Zinc antagonizes the effect of botulinum type A toxin at the mouse neuromuscular junction.
Zn2+ (10-100 microM) elevated the frequency of miniature end-plate potentials (MEPPs) in the mouse diaphragm. The effect did not depend on external Ca2+. Botulinum type A toxin (BTXA, 50 ng/ml) abolished MEPPs almost completely within 30 min. Zn2+ (100 microM) restored MEPPs and increased their frequency after they had been abolished by BTXA in Ca2+ -free solutions. The antagonistic effect of Zn2+ in the Ca2+ -free solution was reduced by exposing the diaphragm to the toxin in the Ca2+ -free solutions containing high K+. Thus, the action of BTXA is probably enhanced by depolarization of the motor nerve terminals.
Nishimura
M
M
Department of Veterinary Science, College of Agriculture, University of Osaka Prefecture, Japan.
Kozaki
S
S
Sakaguchi
G
G
D000818:Animals; D001905:Botulinum Toxins / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D003964:Diaphragm / Q000502:physiology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology*; D011189:Potassium Chloride / Q000494:pharmacology; D015032:Zinc / Q000494:pharmacology*
D011189:Potassium Chloride; D001905:Botulinum Toxins; D015032:Zinc; D002118:Calcium