Journal of Neuroscience, Vol 7, 904-912, Copyright © 1987 by Society for Neuroscience
Development and regulation of dendrites in the rat superior cervical ganglion
JT Voyvodic
Intracellular injection of HRP was used to study the postnatal development
of dendrites in the rat superior cervical ganglion (SCG). This study had 2
goals: to describe the growth of dendrites during normal development and to
determine the influence of preganglionic innervation on dendritic growth.
At birth, ganglion cell morphology is relatively simple; cells have few
dendritic branches and an average total dendritic length under 300 micron.
In the first postnatal month there is a 4-fold increase in dendritic length
and a marked increase in the complexity of branching. Dendrites continue to
grow into adulthood; at each age studied (up to 16 months old), the
dendritic geometries of SCG cells became progressively more extensive and
complex. The influence of innervation on the development of dendrites was
assessed by cutting the cervical sympathetic trunk (CST) within a day of
birth; reinnervation was prevented by ligating and displacing the proximal
end of the CST. During the first postnatal month, the cells in denervated
ganglia showed an increase in dendritic length indistinguishable from that
seen in unoperated control ganglia. The rate of growth after 1 month was
somewhat slower in experimental animals than in controls; nevertheless, the
dendrites of cells in denervated ganglia showed progressively larger arbors
at each time point measured. These results indicate that in the SCG the
majority of dendritic growth occurs postnatally, dendrites continue to grow
in adult rats, and dendritic growth is largely independent of the presence
of preganglionic innervation. The significance of these findings for the
regulation of innervation in this part of the nervous system is discussed.