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Updated: Jul 12, 2026

In-Vivo Calcium Imaging of Sensory Neurons in the Rat Trigeminal Ganglion
Published on: February 9, 2024
Eugenol inhibits K+ currents in trigeminal ganglion neurons
1Department of Physiology and Program in Molecular and Cellular Neuroscience, School of Dentistry and Dental Research Institute, Seoul National University, 28-2 Yeongeon-Dong Chongno-Ku, Seoul, Korea.
Unlabelled:
Eugenol, a natural capsaicin congener, is widely used in dentistry. Eugenol inhibits voltage-activated Na(+) and Ca(2+) channels in a transient receptor potential vanilloid 1 (TRPV1)-independent manner. We hypothesized that eugenol also inhibits voltage-gated K(+) currents, and investigated this in rat trigeminal ganglion neurons and in a heterologous system using whole-cell patch clamping. Eugenol inhibited voltage-gated K(+) currents, and the inhibitory effects of eugenol were observed in both capsaicin-sensitive and capsaicin-insensitive neurons. Pre-treatment with capsazepine, a well-known antagonist of TRPV1, failed to block the inhibitory effects of eugenol on K(+) currents, suggesting no involvement of TRPV1. Eugenol inhibited human Kv1.5 currents stably expressed in Ltk(-) cells, where TRPV1 is not endogenously expressed. We conclude that eugenol inhibits voltage-gated K(+) currents in a TRPV1-independent manner. The inhibition of voltage-gated K(+) currents is likely to contribute to the irritable action of eugenol.
Abbreviations:
human Kv1.5 channel, hKv1.5; transient receptor potential vanilloid 1, TRPV1.
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