Effect of Mg2+ on non-quantal acetylcholine release at the mouse neuromuscular junction.
The effects of extracellular concentrations of Mg2+ on the non-quantal release of acetylcholine (ACh) from nerve terminals was studied by extra- and intracellular electrophysiological methods. Anticholinesterase-treated mouse diaphragms were used in vitro. In the presence of Ca2+, the non-quantal release was maximal in the absence of Mg2+ and was inhibited by 3 mmol/l Mg2+. The inhibitory effect of Mg2+ was antagonized by ouabain and was absent in Ca2+-free (EGTA) solutions. The non-quantal release of ACh was found to be more sensitive to inhibition by Mg2+ than the quantal one which was measured as the amplitude of miniature endplate currents.
Zemková
H
H
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Vyskocil
F
F
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D003964:Diaphragm / Q000187:drug effects; D004594:Electrophysiology; D005260:Female; D008274:Magnesium / Q000494:pharmacology*; D008564:Membrane Potentials; D051379:Mice; D009469:Neuromuscular Junction / Q000378:metabolism*
D008274:Magnesium; D000109:Acetylcholine