 |
||||
|
||||
|
||||
|
||||
Previous Article | Next Article
Volume 17, Number 3, Issue of February 1, 1997 pp. 1122-1136
Copyright ©1997 Society for NeuroscienceEstrogen Induces Axonal Outgrowth in the Nucleus Retroambiguus-Lumbosacral Motoneuronal Pathway in the Adult Female Cat
Received July 11, 1996; revised Oct. 21, 1996; accepted Nov. 5, 1996.
Veronique G. J. M. VanderHorst and Gert Holstege Department of Anatomy and Embryology, Faculty of Medicine, University of Groningen, 9713 EZ Groningen, The Netherlands
In 1995, we discovered a new pathway in the cat, which originates from the nucleus retroambiguus (NRA) and terminates in a distinct set of lumbosacral hindlimb, axial, and pelvic floor motoneuronal cell groups [VanderHorst VGJM, Holstege G (1995) Caudal medullary pathways to lumbosacral motoneuronal cell groups in the cat: evidence for direct projections possibly representing the final common pathway for lordosis. J Comp Neurol 359:457-475]. The NRA is a compact group of interneurons located laterally in the caudal medulla oblongata. Its projection to lumbosacral motoneurons is thought to represent the final common pathway for male mounting and for female receptive or lordosis behavior. However, females only display lordosis behavior when they are in estrus, which suggests that the NRA-lumbosacral pathway is only active during estrus. This raised the question of whether estrogen affects this pathway. The effect of estrogen on the NRA-lumbosacral projection was studied light microscopically, using wheat-germ agglutinin horseradish peroxidase (WGA-HRP) as a tracer. The rubrospinal pathway served as control. The density of labeled NRA fibers in their target hindlimb motoneuronal cell groups appeared abundant in estrous and very weak in nonestrous cats. Such differences were not found in the rubrospinal pathway. For electron microscopical study, the NRA projection to the semimembranosus motoneuronal cell group was selected. In this cell group, an almost ninefold increase of labeled profiles was found in estrous versus nonestrous cats. Moreover, the semimembranous motoneuronal cell group contained labeled growth cones in estrous, but not in nonestrous, cats. The present study is the first to show that estrogen induces axonal outgrowth of a precisely identified pathway in the adult mammalian central nervous system. The possible mechanisms underlying this outgrowth are discussed.
Key words: estrogen; motoneuron; sexual behavior; spinal cord; nucleus retroambiguus; caudal medulla; cat; female; plasticity; sprouting; growth cone; ventral horn; lordosis behavior; sex steroid; WGA-HRP; hindlimb; muscle; semimembranosus; pelvic floor; iliopsoas; adductor longus; biceps femoris
This article has been cited by other articles:
N. Heldring, A. Pike, S. Andersson, J. Matthews, G. Cheng, J. Hartman, M. Tujague, A. Strom, E. Treuter, M. Warner, et al.
Estrogen Receptors: How Do They Signal and What Are Their Targets
Physiol Rev, July 1, 2007; 87(3): 905 - 931.
[Abstract] [Full Text] [PDF]
J. Boers, T. W. Ford, G. Holstege, and P. A. Kirkwood
Functional Heterogeneity Among Neurons in the Nucleus Retroambiguus With Lumbosacral Projections in Female Cats
J Neurophysiol, October 1, 2005; 94(4): 2617 - 2629.
[Abstract] [Full Text] [PDF]
L. Wang, S. Andersson, M. Warner, and J.-A. Gustafsson
Estrogen Actions in the Brain
Sci. Signal., June 25, 2002; 2002(138): pe29 - pe29.
[Abstract] [Full Text] [PDF]
P. O. Gerrits, C. Vodde, and G. Holstege
Retroambiguus Projections to the Cutaneus Trunci Motoneurons May Form a Pathway in the Central Control of Mating
J Neurophysiol, May 1, 2000; 83(5): 3076 - 3083.
[Abstract] [Full Text] [PDF]
R. Kraft, R. B. Levine, and L. L. Restifo
The Steroid Hormone 20-Hydroxyecdysone Enhances Neurite Growth of Drosophila Mushroom Body Neurons Isolated during Metamorphosis
J. Neurosci., November 1, 1998; 18(21): 8886 - 8899.
[Abstract] [Full Text] [PDF]
|
|
|
|
 |
|