First selective potentiation of Ca2+ current through neuronal T-type calcium channels by the marine terpene fulvol acetate

Fulvol Acetate (Fig.1) is a new marine homosesquiterpene isolated from the soft coral Rhytisma fulvum. Electrophysiological investigations on short-term cultured pacemaker dorsal unpaired median (DUM) neurons isolated from the insect central nervous system highlighted that Fulvol Acetate increased selectively T-type calcium current (Fig.2). Fulvol Acetate used also increased T-type calcium current expressed by rat neurons from reticular thalamic and ventro-basal nuclei and dorsal root ganglion neurons. By contrast, the lack of effect of Fulvol Acetate on Xenopus oocytes that expressed only human cDNAs encoding Ca_V 3.1a, 3.2 or 3.3 α-subunits suggest an indirect effect of this compound on T-type current through the involvement of putative accessory proteins in such unusual activation.

Fig.1

Fig.2: LVA-Ca2+ current recording