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Updated: Aug 24, 2026

Characterizing Modulators of Protease-Activated Receptors with a Calcium Mobilization Assay Using a Plate Reader
Published on: May 24, 2024
Marrubenol interacts with the phenylalkylamine binding site of the L-type calcium channel
Sanae El Bardai1, Marie-Christine Hamaide, Badiaa Lyoussi
1Laboratoire de Pharmacologie, Université Catholique de Louvain, UCL 5410, Avenue Hippocrate, 54, B-1200 Brussels, Belgium.
Abstract:
Marrubenol inhibits contraction of rat arteries by blocking L-type calcium (Ca(2+)) channels in smooth muscle cells, but its interaction with binding sites for calcium antagonists had never been investigated. Competition binding studies indicated that marrubenol was a weak inhibitor of 1,4-dihydropyridine binding in membranes isolated from rat intestinal smooth muscle but completely displaced specifically bound (-)-[(3)H]desmethoxyverapamil ([(3)H]D888) with an apparent K(i) value of 16 microM (95% confidence interval: 6.5-39.5 microM). As marrubenol inhibited the contraction evoked by KCl depolarization of intestinal smooth muscle half-maximally at a concentration of approximately 12 microM, interaction with the phenylalkylamine binding site seems to account for the inhibition of L-type Ca(2+) channels by marrubenol.
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