Date of Award


Degree Name

Master of Science


Animal Science

First Advisor

King, Sheryl


AN ABSTRACT OF THE THESIS OF Crystal Marie Welsh, for the Masters of Science degree in Equine Reproductive Physiology, presented on October 6, 2009, at Southern Illinois University Carbondale. TITLE: IMMUNOHISTOCHEMICAL IDENTIFICATION OF DOPAMINERGIC AND ADRENERGIC NERVES IN THE EQUINE OVARY MAJOR PROFESSOR: Dr. Sheryl S. King Dopamine (DA) appears to play a role in seasonal reproduction in the mare. We hypothesize that DA is delivered to the ovary by nerves. The objective of this study was to use immunohistochemical (IHC) localization to identify ovarian dopaminergic and adrenergic nerves. Ovaries were collected during anestrus (n=9) and cyclicity (n=11). Tissue was prepared for IHC using antibodies specific to tyrosine hydroxylase (TH) and dopamine beta hydroxylase (DβH). Microscopic evaluation was performed, comparing the numbers and distribution of TH– versus DβH–specific immunoreactive (IR) neurons. Catecholaminergic neurons were present in all ovaries. The preponderance (P<0.0001) of IR neurons were dopaminergic. Neurons were moderately dispersed throughout the ovarian medulla and lightly in the cortex. Moderate to heavy neuron density was also noted around blood vessels. Neither dopaminergic nor adrenergic neuron type was consistently associated with specific reproductive structures. These results indicate that catecholaminergic innervation does exist in the equine ovary. The presence of ovarian DA nerves supports our hypothesis that DA has a direct role in ovarian function in the equine, although the mechanism of this function requires further study.




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