Triphenylmethylphosphonium is an ion channel ligand of the nicotinic acetylcholine receptor.
AUTOR(ES)
Lauffer, L
RESUMO
The lipophilic cation triphenylmethylphosphonium (Ph3MeP+), which is widely used as a sensor for membrane potential with cells, organelles, and membrane vesicles, is shown also to accumulate in membranes rich in nicotinic acetylcholine receptor in a voltage-independent way. Evidence is presented that Ph3MeP+ in this system is bound to a cation-binding site of the ion channel that is part of the acetylcholine receptor complex. Binding is stimulated by cholinergic effectors (Kd = 13 microM in the absence of carbamoylcholine; Kd = 1.5 microM in the presence of 10 microM carbamoylcholine), and this stimulation is blocked by alpha-bungarotoxin. Ph3MeP+ blocks efflux of 22Na from receptor-rich microsacs and appears to compete with the channel ligand phencyclidine for a common binding site. In contrast to the binding of other proven channel ligands, Ph3MeP+-binding is not affected by desensitization.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=346203Documentos Relacionados
- Amphipathic analysis and possible formation of the ion channel in an acetylcholine receptor.
- Conformation of acetylcholine bound to the nicotinic acetylcholine receptor.
- Perhydrohistrionicotoxin: a potential ligand for the ion conductance modulator of the acetylcholine receptor.
- An inhalational anesthetic binding domain in the nicotinic acetylcholine receptor.
- Photolabeling reveals the proximity of the alpha-neurotoxin binding site to the M2 helix of the ion channel in the nicotinic acetylcholine receptor.