Elevation of intracellular Ca²⁺ concentration in rabbit nonpigmented ciliary epithelial cells by allicin

A previous study has shown that allicin produces changes in aqueous humor dynamics, and this study was conducted to examine possible cellular mechanisms. In rabbit nonpigmented ciliary epithelial cells, basal levels of [Ca²⁺](i) were determined to be 164 ± 34 nM. Allicin, a sulfhydryl-reactive agent, induced Ca²⁺ transients at 0.01 mM and at 0.2 mM, the Ca²⁺ transient peaked at 732 ± 33 nM. Allicin-induced Ca²⁺ transients were prevented by pretreatment with dithiothreitol which did not affect the basal Ca²⁺ levels. Allicin had only a slight, insignificant, effect on L-type Ca²⁺ currents, and allicin-induced Ca²⁺ transients were also present under extracellular Ca²⁺-free conditions. These data suggest that intracellular Ca²⁺ stores are the most probable source of allicin's effect. Pretreatment of cells with ryanodine, an inhibitor of Ca²⁺-induced-Ca²⁺-release, inhibited allicin-induced Ca²⁺ transients, but the basal Ca²⁺ levels were unaffected by ryanodine. Thus, allicin-induced Ca²⁺ transients are most likely mediated through ryanodine-sensitive intracellular Ca²⁺ stores. Copyright (C) 1996 Elsevier Science Inc.