The Journal of Neuroscience, 2001, 21:RC127:1-5
RAPID COMMUNICATION
Targeting of Peptidergic Vesicles in Cotransmitting Terminals
Tuula
Karhunen,
Ferdinand S.
Vilim,
Vera
Alexeeva,
Klaudiusz
R.
Weiss, and
Paul J.
Church
Department of Physiology and Biophysics, Mount Sinai School of
Medicine, New York, New York 10029
In the present study, we examined the targeting of
neuropeptide-containing vesicles in terminals of neurons that release
both neuropeptides and classical transmitters. Single neurons were electrically stimulated with patterns of activity that were recorded in
freely behaving animals. The amount of peptide release was measured
biochemically using a radioimmunoassay, and the targeting of
peptidergic vesicles was quantified using immunoelectronmicroscopy. Repeated electrical stimulation of single neurons produced a very large
increase in peptide release. Peptide release is paralleled by a twofold
increase in the number of peptidergic vesicles docked at the portion of
the terminal membrane that is away from the target muscle. This is in
stark contrast to cholinergic vesicles, which aggregate at, and are
released from the conventional release sites in close apposition to the
muscle. This differential targeting of cholinergic and peptidergic
vesicles may play a significant role in the distinct release
requirements and spatial and temporal characteristics of the actions of
conventional and peptidergic transmitters.
Key words:
cotransmission; synaptic transmission; peptide; presynaptic terminal; facilitation; DCV; LDCV
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