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 +/- 35 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 Ca(2+)-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 Ca(2+)-induced-Ca(2+)-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.
Chu
T C
TC
Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA. TC@link.msm.edu
Burch
J L
JL
de Paula Brotto
M A
MA
Creazzo
T L
TL
Han
J
J
Han
G Y
GY
Potter
D E
DE
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002924:Ciliary Body / Q000166:cytology / Q000187:drug effects*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004220:Disulfides; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects; D016257:Fura-2 / Q000737:chemistry; D000960:Hypolipidemic Agents / Q000494:pharmacology*; D008856:Microscopy, Fluorescence; D011817:Rabbits; D013441:Sulfinic Acids / Q000494:pharmacology*
D000975:Antioxidants; D004220:Disulfides; D000960:Hypolipidemic Agents; D013441:Sulfinic Acids; C006452:allicin; D002118:Calcium; D016257:Fura-2