Direct activation of Ca2+ and voltage-gated potassium channels of large conductance by anandamide in endothelial cells does not support the presence of endothelial atypical cannabinoid receptor
| Autor: | Alexander I. Bondarenko, Fabrizio Montecucco, Olga Panasiuk, Karim J. Brandt, Iryna Okhai, François Mach |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
endothelial cannabinoid receptor Cannabinoid receptor Polyunsaturated Alkamides Arachidonic Acids 030204 cardiovascular system & hematology Article 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Human Umbilical Vein Endothelial Cells medicine anandamide Humans Large-Conductance Calcium-Activated Potassium Channels Paxilline Receptors Cannabinoid Pharmacology Membrane potential Chemistry BK(Ca) channels integrins Cell Membrane Voltage-gated potassium channel Anandamide Endocannabinoid system Endothelial stem cell Cholesterol 030104 developmental biology Biochemistry Potassium Channels Voltage-Gated Biophysics Calcium Ion Channel Gating Cannabidiol Endocannabinoids medicine.drug |
| Zdroj: | European Journal of Pharmacology. 805:14-24 |
| ISSN: | 0014-2999 |
| DOI: | 10.1016/j.ejphar.2017.03.038 |
| Popis: | Endocannabinoid anandamide induces endothelium-dependent relaxation commonly attributed to stimulation of the G-protein coupled endothelial anandamide receptor. The study addressed the receptor-independent effect of anandamide on large conductance Ca(2+)-dependent K(+) channels expressed in endothelial cell line EA.hy926. Under resting conditions, 10 μM anandamide did not significantly influence the resting membrane potential. In a Ca(2+)-free solution the cells were depolarized by ~10 mV. Further administration of 10 μM anandamide hyperpolarized the cells by ~8 mV. In voltage-clamp mode, anandamide elicited the outwardly rectifying whole-cell current sensitive to paxilline but insensitive to GDPβS, a G-protein inhibitor. Administration of 70 μM Mn(2+), an agent used to promote integrin clustering, reversibly stimulated whole-cell current, but failed to further facilitate the anandamide-stimulated current. In an inside-out configuration, anandamide (0.1–30 μM) facilitated single BK(Ca) channel activity in a concentration-dependent manner within a physiological Ca(2+) range and a wide range of voltages, mainly by reducing mean closed time. The effect is essentially eliminated following chelation of Ca(2+) from the cytosolic face and pre-exposure to cholesterol-reducing agent methyl-β-cyclodextrin. O-1918 (3 μM), a cannabidiol analog used as a selective antagonist of endothelial anandamide receptor, reduced BK(Ca) channel activity in inside-out patches. These results do not support the existence of endothelial cannabinoid receptor and indicate that anandamide acts as a direct BK(Ca) opener. The action does not require cell integrity or integrins and is caused by direct modification of BK(Ca) channel activity. |
| Databáze: | OpenAIRE |
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