Biomaterial Database

Molecular mechanisms of vertebrate photoreceptor light adaptation. 1999

E N Pugh, and S Nikonov, and T D Lamb

FM Kirby Center for Molecular Ophthalmology, Department of Ophthalmology, Institute of Neurological Sciences, Stellar-Chance Laboratories, University of Pennsylvania, 422 Curie Boulevard, Philadelphia, Pennsylvania 19104-6069, USA. pugh@psych.upenn.edu

An important recent advance in the understanding of vertebrate photoreceptor light adaptation has come from the discovery that as many as eight distinct molecular mechanisms may be involved, and the realization that one of the principal mechanisms is not dependent on calcium. Quantitative analysis of these mechanisms is providing new insights into the nature of rod photoreceptor light adaptation.

UI	MeSH Term	Description	Entries
D002147	Calmodulin	A heat-stable, low-molecular-weight activator protein found mainly in the brain and heart. The binding of calcium ions to this protein allows this protein to bind to cyclic nucleotide phosphodiesterases and to adenyl cyclase with subsequent activation. Thereby this protein modulates cyclic AMP and cyclic GMP levels.	Calcium-Dependent Activator Protein,Calcium-Dependent Regulator,Bovine Activator Protein,Cyclic AMP-Phosphodiesterase Activator,Phosphodiesterase Activating Factor,Phosphodiesterase Activator Protein,Phosphodiesterase Protein Activator,Regulator, Calcium-Dependent,AMP-Phosphodiesterase Activator, Cyclic,Activating Factor, Phosphodiesterase,Activator Protein, Bovine,Activator Protein, Calcium-Dependent,Activator Protein, Phosphodiesterase,Activator, Cyclic AMP-Phosphodiesterase,Activator, Phosphodiesterase Protein,Calcium Dependent Activator Protein,Calcium Dependent Regulator,Cyclic AMP Phosphodiesterase Activator,Factor, Phosphodiesterase Activating,Protein Activator, Phosphodiesterase,Protein, Bovine Activator,Protein, Calcium-Dependent Activator,Protein, Phosphodiesterase Activator,Regulator, Calcium Dependent
D006152	Cyclic GMP	Guanosine cyclic 3',5'-(hydrogen phosphate). A guanine nucleotide containing one phosphate group which is esterified to the sugar moiety in both the 3'- and 5'-positions. It is a cellular regulatory agent and has been described as a second messenger. Its levels increase in response to a variety of hormones, including acetylcholine, insulin, and oxytocin and it has been found to activate specific protein kinases. (From Merck Index, 11th ed)	Guanosine Cyclic 3',5'-Monophosphate,Guanosine Cyclic 3,5 Monophosphate,Guanosine Cyclic Monophosphate,Guanosine Cyclic-3',5'-Monophosphate,3',5'-Monophosphate, Guanosine Cyclic,Cyclic 3',5'-Monophosphate, Guanosine,Cyclic Monophosphate, Guanosine,Cyclic-3',5'-Monophosphate, Guanosine,GMP, Cyclic,Guanosine Cyclic 3',5' Monophosphate,Monophosphate, Guanosine Cyclic
D006162	Guanylate Cyclase	An enzyme that catalyzes the conversion of GTP to 3',5'-cyclic GMP and pyrophosphate. It also acts on ITP and dGTP. (From Enzyme Nomenclature, 1992) EC 4.6.1.2.	Guanyl Cyclase,Deoxyguanylate Cyclase,Guanylyl Cyclase,Inosinate Cyclase,Cyclase, Deoxyguanylate,Cyclase, Guanyl,Cyclase, Guanylate,Cyclase, Guanylyl,Cyclase, Inosinate
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000221	Adaptation, Ocular	The adjustment of the eye to variations in the intensity of light. Light adaptation is the adjustment of the eye when the light threshold is increased; DARK ADAPTATION when the light is greatly reduced. (From Cline et al., Dictionary of Visual Science, 4th ed)	Light Adaptation,Adaptation, Light,Adaptations, Light,Adaptations, Ocular,Light Adaptations,Ocular Adaptation,Ocular Adaptations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D015398	Signal Transduction	The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.	Cell Signaling,Receptor-Mediated Signal Transduction,Signal Pathways,Receptor Mediated Signal Transduction,Signal Transduction Pathways,Signal Transduction Systems,Pathway, Signal,Pathway, Signal Transduction,Pathways, Signal,Pathways, Signal Transduction,Receptor-Mediated Signal Transductions,Signal Pathway,Signal Transduction Pathway,Signal Transduction System,Signal Transduction, Receptor-Mediated,Signal Transductions,Signal Transductions, Receptor-Mediated,System, Signal Transduction,Systems, Signal Transduction,Transduction, Signal,Transductions, Signal
D017948	Retinal Rod Photoreceptor Cells	Photosensitive afferent neurons located in the peripheral retina, with their density increases radially away from the FOVEA CENTRALIS. Being much more sensitive to light than the RETINAL CONE CELLS, the rod cells are responsible for twilight vision (at scotopic intensities) as well as peripheral vision, but provide no color discrimination.	Photoreceptors, Rod,Retinal Rod Cells,Rod Photoreceptors,Rods (Retina),Retinal Rod,Retinal Rod Cell,Retinal Rod Photoreceptor,Retinal Rod Photoreceptors,Rod Photoreceptor Cells,Cell, Retinal Rod,Cell, Rod Photoreceptor,Cells, Retinal Rod,Cells, Rod Photoreceptor,Photoreceptor Cell, Rod,Photoreceptor Cells, Rod,Photoreceptor, Retinal Rod,Photoreceptor, Rod,Photoreceptors, Retinal Rod,Retinal Rods,Rod (Retina),Rod Cell, Retinal,Rod Cells, Retinal,Rod Photoreceptor,Rod Photoreceptor Cell,Rod Photoreceptor, Retinal,Rod Photoreceptors, Retinal,Rod, Retinal,Rods, Retinal
D020419	Photoreceptor Cells, Vertebrate	Specialized PHOTOTRANSDUCTION neurons in the vertebrates, such as the RETINAL ROD CELLS and the RETINAL CONE CELLS. Non-visual photoreceptor neurons have been reported in the deep brain, the PINEAL GLAND and organs of the circadian system.	Retinal Photoreceptor Cells,Rods and Cones,Photoreceptors, Retinal,Photoreceptors, Vertebrate,Retinal Photoreceptors,Vertebrate Photoreceptor Cells,Vertebrate Photoreceptors,Cell, Retinal Photoreceptor,Cell, Vertebrate Photoreceptor,Cells, Retinal Photoreceptor,Cells, Vertebrate Photoreceptor,Cones and Rods,Photoreceptor Cell, Retinal,Photoreceptor Cell, Vertebrate,Photoreceptor Cells, Retinal,Photoreceptor, Retinal,Photoreceptor, Vertebrate,Retinal Photoreceptor,Retinal Photoreceptor Cell,Vertebrate Photoreceptor,Vertebrate Photoreceptor Cell