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Dr. John O'Brien

Dr. John O'Brien

Regular Member

The University of Texas Health Science Center at Houston

Medical School
Department of Ophthalmology and Visual Science

Signal transduction synaptic plasticity in the central nervous system entails a wide variety of mechanisms, encompassing both chemical and electrical synapses. Electrical synapses, composed of gap junctions, are a key component of neural circuitry throughout the CNS. Nowhere is this more apparent than in the vertebrate retina, where gap junctions play critical roles in neural processing. These include reducing noise at photoreceptor synapses, establishing receptive field sizes of many neurons, coordinating firing of spiking neurons, and establishing oscillations in neural networks. These functions are closely controlled during light adaptation, influencing the sensitivity and resolution of the retina, and accounting for a large part of the network plasticity.

A major focus of work in my lab is on revealing the molecular mechanisms that control network adaptation in the retina. Our previous work in this area included the discovery of the first predominantly neuron-specific gap junction protein (connexin 35/36), which is widely expressed throughout the retina and brain. We are examining how protein kinases and other cellular pathways modulate the opening and permeability of these gap junction channels, and how light adaptation drives these pathways. We are also exploring methods to manipulate these signaling pathways to close photoreceptor gap junctions and mitigate bystander killing in retinal degenerative diseases.

A tutorial in my lab would provide a broad-based experience in cellular and molecular neuroscience. Research projects may include in vitro and cell-based molecular and biochemical studies, biochemical studies in retina preparations, confocal microscopy, and transgenic zebrafish studies.



Medical School Faculty

Program Affiliations:

Program in Neuroscience

Program in Cell and Regulatory Biology

Contact Information

Phone: 713.500.5983


Office: MSB 7.242A

Title: Professor


Ph.D. - University of California-San Diego - 1991