Full metadata
Title
Seasonal changes in cell neogenesis in the brain and pituitary gland: a study in the adult male frog, Rana catesbeiana
Description
Though for most of the twentieth century, dogma held that the adult brain was post-mitotic, it is now known that adult neurogenesis is widespread among vertebrates, from fish, amphibians, reptiles and birds to mammals including humans. Seasonal changes in adult neurogenesis are well characterized in the song control system of song birds, and have been found in seasonally breeding mammals as well. In contrast to more derived vertebrates, such as mammals, where adult neurogenesis is restricted primarily to the olfactory bulb and the dentate gyrus of the hippocampus, neurogenesis is widespread along the ventricles of adult amphibians. I hypothesized that seasonal changes in adult amphibian brain cell proliferation and survival are a potential regulator of reproductive neuroendocrine function. Adult, male American bullfrogs (Rana catesbeiana; aka Lithobates catesbeianus), were maintained in captivity for up to a year under season-appropriate photoperiod. Analysis of hormone levels indicated seasonal changes in plasma testosterone concentration consistent with field studies. Using the thymidine analogue 5-bromo-2-deoxyuridine (BrdU) as a marker for newly generated cells, two differentially regulated aspects of brain cell neogenesis were tracked; that is, proliferation and survival. Seasonal differences were found in BrdU labeling in several brain areas, including the olfactory bulb, medial pallium, nucleus accumbens and the infundibular hypothalamus. Clear seasonal differences were also found in the pars distalis region of the pituitary gland, an important component of neuroendocrine pathways. BrdU labeling was also examined in relation to two neuropeptides important for amphibian reproduction: arginine vasotocin and gonadotropin releasing hormone. No cells co-localized with BrdU and either neuropeptide, but new born cells were found in close proximity to neuropeptide-containing neurons. These data suggest that seasonal differences in brain and pituitary gland cell neogenesis are a potential neuroendocrine regulatory mechanism.
Date Created
2012
Contributors
- Mumaw, Luke (Author)
- Orchinik, Miles (Thesis advisor)
- Deviche, Pierre (Committee member)
- Chandler, Douglas (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
x, 70 p. : ill. (some col.)
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.15161
Statement of Responsibility
by Luke Mumaw
Description Source
Retrieved on July 25, 2013
Level of coding
full
Note
thesis
Partial requirement for: M.S., Arizona State University, 2012
bibliography
Includes bibliographical references (p. 43-54)
Field of study: Biology
System Created
- 2012-08-24 06:31:15
System Modified
- 2021-08-30 01:45:19
- 3 years 2 months ago
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