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Gordon L. Fain, PhD
Distinguished Professor of the Departments of
Integrative Biology/Physiology and of Ophthalmology
Member of the Jules Stein Eye Institute
ReseaRch summaRy
Physiology of Photoreceptors
in the Vertebrate Eye
Dr. Fain’s primary research interest is in the physiology
of photoreceptors in the vertebrate eye. A vertebrate
photoreceptor uses a photopigment called rhodopsin
and a G-protein cascade to produce the electrical
response that signals a change in light intensity.
Powerful new techniques have made it possible to
understand the working of this cascade in extraordinary
detail. Practically all the protein molecules involved in
the cascade in a photoreceptor—from the pigment
molecule to the G-protein and channels, but also
including a large number of control proteins—are
expressed only in the photoreceptors and nowhere else
in the body. This has enabled scientists to use genetic
techniques to create mice in which these proteins
have been knocked out, over- or under-expressed, or
replaced with proteins of modified structure.
Dr. Fain’s laboratory uses electrical recording to study
the effects of such genetic alterations on the light
responses of mouse rods, in order to understand
the role of these proteins in the visual cascade. His
research team is especially interested in modulatory
enzymes and their function in light and dark adaptation.
Dr. Fain also has a long-standing interest in mechanisms
of photoreceptor degeneration in genetically
inherited disease. His laboratory is presently the only
laboratory measuring changes in calcium from mouse
rods with fluorescent dyes. Findings have implicated
both increases and decreases in calcium concentration
as contributing factors in the triggering of apoptosis.
Such information may provide insight into the mechanisms
of retinal degeneration.
36 Faculty | Fain
Research Grants
National Eye Institute: Physiology of Photoreceptors,
8/1/08–7/31/12