Ej. Nordeen et al., FIBROBLAST GROWTH FACTOR-2 STIMULATES CELL-PROLIFERATION AND DECREASES SEXUALLY DIMORPHIC CELL-DEATH IN AN AVIAN SONG CONTROL NUCLEUS, Journal of neurobiology, 37(4), 1998, pp. 573-581
The neural system controlling song in birds has proven a useful model
for investigating how neuronal growth and survival are regulated by se
xual differentiation. The present study focused on one song control ar
ea, the robust nucleus of the archistriatum (RA), and explored how sex
differences in the proliferation of putative glia cells in this regio
n influence sexually dimorphic cell survival. In zebra finches (Poephi
la guttata), RA neuron death is much greater in young females than in
males, resulting in marked sex differences in RA neuron number. An ear
lier study indicated that just prior to this sexually dimorphic neuron
death the proliferation of putative glia cells within the RA is signi
ficantly lower in females than in males and remains so throughout the
peak of neuron death. This suggests that sex differences in glia (or g
lia-derived molecules) might regulate neuron survival during sexual di
fferentiation of the RA. To determine whether increased cell prolifera
tion within the RA favors increased cell survival, we infused the pote
nt glia mitogen fibroblast growth factor-2 (FGF-2) into the RA unilate
rally in young females. We find that FGF-2 infusions increase RA cell
proliferation and concurrently decrease the incidence of degenerating
RA cells, results consistent with the hypothesis that glia exert neuro
trophic effects on RA neurons during sexual differentiation. (C) 1998
John Wiley & Sons, Inc.