Steven C. Hempleman


Phone: 928-523-7220
Office: Building 21 Room 402

Research/teaching interests

  • systemic physiology
  • cellular neurobiology
  • comparative animal physiology

Academic highlights

  • BS, PhD (Physiology), University of California, Davis, 1977, 1982
  • PhD: University of California , Davis, 1982
  • NIH Postdoctoral fellowship: University of California San Diego , 1982-1984
  • Assistant and Associate Professor: UCSD School of Medicine, 1985-1995
  • Assistant, Associate, and Full Professor: NAU Biology Department 1996-present


My lab studies the neurobiology of O2 and CO2 chemoreceptors--sensory neurons that are critical for normal breathing.  We concentrate on CO2 sensitive intrapulmonary chemoreceptors (IPC) found in bird lungs, and O2 and CO2 sensitive carotid body chemoreceptors found in birds and mammals.   Our scientific questions focus on sensory signal transduction: “How do respiratory chemoreceptor neurons detect changes in O2 and CO2 stimulus levels within the body and how do they produce action potentials that inform the brain of these changes?”

Our work has advanced understanding of O2 and CO2 chemoreceptor evolution and development in higher vertebrates, and may one day suggest improved medical and veterinary treatments for respiratory failure and other defects in chemoreceptor.

Respiratory chemoreceptors initiate life-sustaining breathing reflexes in response to a wide range of challenges, including high altitude, heat stress, cardiopulmonary disease, and exercise.  Birds in particular have a remarkable tolerance for low oxygen, low carbon dioxide, and high altitude. Some of this tolerance may result from their chemoreceptors providing a very strong drive to breathe.

Scientific techniques we use include in-vivo extracellular and intracellular voltage recording; in-vitro voltage-clamp, current-clamp, and fluorometric recording; computerized spike train analysis, peri-stimulus cycle triggered histograms, and mathematical modeling. Our work is funded by grants from the National Science Foundation, and the National Institutes of Health.