Acetylcholine-activated Cl- channel in the Chara tonoplast.
J Membr Biol
; 188(2): 107-13, 2002 Jul 15.
Article
in En
| MEDLINE
| ID: mdl-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.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Vacuoles
/
Acetylcholine
/
Chloride Channels
/
Eukaryota
Type of study:
Diagnostic_studies
Language:
En
Journal:
J Membr Biol
Year:
2002
Document type:
Article
Affiliation country:
United States