The effect of ethanol, vasopressin and bradykinin on cytosolic Ca2+ concentration ([Ca2+]i) levels was studied upon in the perfused livers obtained from Wistar rats. [Ca2+]i was measured using a fluorescence Ca2+ Indo-1 probe. The ED50 was found to be 500 mM for ethanol and 10 nM for vasopressin. Ethanol had a long lasting effect in elevating [Ca2+]i levels in contrast to the transient effect of vasopressin. Vasopressin failed to increase [Ca2+]i levels when applied after ethanol and vice versa. Depletion of intracellular Ca2+ stores by ryanodine and bradykinin (10 nM) had no effect on [Ca2+]i levels. In contrast, ethanol (500 mM) and vasopressin (10 nM) caused an increase in the calcium concentration level [Ca2+]i by 49% and 44% respectively, as compared to the control group. Perfusion with calcium free solution following ryanodine treatment resulted in an ineffectiveness of all three calcium agonists. This data suggest that ethanol and vasopressin increase the Ca2+ flux through the cell membrane and that they seem to influence the same intracellular calcium pools.

Keywords: Fluorometry, Ryanodine, Inositol, Rat