Cholecystokinin-8-like-immunoreactive fibers in rat lumbosacral autonomic regions are sexually dimorphic and altered by a reduction of androgen receptors |
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Authors: | Phan D C Newton B W |
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Affiliation: | Department of Anatomy and Center for Neuroscience, University of Arkansas for Medical Sciences, Little Rock 72205, USA. |
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Abstract: | Cholecystokinin-8-like-immunoreactive (CCK-8-LI) fibers in laminae VII and X of the rat lumbosacral spinal cord demarcate the position of preganglionic autonomic neurons. This investigation reveals that adult male Sprague-Dawley, or King-Holtzman/Sprague-Dawley rats contain more CCK-8-LI fibers in lumbosacral laminae VII and X than adult females. Furthermore, testicular feminization mutation male rats (which lack 85-90% of their functional androgen receptors) contain fewer CCK-8-LI fibers than normal male or female rats, with the amount of CCK-8-LI being reduced to a greater extent in the sympathetic vs. the parasympathetic regions of the lumbosacral spinal cord. Thus, CCK-8-LI in testicular feminization mutation male rats has a distinctly female-like pattern. These results suggest that testosterone is a regulatory factor for CCK-8-LI fibers found in laminae VII and X of the lumbosacral spinal cord. Sexual dimorphism in lumbosacral CCK-8-LI fibers may contribute to modulating the final common pathway which differentially regulates the reproductive organs and stereotypic reproductive behavior, and may be involved with the sex differences described for pain. |
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Keywords: | Autonomic nervous system Nociception Peptides Preganglionic Reproduction Spinal cord Testicular feminization mutation |
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