Referenced in: none

Automatically associated channels: Kir2.3

Title: Acetylcholine-activated Cl- channel in the Chara tonoplast.

Authors: X-Q Gong, M A Bisson

Journal, date & volume: J. Membr. Biol., 2002 Jul 15 , 188, 107-13

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/12172636

Abstract
Acetylcholine has long been suggested to play a role in controlling physiological processes in plants, but no mechanism has been shown for its action. We show here that a chloride channel in the tonoplast (vacuolar membrane) of Chara corallina responds to acetylcholine. The channel has a conductance of 45 pS. The effect of acetylcholine is enhanced by nicotine, with the open probability increasing from 0.05 in the presence of 4 mM acetylcholine to 0.3 in the presence of 4 mM acetylcholine + 6 mM nicotine. Some effects of acetylcholine were seen at concentrations as low as 20 microM, with a maximum effect between 1 and 10 mM. In the intact cell, acetylcholine prolongs the depolarized phase of the action potential. We propose that this acetylcholine-gated channel has evolved separately from the mammalian acetylcholine-gated channel, and suggest that this represents a third form of acetylcholine signal transduction, after the nicotinic and muscarinic pathways in animal systems.