Physiology and function of glial cells Research in our laboratory focuses on the physiology of glial cells and on interactions between glia, neurons and blood vessels in the central nervous system. Glia have traditionally been viewed as passive, housekeeper cells in the brain. This view has been overturned in recent years as studies have demonstrated that glial cells have many essential functions in the CNS and may actively participate in information processing.We are studying several aspects of glial cell function, including i) neuronal activation of glial cells, ii) glial cell modulation of neuronal excitability and synaptic transmission, iii) calcium signaling within and between glial cells, and iv) glial cell regulation of blood flow.We have demonstrated that astrocytes and Müller cells, the two macroglial cells of the retina, generate both spontaneous and neuron-evoked calcium signals. These calcium signals, in turn, lead to the release of transmitters from glial cells, resulting in the modulation of neuronal excitability. We are currently studying how these glial signals affect information processing in the retina. We are also studying how pathology affects glial calcium signaling.We have shown that factors released from glial cells regulate blood flow in the retina. Light stimulation or direct activation of glial cells results in the release of arachidonic acid metabolites. Some of these metabolites constrict while others dilate vessels. We are studying how glia to vessel signaling is modulated and the role that glial cells play in controlling blood flow.We use the mammalian retina as a model system for studying glia-neuron-vessel interactions. Our work utilizes several retinal preparations, including the eyecup, whole-mount retina and dissociated single cells. Confocal imaging of glial cell Ca2+, imaging of ATP and glutamate release from glial cells, whole-cell patch-clamp recording and micro-ejection techniques are employed. We use transgenic mouse lines to study glial cell function in collaboration with Dr. Paulo Kofuji.
