pre·​syn·​ap·​tic ˌprē-sə-ˈnap-tik How to pronounce presynaptic (audio)
: of, occurring in, or being a neuron by which a nerve impulse is conveyed to a synapse
a presynaptic membrane
a presynaptic neuron
presynaptically adverb

Examples of presynaptic in a Sentence

Recent Examples on the Web In fact, the preceding neurons that send incoming signals are referred to as presynaptic neurons - again, ‘pre’ meaning ‘before the synapse’ - and the neuron that is receiving all the signals is the postsynaptic neuron - ‘post’ implying after the synapse. Gabriel A. Silva, Forbes, 19 Apr. 2021 The endocannabinoid payload then travels backward to the presynaptic neuron — the neuron that originally sent the signal — and exerts a dampening effect, limiting the amount of neurotransmitter chemicals those cells can release. Ben Thomas, Discover Magazine, 19 Oct. 2015 For example, sponge neuroid cells not only express some of the presynaptic machinery of neurons, but also express immune genes. Quanta Magazine, 4 Nov. 2021 The findings from this new study seem to bear on that mystery because the researchers found presynaptic gene sets expressed in neuroid cells and postsynaptic genes expressed in choanocytes. Quanta Magazine, 4 Nov. 2021 It had been observed that vesicles containing neurotransmitters routinely hover in clusters near the presynaptic membrane until they are needed. Quanta Magazine, 26 Nov. 2018

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'presynaptic.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1937, in the meaning defined above

Time Traveler
The first known use of presynaptic was in 1937

Dictionary Entries Near presynaptic

Cite this Entry

“Presynaptic.” Dictionary, Merriam-Webster, Accessed 21 Jul. 2024.

Medical Definition


pre·​syn·​ap·​tic -sə-ˈnap-tik How to pronounce presynaptic (audio)
: relating to, occurring in, or being part of a neuron by which a nerve impulse is conveyed to a synapse
presynaptic terminals
presynaptic inhibition
a presynaptic membrane
presynaptically adverb
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