Racial Differences in Vagal Control of Glucose Homeostasis

Obesity has a greater detrimental impact on the health of African American women (AAW) than on any other racial or gender group. Nearly 80% of AAW are overweight or obese. Reduced insulin sensitivity is more prevalent among AAW as compared to white women and men of both races. This condition puts AAW at increased risk for the development of type 2 diabetes mellitus. The exact mechanism underlying these pathophysiological differences remains unknown. The investigators have found that obese AAW have decreased parasympathetic nerve (PNS) activity compared to whites and recent studies in animal models showed that the PNS confers protection against oxidative stress. In our AA cohort, PNS activity was directly correlated with insulin sensitivity in obese AAW even after controlling for differences in age, blood pressure and visceral adiposity. Equally important, the investigators also showed that the decrease in insulin sensitivity was associated with increased oxidative stress as measured by plasma levels of F2-isoprostanes. Taken together these findings lead us to hypothesize that the decreased PNS activity in obese AAW compared to white women has deleterious effects on oxidative stress and insulin sensitivity.The investigators will test the hypothesis that acute central acetylcholinesterase inhibition will restore PNS activity and reduce oxidation in AAW compared to whites.