Nonselective block by La3+ of Arabidopsis ion channels involved in signal transduction

J Membr Biol. 1998 Mar 1;162(1):81-90. doi: 10.1007/s002329900344.


Lanthanide ions such as La3+ are frequently used as blockers to test the involvement of calcium channels in plant and animal signal transduction pathways. For example, the large rise in cytoplasmic Ca2+ concentration triggered by cold shock in Arabidopsis seedlings is effectively blocked by 10 mM La3+ and we show here that the simultaneous large membrane depolarization is similarly blocked. However, a pharmacological tool is only as useful as it is selective and the specificity of La3+ for calcium channels was brought into question by our finding that it also blocked a blue light (BL)-induced depolarization that results from anion channel activation and believed not to involve calcium channels. This unexpected inhibitory effect of La3+ on the BL-induced depolarization is explained by our finding that 10 mM La3+ directly and completely blocked the BL-activated anion channel when applied to excised patches. We have investigated the ability of La3+ to block noncalcium channels in Arabidopsis. In addition to the BL-activated anion channel, 10 mM La3+ blocked a cation channel and a stretch-activated channel in patches of plasma membrane excised from hypocotyl cells. In root cells, 10 mM La3+ inhibited the activity of an outward-rectifying potassium channel at the whole cell and single-channel level by 47% and 58%, respectively. We conclude that La3+ is a nonspecific blocker of multiple ionic conductances in Arabidopsis and may disrupt signal transduction processes independently of any effect on Ca2+ channels.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arabidopsis / drug effects
  • Calcium / metabolism
  • Cell Membrane / physiology
  • Cold Temperature
  • Ion Channels / drug effects*
  • Ion Channels / physiology
  • Lanthanum / pharmacology*
  • Light
  • Signal Transduction*


  • Ion Channels
  • Lanthanum
  • Calcium