Search results
Results from the WOW.Com Content Network
Once released, a neurotransmitter enters the synapse and encounters receptors. Neurotransmitter receptors can either be ionotropic or g protein coupled. Ionotropic receptors allow for ions to pass through when agonized by a ligand. The main model involves a receptor composed of multiple subunits that allow for coordination of ion preference.
It may occur via direct contact between cells (i.e., via gap junctions), as in an electrical synapse, but most commonly occurs via the vesicular release of neurotransmitters from the presynaptic axon terminal into the synaptic cleft, as in a chemical synapse. [2]
In addition, a synapse serves as a junction where both the transmission and processing of information occur, making it a vital means of communication between neurons. [ 10 ] At the synapse, the plasma membrane of the signal-passing neuron (the presynaptic neuron) comes into close apposition with the membrane of the target ( postsynaptic ) cell.
In a neuron, synaptic vesicles (or neurotransmitter vesicles) store various neurotransmitters that are released at the synapse. The release is regulated by a voltage-dependent calcium channel . Vesicles are essential for propagating nerve impulses between neurons and are constantly recreated by the cell .
The release of a neurotransmitter is triggered by the arrival of a nerve impulse (or action potential) and occurs through an unusually rapid process of cellular secretion . Within the presynaptic nerve terminal, vesicles containing neurotransmitter are localized near the synaptic membrane.
After being released into the synaptic cleft, neurotransmitters diffuse across the synapse where they are able to interact with receptors on the target cell. The effect of the neurotransmitter is dependent on the identity of the target cell's receptors present at the synapse.
Neurotransmitters are released into a synapse in packaged vesicles called quanta. One quantum generates a miniature end plate potential (MEPP) which is the smallest amount of stimulation that one neuron can send to another neuron. [1] Quantal release is the mechanism by which most traditional endogenous neurotransmitters are transmitted ...
Illustration of the major elements in chemical synaptic transmission. An electrochemical wave called an action potential travels along the axon of a neuron.When the wave reaches a synapse, it provokes release of a puff of neurotransmitter molecules, which bind to chemical receptor molecules located in the membrane of another neuron, on the opposite side of the synapse.