Cerebral tissue pO 2 response to stimulation is preserved with age in awake mice

• Published in: Neuroscience letters Vol. 699; p. 160
• Main Authors: Moeini, Mohammad, Lu, Xuecong, Bélanger, Samuel, Picard, Frédéric, Boas, David, Kakkar, Ashok, Lesage, Frédéric
• Format: Journal Article
• Language: English
• Published: Ireland 23.04.2019
• Subjects: Aging - metabolism; Aging - physiology; Animals; Brain - cytology; Brain - metabolism; Male; Mice; Neurons - physiology; Oxygen Consumption; Vibrissae - physiology; Wakefulness; Aging; Awake mice; Two-photon microscopy; Neural stimulation; Cerebral tissue oxygenation
• ISSN: 1872-7972
• DOI: 10.1016/j.neulet.2019.02.007

Compromised oxygen supply to cerebral tissue could be an important mechanism contributing to age-related cognition decline. We recently showed in awake mice that resting cerebral tissue pO decreases with age, a phenomenon that manifests mainly after middle-age. To extend these findings, here we aimed to study how tissue pO response to neuronal stimulation is affected by aging. We used two-photon phosphorescence lifetime microscopy to directly measure the brain tissue pO response to whisker stimulation in healthy awake young, middle-aged and old mice. We show that despite a decrease in baseline tissue pO , the amplitude of the tissue pO response to stimulation is well preserved with age. However, the response dynamics are altered towards a slower response with reduced post-stimulus undershoot in older ages, possibly due to stiffer vessel wall among other factors. An estimation of the net oxygen consumption rate using a modified Krogh model suggests that the O overshoot during stimulation may be necessary to secure a higher capillary O delivery to the tissue proportional to increased CMRO to maintain the capillary tissue pO . It was observed that the coupling between the CMRO and capillary O delivery is preserved with age.