Home > Program Faculty >Barbara Morgan Laboratory
The primary interest of the Morgan laboratory concerns the neural control of circulation, with special emphasis on pulmonary-cardiovascular interactions. Most current research is aimed at understanding how changes in respiratory activity (e.g. apneas and other chemoreflex perturbations, alterations in airway resistance, central respiratory drive and work of breathing) affect the cardiovascular system.
Using an integrative physiology approach, the effects of breathing are investigated on sympathetic activity, limb blood flow, and cerebral blood flow in human subjects. Current areas of active interest include (active collaborations are indicated in parentheses):
- sleep disordered breathing and the cardiovascular system: influence
of pulmonary stretch receptors
on sympathetic outflow to skeletal muscle (Skatrud, Dempsey) acute effects of sleep-induced
periodic breathing on the cerebral circulation (Skatrud) effects of arousal from sleep on cerebral
blood flow in healthy subjects (Skatrud) effects of nocturnal hypoxic exposure on cerebrovascular endothelial function (Skatrud) role of cerebrovascular endothelial dysfunction in causing sleep disordered breathing (Skatrud, Dempsey).
- influence of respiratory muscle work on redistribution of the cardiac
output during exercise:
respiratory muscle metaboreflex effects on sympathetic outflow and vascular resistance in the resting limb (Dempsey) effects of mechanical ventilation on cardiac output at rest and during exercise in patients with chronic heart failure (Dempsey).
LeMarbre, G., S. Stauber, R.N. Khayat, D.S. Puleo, J.B. Skatrud, and B.J. Morgan. Baroreflex-induced sympathetic activation does not alter cerebrovascular CO2 responsiveness in humans. Journal of Physiology 551:609-616, 2003.
Przybylowski, T., M.-F. Bangash, K. Reichmuth, B.J. Morgan, J.B. Skatrud, and J.A. Dempsey: Mechanisms of the cerebrovascular response to apnoea. Journal of Physiology 548:323-332, 2003.
Derchak, P.A., A.W. Sheel, B.J. Morgan, D.F. Pegelow, and J.A. Dempsey. Fatiguing expiratory muscle work causes a reflex increase in muscle sympathetic nerve activity. Journal of Applied Physiology 92:1539-1552, 2002.
Sheel A.W., P.A. Derchak, B.J. Morgan, D.F.Pegelow, A.J. Jacques, J.A. Dempsey. Fatiguing inspiratory muscle work causes reflex reduction in resting leg blood flow in humans.
J Physiol. 537:277-89, 2001 [Full Text]Xie, A., J.B. Skatrud, D.S. Puleo, B.J. Morgan. Exposure to hypoxia produces long-lasting sympathetic activation in humans. J Appl Physiol. 91:1555-62, 2001 [Full Text]
Sherry, J.E., K.M. Oehrlein, K.S. Hegge, and B.J. Morgan. Effects of burst mode transcutaneous electrical nerve stimulation on peripheral vascular resistance. Physical Therapy 81:1183-1191, 2001.
St. Croix, C.M., B.J. Morgan, T.J. Wetter, and J.A. Dempsey: Fatiguing respiratory muscle work causes reflex sympathetic activation in humans. Journal of Physiology 529:493-504, 2000.
Xie, A., J.B. Skatrud D.C. Crabtree, D.S. Puleo, B.M. Goodman, and B.J. Morgan: Neurocirculatory consequences of intermittent asphyxia in humans. Journal of Applied Physiology 89:1333-1339, 2000.
Miller, B.F., Gruben, K.G., and B.J. Morgan: Circulatory responses to voluntary and electrically induced muscle contractions in humans. Physical Therapy 80:53-59, 2000.
St. Croix, C.M., M. Satoh, B.J. Morgan, J.B. Skatrud, and J.A. Dempsey: Role of respiratory motor output in within-breath modulation of muscle sympathetic nerve activity in humans. Circulation Research 85:457-469, 1999.
Arabi, Y., B.J. Morgan, B. Goodman, D.S. Puleo, A. Xie, and J.B. Skatrud: Daytime blood pressure elevation following nocturnal hypoxia.
Journal of Applied Physiology 87:689-698, 1999.Xie, A., J.B. Skatrud, D.S. Puleo, and B.J. Morgan: Arousal from sleep shortens sympathetic burst latency in humans. Journal of Physiology 515:621-628, 1999.
Morgan, B.J., J.A. Dempsey, D. Pegelow, A. Jacques, L. Finn, M. Palta, J.B. Skatrud, and T.B. Young: Blood pressure perturbations caused by subclinical sleep disordered breathing.
Sleep 21:737-746, 1998.Katragadda, S., A. Xie, D.S. Puleo, J.B. Skatrud, and B.J. Morgan: Neural mechanism of the pressor response to obstructive and non-obstructive apnea. Journal of Applied Physiology 83:2048-2054, 1997.