Acetylcholine sensitivity in myotubes of nerve-muscle co-culture cultured with anti-muscle antibodies, alpha-bungarotoxin and D-tubocurarine.
The effects of alpha-bungarotoxin (alpha-BuTX), D-tubocurarine (D-TC) and antibodies against muscle extract on acetylcholine (ACh) sensitivity were investigated in developing mouse myotubes in a nerve-muscle co-culture. Antibodies clearly suppressed the ACh potential amplitude in adult mouse diaphragm muscle, but antibodies in muscle pre-treated with D-TC (1 microgram/ml) weakly suppressed it. The addition of D-TC to muscle extract dose-dependently inhibited the formation of the immunoprecipitation lines. The exposure of developing myotubes to antibodies for 10 days in culture suppressed both resting potential and ACh potential, whereas co-existence of alpha-BuTX (1 microgram/ml) or D-TC (0.1 mg/ml) with antibodies suppressed ACh potential but did not affect resting potential compared with antibodies alone. The ACh potentials in myotubes cultured with alpha-BuTX and D-TC alone were also suppressed. The appearance (day 8 in culture) of this suppressive effect by alpha-BuTX was faster than that (day 11 in culture) of D-TC. These different effects depending on the time in culture may account for the conformational change of developing ACh receptors to alpha-BuTX and D-TC.
Kimura
M
M
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Shikada
K
K
Nojima
H
H
Kimura
I
I
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D002038:Bungarotoxins / Q000494:pharmacology*; D002478:Cells, Cultured; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009132:Muscles / Q000166:cytology* / Q000187:drug effects / Q000276:immunology; D011950:Receptors, Cholinergic / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D014403:Tubocurarine / Q000494:pharmacology*
D002038:Bungarotoxins; D011950:Receptors, Cholinergic; D000109:Acetylcholine; D014403:Tubocurarine