TY - JOUR
T1 - Isoliquiritigenin, an active ingredient of Glycyrrhiza, elicits antinociceptive effects via inhibition of Nav channels
AU - Miyamura, Yuichi
AU - Hitomi, Suzuro
AU - Omiya, Yuji
AU - Ujihara, Izumi
AU - Kokabu, Shoichiro
AU - Morimoto, Yasuhiro
AU - Ono, Kentaro
N1 - Publisher Copyright:
© 2021, Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2021/5
Y1 - 2021/5
N2 - Glycyrrhiza extract has been used for the treatment of oral and gastric ulcers, but the analgesic mechanism remains unknown. In the present study, we investigated the effects of isoliquiritigenin, an active ingredient of Glycyrrhiza, on Nav channels in vitro and nociceptive behaviors in vivo. In an autopatch-clamp study, isoliquiritigenin inhibited the currents of Nav1.1, Nav1.3, Nav1.6, Nav1.7, and Nav1.8 in a channel expression system. In small- and medium-sized cultured trigeminal ganglion neurons, the compound suppressed Nav currents in many neurons (78%) and Kv currents in all neurons, dose-dependently. In current-clamp mode, isoliquiritigenin blocked action potential generation in many neurons (64%), but it conversely accelerated action potential generation in the remaining neurons. The opposing effects on action potentials were reproduced in a computational simulation of a modified Hodgkin-Huxley-based model, based on the electrophysiological data. In behavioral experiments, local treatment with isoliquiritigenin suppressed nociceptive behaviors in response to oral ulcer development or nociceptive TRP channel agonists in the oral mucosa and hind paw. These results suggest that isoliquiritigenin exerts an analgesic effect predominantly via inhibitory action on Nav channels on sensory nociceptive fibers. This pharmacological mechanism indicates that isoliquiritigenin is useful for pain relief and provides scientific evidence for Glycyrrhiza at the ingredient level.
AB - Glycyrrhiza extract has been used for the treatment of oral and gastric ulcers, but the analgesic mechanism remains unknown. In the present study, we investigated the effects of isoliquiritigenin, an active ingredient of Glycyrrhiza, on Nav channels in vitro and nociceptive behaviors in vivo. In an autopatch-clamp study, isoliquiritigenin inhibited the currents of Nav1.1, Nav1.3, Nav1.6, Nav1.7, and Nav1.8 in a channel expression system. In small- and medium-sized cultured trigeminal ganglion neurons, the compound suppressed Nav currents in many neurons (78%) and Kv currents in all neurons, dose-dependently. In current-clamp mode, isoliquiritigenin blocked action potential generation in many neurons (64%), but it conversely accelerated action potential generation in the remaining neurons. The opposing effects on action potentials were reproduced in a computational simulation of a modified Hodgkin-Huxley-based model, based on the electrophysiological data. In behavioral experiments, local treatment with isoliquiritigenin suppressed nociceptive behaviors in response to oral ulcer development or nociceptive TRP channel agonists in the oral mucosa and hind paw. These results suggest that isoliquiritigenin exerts an analgesic effect predominantly via inhibitory action on Nav channels on sensory nociceptive fibers. This pharmacological mechanism indicates that isoliquiritigenin is useful for pain relief and provides scientific evidence for Glycyrrhiza at the ingredient level.
KW - Isoliquiritigenin
KW - K channels
KW - Na channels
KW - NEURON simulation
KW - Nociception
UR - http://www.scopus.com/inward/record.url?scp=85099037388&partnerID=8YFLogxK
U2 - 10.1007/s00210-020-02030-w
DO - 10.1007/s00210-020-02030-w
M3 - Article
C2 - 33404688
AN - SCOPUS:85099037388
SN - 0028-1298
VL - 394
SP - 967
EP - 980
JO - Naunyn-Schmiedeberg's Archives of Pharmacology
JF - Naunyn-Schmiedeberg's Archives of Pharmacology
IS - 5
ER -