Frank L. Powell is a physiologist and Professor of Medicine at UC San Diego, where he has been since 1980. He obtained his Ph.D. in respiratory and comparative physiology at UC Davis in 1978 and did pre- and post-doctoral training at the Max Planck Institute for Experimental Medicine in Gottingen, Germany. His early research focused on respiratory gas exchange, including factors that limit gas exchange for oxygen and other gases, breath testing, and defining the mechanisms responsible for better oxygen exchange at high altitude in birds compared to mammals.
Currently, our laboratory is focused on determining the mechanisms of neural plasticity and ventilatory acclimatization with chronic hypoxia. Chronic hypoxia occurs with chronic lung disease and at high altitude (sustained hypoxia) and with sleep apnea (intermittent hypoxia). We especially focus on mechanisms of susceptibility and tolerance to chronic hypoxia in the central nervous system (CNS) circuits that control breathing. Our recent experiments study:
- The importance of genes, which have been shown to be important for hypoxic tolerance in Drosophila selected for low O2 (e.g. Notch pathway genes), in mice.
- The role of signaling pathways, which are known to be important for plasticity in intermittent hypoxia (e.g. ROS, TrkB), in plasticity with chronic sustained hypoxia.
- The effects of HIF-1α versus HIF-2α in neurons versus glia for plasticity in the CSN with chronic hypoxia.
- Interactions between HIF, FIH and Notch in chronic hypoxia.
- The role of inflammatory signals in acclimatization to chronic hypoxia.
- Neural plasticity with chronic hypoxia in animal models of lung disease (vs. environmental hypoxia).
We study the problem at multiple levels, translating from genetic and molecular mechanisms to the whole animal physiology. Experimental approaches include:
- ventilatory responses, respiratory gas exchange and functional MRI in healthy humans during acclimatization to hypoxia at high altitude, and in patients with sleep apnea receiving various treatments,
- measuring ventilatory responses, metabolism and respiratory muscle activity in conscious, freely moving, instrumented rats and transgenic mice,
- temporally and spatially specific gene deletion using loxP-Cre strategies in transgenic mice,
- neurophysiological studies of chemoreceptor reflexes in anesthetized rats and mice
- in vivo and confocal fluorescent imaging, immunohistochemistry and molecular biological measures of signals for neural plasticity.
Our laboratory also continues to make in gas exchange measurements in humans and various animal models. These studies are generally focused on gas exchange limitations (diffusion limitation, ventilation-perfusion heterogeneity), breath testing and blood sampling (non-invasive measures of gas levels in blood), and comparative physiology (animal models of human gas exchange and lung disease).
Powell's teaching efforts have been focused in the UCSD School of Medicine and Pharmaceutical Sciences. Currently, he is the director of interdisciplinary courses on the Pulmonary System for first and second year in the new UCSD School of Medicine curriculum. Powell also teaches in the Physiology track of the Biomedical Sciences Ph.D. program and supports professional training in physiology and educational outreach through the American Physiological Society. He also directs an NIH institutional training grant in Respiratory Biology, which is a new collaboration with the Division of Pulmonary and Critical Care.