Journal of Neuroscience, Vol 8, 4177-4183, Copyright © 1988 by Society for Neuroscience
Androgenic regulation of gap junctions between motoneurons in the rat spinal cord
A Matsumoto, AP Arnold, GA Zampighi and PE Micevych
Department of Anatomy, University of California, Los Angeles 90024.
Gap junctional plaques were found between androgen-sensitive motoneurons of
the spinal nucleus of the bulbocavernosus (SNB), using thin-section and
freeze-fracture techniques. The somata and proximal dendrites of SNB
motoneurons were studied after retrograde labeling with cholera toxin
conjugated to HRP. Of the gap junctions observed, 45% were somatodendritic,
35% were dendrodendritic, and 20% were somatosomatic. The removal of
testosterone by castration dramatically reduced the number and diameter of
the junctional plaques, and these changes were prevented by testosterone
treatment. The results are the first demonstration of hormonal regulation
of morphologically identified gap junctions in the CNS. The occurrence and
hormonal dependence of gap junctional plaques between motoneurons of the
lumbar spinal cord indicate that androgens regulate the degree of coupling
between these cells, which may allow for the synchronization and
amplification of the electrical activity in the nucleus.