Research Interest

The incidence of both obesity and hypertension continue to increase throughout many parts of the world. The primary focus of my research program is to discover and understand the neuroendocrine mechanisms by which energy homeostasis and cardiovascular function are regulated. We utilize chronically instrumented pre-clinical approaches (rodent models) to determine how metabolism, behavior and cardiovascular physiology respond to a number of nutrition and pharmacologic interventions. We are also able to advance our understanding of these problems via state of the art studies of mouse physiology. Since the discovery of leptin in 1994, there has been a remarkable advancement in our understanding of hypothalamic systems that regulate energy homeostasis. One of our main goals is to understand the biologic adaptations to weight loss to assist in developing more effective therapies for obesity.

Current Research

Mechanisms by which reduced energy consumption produces marked reductions in blood pressure and sympathetic activity. We use chronically instrumented rats to assess cardiovascular status while manipulating caloric intake. CNS lesions and microinjection strategies are employed to evaluate specific neuroanatomic and neurochemical substrates which modulate blood pressure during negative energy balance. In collaboration with Mike Rashotte, we are examining blood pressure, metabolic rate, and feeding responses to long term modulation of caloric availability or CNS infusion of peptides such as NPY.

Publications

Selected Publications

• Messina, M.M., S.A. Evans, S.J. Swoap, and J.M. Overton. Perinatal MSG treatment attenuates fasting-induced bradycardia and metabolic suppression. Physiology and Behavior: 86:324-330, 2005.
• Das, P., A.D. Parsons, J. Scarborough, J. Hoffman, J. Wilson, R.N. Thompson, J.M. Overton, D.A. Fadool. Electrophysiological and behavioral phenotype of insulin receptor defective mice. Physiology and Behavior: 86:287-296, 2005.
• Knight, W.D., S.J. Swoap, A.D. Parsons and J.M. Overton. Central thyrotropin-releasing hormone (TRH) infusion opposes the bradycardia induced by caloric restriction. Neuroendocrinology 83:69-76, 2006.
Messina, M.M., G. Boersma, J.M. Overton, and L.A. Eckel. Estradiol decreases the orexigenic effect of melanin-concentrating hormone in ovariectomized rats. Physiology and Behavior: 88: 523-528, 2006.
Messina, M.M. and J.M. Overton. Cardiovascular and metabolic action of chronic infusion of melanin-concentrating hormone. Reg Peptides 139:23-30, 2007.
S.J. Swoap, C. Li, J. Wess, A. D. Parsons, T. D. Williams, and J.M. Overton . Vagal tone dominates autonomic control of mouse heart rate at thermoneutrality. American Journal of Physiology: Heart and Circulatory Physiology 294: H1581-1588, 2008.