[Effects of dantrolene and ryanodine on the evoked activity of neuromuscular synapses in mice].
Ryanodine was shown to potentiate in a frequency-dependent manner a late phase of initial facilitation increasing the EPP amplitude for 15%-40% in a fixed interval 140-400 ms after the first EPP in the discharge. Dantrolene prevented the ryanodine induced increase of the late phase of facilitation, decreased 2-fold the amplitude and quantum content of single EPPs, augmented initial depression, blocked facilitation in 50% of synapses. Only in presence of dantrolene, the ryanodine's ability to increase the EPPs quantum content and early phase of the EPP facilitation in rhythmically active synapses, was revealed.
Balezina
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OP
M. V. Lomonossov State University, 119899, Vorobievy Gory, Moscow, Russia.
Bukin
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AN
Lapteva
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D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D003620:Dantrolene / Q000494:pharmacology*; D066298:In Vitro Techniques; D008564:Membrane Potentials; D051379:Mice; D009045:Motor Endplate / Q000187:drug effects / Q000502:physiology; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D012433:Ryanodine / Q000494:pharmacology*; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects
D002121:Calcium Channel Blockers; D019837:Ryanodine Receptor Calcium Release Channel; D012433:Ryanodine; D003620:Dantrolene; D002118:Calcium