was occluded by the I Na(NI) antagonist riluzole. Conclusion: The synergistic blocking effects of I Na and I Na(NI) contributes to the main mechanism through which EUG affects the firing of neuronal APs and modulate neuronal hyperexcitability such as pilocarpine-induced temporal lobe seizures.
UR - https://www.scopus.com/pages/publications/84862688950
UR - https://www.scopus.com/pages/publications/84862688950#tab=citedBy
U2 - 10.1007/s00213-011-2603-y
DO - 10.1007/s00213-011-2603-y
M3 - Article
C2 - 22160139
AN - SCOPUS:84862688950
SN - 0033-3158
VL - 221
SP - 575
EP - 587
JO - Psychopharmacology
JF - Psychopharmacology
IS - 4
ER -