Abstract
Effects of rare earth elements (atomic numbers, 39, 57-60, 62-71; Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) and Al added as chloride salts, on Ca2+ influx induced by two inducers of Ca2+ influx via distinct calcium channels, namely hypoosmotic shock and salicylic acid, were examined in a suspension-cultured transgenic cell line of BY-2 tobacco (Nicotiana tabacum) cells expressing a Ca2+-sensitive luminescent protein, aequorin. Most metals showed inhibitory effect against Ca2+ influx. Especially Nd, Sm, Eu, Gd and Tb showed the most robust inhibitory action. Interestingly, selective inhibition of the salicylate-induced Ca2+ influx by Pr at a low dose (ca. 0.1 mM) and by Al at high doses (5 - 10 mM) was observed. Lastly, the effects of above putative inhibitors were examined in the cell lines with modified TPC1 type channel expression.
