Selva Baltan Tekkok, MD, PhD
Research Assistant Professor, Department of Neurology
My research focuses on mechanisms of brain cell damage following stroke in white matter. Experimental approaches include optic nerve and brain slice models, together with electrophysiological recordings and advanced optical microscopy techniques such as fluorescence immunocytochemistry, and confocal microscopy. Relatively little is known about how white matter injury occurs during hypoxic/ischemic, traumatic or demyelinating disorders. We discovered that glutamate, which was accepted to be an exclusive gray matter neurotransmitter, is indeed released in white matter during injury. Surprisingly, overactivation of glutamate receptors is toxic not only to neurons, but also to oligodendrocytes, the myelin-forming glial cells. We also investigate the mechanisms of axonal injury in the same preparations to identify the intimate relationship between oligodendrocytes and their myelinated axons. In addition, we study the role of glucose and glycogen stores in white matter during anoxic/ischemic injury. We showed that, during aglycemia, glycogen is converted to lactate and can be used as an alternative fuel by axons to maintain function. Moreover, glycogen stores could be modified in white matter through insulin-receptor dependent and independent mechanisms, which may offer beneficial effects on recovery after anoxic/ischemic injury.