Increase in the indole alkaloid production and its excretion into the culture medium by calcium antagonists in Catharanthus roseus hairy roots.

Treatment of Catharanthus roseus hairy roots with antagonists, like verapamil and CdCl2, that block the Ca2+ flux across the plasma membrane enhanced the total alkaloid content by 25% and their secretion 10 times. The specific Ca2+ chelator, EGTA, stimulated 90% of the total alkaloid secretion. Treatment with inhibitors of intracellular Ca2- movement, like TMB-8 and trapsigargin, enhanced the total alkaloid content by 74% and their secretion into the culture media by 4- to 6-fold. The results suggest that an inhibition of external and internal Ca2+ fluxes induces an increase in the indole alkaloid accumulation and secretion in C. roseus hairy roots.