Nicotinic acetylcholine receptor is involved in acetylcholine regulating stomatal movement

In animal cells, actions of acetylcholine depend on its binding to specific receptors. Activation of nicotinic acetylcholine receptor can affect the membrane permeability to ions directly. As concerned about acetylcholine regulating stomatal movement, nicotinic acetylcholine receptor may also be involved. Experiments with nicotinic acetylcholine receptor antagonist (D\|tubocurarine) and agonist (nicotine) showed that nicotinic acetylcholine receptor was involved in acetylcholine inducing stomatal opening. In addition, these effects of D\|tubocurarine and nicotine on stomatal movement can only be found in medium containing K\++ while no effects can be found in medium containing Ca 2+ . The result by Western blotting showed that at least α\| and β\|subunits of nicotinic receptor existed in microsomes of guard cell protoplasts. It was found that the distribution of nicotinic acetylcholine receptor was mainly on the surface of protoplasts as shown by FITC labelled α\|bungarotoxin. The results above show that nicotinic acetylcholine receptor exists in guard cells and mediates acetylchlone to induce stomatal opening.