Date of Award
2006
Degree Type
Thesis
Degree Name
Master of Science
Program
Neuroscience
Supervisor
Dr. Scott MacDougall-Shackleton
Abstract
One or more of three distinct forms of gonadotropin releasing hormones (GnRHs), has been found in all vertebrates studied. Birds are known to contain three types of GnRH, chicken GnRH-I and -II (cGnRH-I and -II) and lamprey GnRH-III, but to date nobody has investigated the distribution of GnRH-II in a songbird species. Thus, one objective of this thesis was to investigate the anatomical distribution of GnRH-II in the male house sparrow brain (Passer domesticus). Furthermore, songbirds possess a neural circuitry involved in the production of complex vocalizations called “song”. Previous studies identified lamprey GnRH-III (IGnRH-III) in specific brain area involved with song perception and production. The second objective of this thesis was to determine whether GnRH-II is located in nuclei associated with song perception and/or production. GnRH-II has been demonstrated to increase sexual receptivity in many vertebrate species, including mammals and birds. In previous studies, I conducted demonstrated that when female house sparrows are group housed with male house sparrows, there are significantly higher amounts of immunoreactive GnRH-II throughout the brain compared to females group housed with other females. The last objective in this thesis was to determine the effect of reproductive context on the amount of neural GnRH-II immunoreactivity in female house sparrows. I found that there was significant variation in immunoreactive GnRH-II when females were housed with males in breeding or nonbreeding conditions. Females housed with only auditory stimulation from a nonbreeding male had significantly greater amounts immunoreactive GnRH-II staining compared to females housed with visual and auditory cues from a breeding male and females with visual and auditory cues from a nonbreeding male
Recommended Citation
Stevenson, Tyler John, "DISTRIBUTION AND REPRODUCTIVE CONTEXT OF IMMUNOREACTIVE GONADOTROPIN RELEASING-HORMONE - Il IN THE SONGBIRD BRAIN" (2006). Digitized Theses. 5039.
https://ir.lib.uwo.ca/digitizedtheses/5039
