The Journal of Neuroscience, November 1, 1998, 18(21):8720-8729
Ciliary Neurotrophic Factor Receptor
in Spinal Motoneurons is
Regulated by Gonadal Hormones
Nancy G.
Forger1,
Christine K.
Wagner1,
Michael
Contois1,
Lynn
Bengston1, and
A. John
MacLennan2
1 Center for Neuroendocrine Studies and Department of
Psychology, University of Massachusetts, Amherst, Massachusetts 01003, and 2 Department of Neuroscience, University of Florida
Brain Institute, University of Florida College of Medicine,
Gainesville, Florida 32610
Ciliary neurotrophic factor receptor
(CNTFR
) is the
ligand-binding component of the CNTF receptor. CNTFR
expression is essential for the normal development of spinal motoneurons and is
required for the development of a sex difference in motoneuron number
in androgen-sensitive perineal motoneurons. We used immunocytochemistry to examine the expression and hormone regulation of CNTFR
protein in
the spinal nucleus of the bulbocavernosus (SNB), dorsolateral nucleus
and retrodorsolateral nucleus of the lower lumbar spinal cord of
adult rats. CNTFR
immunoreactivity (CNTFR
-IR) was observed in the somata and dendrites of virtually all motoneurons. In all three
motor pools, the intensity of motoneuron soma labeling was greatest
among gonadally intact males and was reduced in females and
gonadectomized males. The density of CNTFR
-IR in neuropil also
tended to be highest in intact males. Short-term (2 d) testosterone propionate treatment reversed the decline in the density of soma labeling in the SNB of castrated males but did not reverse any other
effects of castration. Long-term hormone treatment, achieved by
implanting males with testosterone capsules at the time of gonadectomy,
prevented the decline in soma labeling in all motor pools and partially
prevented the decline in neuropil label caused by castration. We
conclude that expression of CNTFR
protein is androgen-regulated in
spinal motoneurons.
Key words:
motoneuron; androgen; ciliary neurotrophic factor
receptor; spinal cord; immunocytochemistry; hormone
Copyright © 1998 Society for Neuroscience 0270-6474/98/18218720-10$05.00/0