Journal of Neuroscience, Vol 6, 3628-3633, Copyright © 1986 by Society for Neuroscience
Plasticity of expression of a synaptic vesicle antigen in adult rat superior cervical ganglion
KF Greif
The effects of deafferentation and alterations of synaptic activity on
levels of a synaptic vesicle-specific membrane protein (SV) were studied in
the adult rat superior cervical ganglion (SCG) in vivo, using a monoclonal
antibody directed against the protein. Levels of SV were quantified by
radioimmunoassay. Deafferentation of the SCG results in a transient
increase in SV levels in the SCG on days 7 and 10 after surgery, with
levels then dropping below control levels on days 14, 21, and 30 after
surgery. Immunohistochemical labeling of deafferented ganglia indicates
that the increase is confined to the perikarya of principal ganglionic
neurons. Levels of SV in an SCG target tissue, the iris, do not differ from
control levels on day 7 after deafferentation, but are elevated at days 10,
14, and 30 after surgery. After reinnervation of the SCG, levels of SV in
the SCG are elevated above control values, but do not differ from control
values in the iris. Treatment with chlorisondamine, which blocks synaptic
transmission in sympathetic ganglia, produces a significant increase in SV
levels in the SCG after 7 d of treatment. Long-term chlorisondamine
treatment results in reductions in SV in the SCG after 14 and 28 d.
Treatment with phenoxybenzamine for 6 d, which reflexly increases synaptic
activity, produces a marked decrease in SV in the SCG. These results
suggest that activity, mediated by transsynaptic factors, contributes to
the regulation of synthesis of a synaptic vesicle protein in the SCG. The
results further suggest that accumulation of synaptic vesicles in terminals
of the principal ganglion neurons may help regulate the maintenance of
normal synaptic vesicle pools within sympathetic neurons.