The effect of amantadine on nicotinic acetylcholine receptor (nAchR) in reconstituted membranes.
The antiviral drug amantadine is also a potent neuromuscular blocking agent. When the nicotinic receptor from a Torpedinidae species is reconstituted into soybean liposomes, the binding of ?-bungarotoxin is not altered although the carbamylcholine induced radioactive cation influx is blocked. By studying cation fluxes in amantadine preincubated membranes previously exposed to different concentrations of carbamylcholine for different periods of time, we have shown that the drug accelerates the conversion of the nicotinic acetylcholine receptor from a state of low affinity to a state of high affinity for carbamyalcholine, a phenomenon correlated with receptor desensitization. The drug did not induce such a shift by itself. The present data and those by Earnest et al. (Biochemistry22, 5523-5535, 1984) show that the nicotinic acetylcholine receptor reconstituted into liposomes is a good model for studying the effects of noncompetitive blockers of nicotinic acetylcholine receptor function.
Medrano
S
S
Instituto de Biologia Celular, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
Ochoa
E L
EL
McNamee
M G
MG