The Noll Physiological Research Center conducts research in basic, applied and clinical physiology. Its scientists promote an integrative physiology approach when possible and, while some small animal work is conducted, the majority of studies use human subjects. Common threads through much of our work include aging and/or exercise. The following provide some examples of the important questions being asked by Noll scientists and their students:
HEART FUNCTION AND AGE
How does aging effect cardiac contractility? A primary research focus of Dr. Korzick's laboratory is on the cellular regulation of cardiac contractile function by the a1-adrenergic nervous system in aged rat heart. Of particular interest is whether chronic endurance exercise training can reverse age-associated defects in a1-adrenergic-mediated contractile function. Central to the cardioprotective effect of exercise on the aged myocardium is the hypothesis that defects in protein kinase C (PKC) contribute, at least in part, to defective a1-adrenergic signaling. Thus an additional research focus includes measurement of PKC as it relates to training-induced cardioprotection and associated intracellular signal transduction mechanisms. Since important interactions between cardiac muscle and coronary vessels may influence training-induced cardioprotection, PKC signal transduction mechanisms are also studied in isolated coronary conduit arteries.
HUMAN THERMOREGULATION
How does normal healthy aging alter human thermoregulation and, in particular, cardiovascular aspects of thermoregulation? Dr. Kenney's research over the past 10-15 years has involved a systematic investigation of the effects of age, fitness, and gender on human temperature regulation and individuals' responses to heat stress. Present directions include examining control of skin blood flow as an effector response to hyperthermia and as part of integrated cardiovascular control during stress. He has developed a model using human subjects in which simultaneous estimate are made of blood flow to skin, the kidneys, and the splanchnic circulation under various stressful conditions. Effector control of skin blood flow is also examined by iontophoresing local receptor agonists and antagonists in order to better examine separate neural control systems. Gender questions have been expanded to include studies associated with menopause (specifically, effects of hormone replacement therapy.
AGING AND MUSCLE BLOOD FLOW
Does human aging alter the regulation of skeletal muscle blood flow during large muscle dynamic exercise? Dr. Proctor and his group are currently studying the leg blood flow responses to upright cycle ergometer exercise in healthy young and older men and women. They use catheter-based techniques (i.e., femoral vein and radial artery) to measure leg blood flow, arterial pressure, and for sampling blood. Their studies should contribute significantly to our understanding of the decline in physical function and increased incidence of chronic disease in older humans.
REPRODUCTIVE PHYSIOLOGY
Do energy deficits help explain exercise training induced changes in reproductive function? Dr. Willams and her students have most recently by examined the impact of negative energy balance created by dietary restriction combined with exercise, on reproductive function in collegiate female athletes. Their studies have specifically focused on the relationship between indications of an energy deficit and subtle, but clinically relevant changes in menstrual cyclicity that affect a large proportion of athletic women and recreational enthusiasts. Since previous studies conducted by Dr. Williams and colleagues in non-human primates have suggested that psychological stress can exacerbate the effects of a negative energy balance on reproductive function, Dr. Williams' laboratory has also begun to explore the interactions between psychological and metabolic stress on the menstrual cycle. The practical implication for this work is directed toward the prevention and treatment of clinical consequences of stress-induced reproductive abnormalities in humans including osteoporosis, delayed puberty, and infertility.
BLOOD PRESSURE CONTROL IN MICROGRAVITY
After returning from his 1998 Neurolab Space Shuttle Mission, Dr. Pawelczyk and his students have been studying: Effects of microgravity on neural control of blood pressure, 2. Countermeasures to be used in space to help avoid loss of cardiovascular control, 3. Neural causes of orthostatic intolerance in the elderly, 4. Sympathetic nervous system activity in the elderly as a cause of an altered insulin pulse profile, and 5. Effects of prolonged bed rest on the cardiovascular system and its regulation.
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