My primary research interest is focused on the vertebrate retina, a unique, well organized neural network that carries out sophisticated computations on the visual image. Four general areas occupy most of my experimental efforts. The first relates to the mechanisms of synaptic transmission in the retina, with special emphasis on glutamate receptors. Second, I have a long-standing interest in the relationships between structure and function and this had led to computational approaches to these problems, including the use of computer simulations to replicate physiological observations. In recent years my colleagues and I have developed models of multichannel impulse encoding, the role of T-type calcium channels in dendritic integration and impulse generation and the role of NMDA and AMPA receptors in synaptic transmission. A third area involves the use of fluorescent dyes to study functional properties of cells, including the use of activity-dependent dyes, combined with confocal microscopy and dyes to study intracellular calcium, pH, and chloride activity. A fourth research area relates to the function of glial cells in the retina, principally the Müller cells and how they generate calcium waves and respond to externally applied NAD.
Methods used in my laboratory include intracellular, whole-cell and patch-electrode electrophysiological techniques applied to the intact retina, retinal slices, and dissociated cells. Optical techniques include fluorescence microscopy, confocal microscopy, and 3D image reconstruction techniques. We are adding two-photon, confocal microscopy to combine this with electrophysiology for analyzing intricate properties of dendrites. We also use high-speed computers with specialized software (Neuron and MCell) to carry out studies of single cell structure and function relationships, including diffusion of neurotransmitter and receptor kinetics.
Boycott Award for research (2002)
2008 Proctor Medal Award from the Association for Research in Vision and Ophthalmology
(For a comprehensive list of recent publications, refer to PubMed, a service provided by the National Library of Medicine.)
- Lockridge AD, Baumann DC, Akhaphong B, Abrenica A, Miller RF, Alejandro EU. Serine racemase is expressed in islets and contributes to the regulation of glucose homeostasis. Islets. 2016;8(6):195-206.
- Gustafson EG, Stevens ES, Miller RF. Dynamic regulation of D-serine release in the vertebrate retina. J Physiol. 2015;593(4):843-56.
- Romero GE, Lockridge AD, Morgans CW, Bandyopadhyay D, Miller RF. The postnatal development of D-serine in the retinas of two mouse strains, including a mutant mouse with a deficiency in D-amino acid oxidase and a serine racemase knockout mouse. ACS Chem Neurosci. 2014;5(9):848-54.
- Gustafson EC, Morgans CW, Tekmen M, Sullivan SJ, Esguerra M, Konno R, Miller RF. Retinal NMDA receptor function and expression are altered in a mouse lacking D-amino acid oxidase. J Neurophysiol. 2013;110(12):2718-26.
- Sullivan SJ, Miller RF. AMPA receptor-dependent, light-evoked D-serine release acts on retinal ganglion cell NMDA receptors. J Neurophysiol. 2012;108(4):1044-51.
- Sullivan SJ, Esguerra M, Wickham RJ, Romero GE, Coyle JT, Miller RF. Serine racemase deletion abolishes light-evoked NMDA receptor currents in retinal ganglion cells. J Physiol. 2011;589(Pt 24):5997-6006.
- Sullivan SJ, Miller RF. AMPA receptor mediated D-serine release from retinal glial cells. J Neurochem. 2010;115(6):1681-9.
- Stevens ER, Gustafson EC, Miller RF. Glycine transport accounts for the differential role of glycine vs. D-serine at NMDA receptor coagonist sites in the salamander retina. Eur J Neurosci. 2010;31(5):808-16.
- Stevens ER, Gustafson EC, Sullivan SJ, Esguerra M, Miller RF. Light-evoked NMDA receptor-mediated currents are reduced by blocking D-serine synthesis in the salamander retina. Neuroreport. 2010;21(4):239-44.
- Reed BT, Sullivan SJ, Tsai G, Coyle JT, Esguerra M, Miller RF.The glycine transporter GlyT1 controls N-methyl-D-aspartic acid receptor coagonist occupancy in the mouse retina. Eur J Neurosci. 2009;30(12):2308-17.
Current Graduate Students:
Nathalia Torres Jimenez (Neuroscience, University of Minnesota).
Former Graduate Students:
Steve Sullivan (Ph.D. 2011, Neuroscience, University of Minnesota).
Eric Gustafson (Ph.D. 2009, Neuroscience, University of Minnesota).
Eric Stevens (Ph.D. 2007, Neuroscience, University of Minnesota).
Dori Henderson (Ph.D. 2001, Neuroscience, University of Minnesota).
Toby Velte (Ph.D. 1995, Neuroscience, University of Minnesota).
Weifeng Yu (Ph.D., Physiology, 1994). Postdoctoral Fellow, Department of Physiology, Johns Hopkins University, School of Medicine, Baltimore, MD.