Sentences with phrase «ion concentration directly»

When elevating calcium ion concentration directly at the presynaptic terminal with the use of caged calcium, cleavage of SNAP - 25 by botulinum toxin A (BoNT / A) produced a strong reduction in the calcium sensitivity for release, whereas cleavage of syntaxin using BoNT / C1 and synaptobrevin using tetanus toxin (TeNT) produced an all - or - nothing block without changing the kinetics of remaining vesicles.