Dianne McFarlane wants to find out.

Cushing’s disease is a common endocrine disease that affects approximately 15 percent of older horses and ponies. It is caused by degeneration of dopamine-producing neurons, similar to what occurs in people with Parkinson’s disease.

An Oklahoma State University Center for Veterinary Health Sciences team, lead by assistant professor Dianne McFarlane, DVM, PhD, ACVIM, ABVP, hopes that better understanding of age-related events that contribute to development of equine Cushing’s disease and also baboon age-associated dopaminergic neurodegeneration may provide useful comparisons in unraveling the cause of Parkinson’s disease.

McFarlane recently received a $600,000 grant from the National Institutes of Health (NIH) to fund a comparative medicine research project using horses and baboons.

McFarlane’s study “Initiating Factors of Neurodegeneration” seeks to determine the underlying factors that are responsible for causing neurodegeneration. Age is the major risk factor for neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease. However, it is unknown what biological changes occur as humans age that cause some but not all individuals to develop degenerative brain diseases.

“We will use a comparative approach, looking at two animal models,” explains McFarlane. “We chose not to induce disease but rather to study natural occurring disease processes to determine what events initiate the degeneration of dopamine-producing neurons in the central nervous system of humans. These are the neurons that degenerate when someone is suffering from Parkinson’s disease.”