Brain Energetics during Hypoxia and Ishemia

We are assessing brain oxygenation and energetics during acute hypoxia and ischemia.

Oxygenation is monitored using either electron paramagnetic resonance (link SWARTZ), microelectrodes or with flourescense lifetime measurements. Brain energetics are monitored using either 1H or 31P spectroscopy. Brain homeostasis is also studied using diffusion imaging.

We are examining the relationships between oxygenation, energy balance and cell volume regulation during hypoxia/ischemia (low oxygen/low blood flow). These conditions may occur in such different conditions as during a visit to high altitude, in the brain of a baby during a difficult childbirth, or during stroke or a heart attack.

Our spectroscopy program looks at the energetic status of brain under conditions of controlled hypoxia (low oxygen). We collaborate with the Dartmouth EPR center (Professor Harold Swartz) to obtain in vivo measurements of tissue oxygen over the time-course of our experiments. The figure shows phosphorus spectra during such a time-course. The inspired oxygen tensions are on the right, the individual spectra are shown in ascending order and the contour plot of the experiment is shown on the left. At low oxygen tensions, the highest peak (PCr) begins to decline and the inorganic phosphate (Pi) increases.