going before another in time or order I'd like to follow up on an antecedent question from another reporter Synonyms previous, anterior, foregoing, former, precedent, preceding, priorRelated Words advance, early, premature; earliest, first, inaugural, initial, maiden, original, pioneer; preexisting; introductory, preliminary; erstwhile, whilomNear ...
Neurotransmitters are formed in a presynaptic neuron and stored in small membrane-bound sacks, called vesicles, inside this neuron. When this neuron is activated, these intracellular vesicles fuse with the cell membrane and release their contents into the synapse, a process called exocytosis.
In the synaptic region, the plasma membrane of the presynaptic cell is specialized for vesicle exocytosis; synaptic vesicles, which contain a neurotransmitter, are clustered in these regions. The opposing membrane of the postsynaptic cell (in this case, a neuron) contains receptors for the neurotransmitter. Figure 21-30, Lodish 4th edition. Micrograph of an axon terminal obtained by the rapid-freezing deep-etch technique.