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The decrease in the presynaptic calcium current is a major cause of short-term depression at a calyx-type synapse.

Jianhua Xu·Ling-Gang Wu
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Abstract

Repetitive nerve firings cause short-term depression (STD) of release at many synapses. Its underlying mechanism is largely attributed to depletion of a readily releasable vesicle pool (RRP) and a decreased probability of releasing a readily releasable vesicle during an action potential. Which of these two mechanisms is dominant and the mechanism that decreases the release probability remain debated. Here, we report that a decreased release probability is caused by a calcium-induced inhibition of presynaptic calcium channels, particularly P/Q-type channels at the calyx of Held in rat brainstem. This mechanism was the dominant cause of STD in a wide range of stimulation conditions, such as during 2 to 20 action potential-equivalent stimuli (AP-e) at 0.2-30 Hz and after 2 to 20 AP-e at 0.2-100 Hz. Only during > or = 100 Hz AP-e was depletion the dominant mechanism.

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Action PotentialsAnimalsAnimals, NewbornBariumBrain StemCREB-Binding ProteinCalciumCalcium ChannelsChelating AgentsDose-Response Relationship, RadiationEgtazic AcidElectric CapacitanceElectric StimulationEnzyme InhibitorsImidazolesIn Vitro TechniquesModels, BiologicalNeural InhibitionNuclear ProteinsPatch-Clamp TechniquesPeptidesPresynaptic TerminalsRatsRats, WistarSynapsesTime FactorsTrans-ActivatorsComparative StudyJournal ArticleResearch Support, N.I.H., IntramuralResearch Support, U.S. Gov't, P.H.S.

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Jianhua Xu, Ling-Gang Wu. 2005-05-19. The decrease in the presynaptic calcium current is a major cause of short-term depression at a calyx-type synapse.. https://doi.org/10.1016/j.neuron.2005.03.024

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