What does presynaptic mean?
Presynaptic means occurring before a synapse or belonging to the sending side of one. A synapse is a junction where one nerve cell communicates with another, usually by releasing chemical neurotransmitters from the presynaptic terminal into a small gap. Presynaptic structures therefore include the sending terminal, its membrane, and molecules that help regulate neurotransmitter release. The term is important in neuroscience and pharmacology because many drugs act by changing presynaptic activity: for example, they may alter how much neurotransmitter is released or block its reuptake. It should not be confused with postsynaptic, which describes the receiving side of the synapse. Although “synaptic” refers to synapses generally, “presynaptic” adds a precise anatomical and functional distinction between sending and receiving.
adjectiveLocated or occurring before a synapse, or relating to the nerve ending that sends signals across a synapse. In neuroscience, it commonly describes the presynaptic neuron, terminal, or membrane.
- Located at or before a synapse.
- Relating to the nerve ending or neuron that releases neurotransmitter across a synapse.
"The drug reduced neurotransmitter release by acting on presynaptic receptors."
"Presynaptic terminals contain vesicles filled with neurotransmitter."
"The researcher measured presynaptic calcium levels during stimulation."
A presynaptic ending is the messenger in a neuron-to-neuron conversation: it releases the chemical signal that the next cell receives.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of presynaptic
The word is formed from the prefix pre-, meaning “before,” and the adjective synaptic, which comes from synapse. Synapse derives from Greek synapsis, meaning “a connection” or “joining,” and ultimately from the Greek verb synaptein, “to join together.” The combining form syn- also expresses “together,” a sense preserved in terms such as synaptogenesis, the formation or development of synapses.
Related word forms
How presynaptic is actually used
This is primarily a technical term used in neuroscience, pharmacology, and related biomedical fields. It normally describes a neuron, terminal, membrane, receptor, or process rather than referring to information transmitted across a synapse in general.
Easily confused with presynaptic
Presynaptic structures send signals across a synapse, whereas postsynaptic structures receive them.
Synaptic means relating to a synapse generally, while presynaptic specifies the sending side or occurring before the synapse.