[Effects of Cu2+ on the neuromuscular junction transmission].
Experiments were carried out on the isolated rat phrenic nerve diaphragm preparations and chick biventer cervicis preparations. Cu2+ at cumulative concentrations inhibited muscle contractile response to indirect stimulation without affecting the conductivity of the nerve. The inhibiting action of Cu2+ on the muscle contractile response to indirect stimulation was stronger than that to direct stimulation. Cu2+ did not affect the Ach sensitivity of the chick biventer cervicis muscle. The effects of Cu2+ on neuromuscular transmission were antagonized by Ca2+ and L-cysteine. It is concluded that Cu2+ produces neuromuscular blockade by acting mainly on the presynaptic nerve terminals, binding with the -SH groups of the membrane and thus altering the transmembrane movement of Ca2+ and reducing the release of Ach from the nerve terminals.
Qi
Y F
YF
Department of Pharmacology, Faculty of Pharmacy, Xi'an Medical University.
Che
X P
XP
D000818:Animals; D002645:Chickens; D003300:Copper / Q000494:pharmacology*; D003545:Cysteine / Q000494:pharmacology; D004558:Electric Stimulation; D005260:Female; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000187:drug effects; D009469:Neuromuscular Junction / Q000502:physiology*; D010791:Phrenic Nerve / Q000187:drug effects; D051381:Rats; D009435:Synaptic Transmission / Q000187:drug effects*
D003300:Copper; D003545:Cysteine