Suppression of spontaneous calcium spikes and contraction in isolated portal veins of mice by gingerols and chemically related compounds.

The suppression of spontaneous Ca2+ spikes and isometric contractions by gingerols and their chemically related compounds was examined using the single sucrose gap method. Most of the congeners tested suppressed spontaneous contraction, which was not necessarily accompanied by the suppression of Ca2+ spikes. The most potent analogues for Ca2+ spike suppression were (+/-)-[6]-gingerol (0.3 mM) and (+/-)-yakuchinone-A (0.3 mM). These compounds also strongly inhibited spontaneous contraction. In contrast, (+/-)-[8]-gingerol (0.3 mM) inhibited the contraction without changing the Ca2+ spikes. These results suggest that the inhibition of spontaneous contraction induced by (+/-)-[6]-gingerol, but not by (+/-)-[8]-gingerol, is due to the Ca2+ spike suppression.