Dalton Cardiovascular Research Center

University of Missouri

James C. Schadt, PhD

Research Interests

Neurohumoral control of the heart and blood vessels

Research Description

Schadt's laboratory studies neurohumoral control of the cardiovascular system. Since integrative regulation of the cardiovascular system is either altered or absent in anesthetized or otherwise reduced preparations, a conscious-animal model is used in experiments. New Zealand white rabbits are prepared to permit chronic measurement of arterial and venous blood pressures, heart rate, cardiac output, regional blood flows and sympathetic nerve activity. Blood samples can be withdrawn to measure vasoactive compounds in the plasma. Research efforts have been concentrated on cardiovascular regulation during blood loss. Current studies are concentrated in two areas.

First, this laboratory is investigating the role of vasopressin in the response to blood loss. While this compound is generally thought of as a pressor agent, its release during blood loss does little to maintain arterial pressure or vascular resistance. This may be due to its release of the vasodilator, nitric oxide, from endothelial cells. Thus, vasopressin's vasoconstrictor properties may be opposed by its release of nitric oxide.

The second area of emphasis involves the effects of stress on cardiovascular control. Blood loss rarely occurs in a quiet laboratory. It is usually associated with increased sensory input, some of which is certainly stressful to the organism. While simultaneous stress extends the animals' ability to maintain blood pressure, once blood loss reaches a critical level, the response is similar with or without stress. Experiments are being conducted by Schadt's lab to define the mechanisms of this apparent increase in the resistance of the organism to the effects of blood loss. The goal of this research is to provide basic information about cardiovascular control in the conscious animal. The results of theses studies may ultimately provide information useful in the emergency medical management of traumatic blood loss in animals including humans.

Professional Background

• Obtained PhD from Texas Tech.
• Obtained MS from Indiana State.
• Obtained MS from Northern Illinois University.
• Obtained BS from Northern Illinois University.

Selected Publications