presynaptic
adjective
pre·syn·ap·tic
ˌprē-sə-ˈnap-tik 
: of, occurring in, or being a neuron by which a nerve impulse is conveyed to a synapse
a presynaptic membrane
a presynaptic neuron
Examples of presynaptic in a Sentence
Recent Examples on the Web
Among the most important components are powerful presynaptic neurotoxins.
—
Scott Travers,
Forbes.com,
12 June 2026
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 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
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Scott Travers,
Forbes.com,
12 June 2026
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 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
Cite this Entry
“Presynaptic.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/presynaptic. Accessed 5 Jul. 2026.
Copy CitationMedical Definition
presynaptic
adjective
pre·syn·ap·tic
-sə-ˈnap-tik
: 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
Love words? Need even more definitions?
Merriam-Webster unabridged
