Retinal Rod Photoreceptor Cells
Photoreceptor Cells
Rod Cell Outer Segment
Rhodopsin
Transducin
Photoreceptor Cells, Vertebrate
Retinal Cone Photoreceptor Cells
Retina
Eye Proteins
Retinal Degeneration
Rod Opsins
Photoreceptor Cells, Invertebrate
Arrestin
G-Protein-Coupled Receptor Kinase 1
3',5'-Cyclic-GMP Phosphodiesterases
Cattle
Vision, Ocular
Retinal Pigments
Cyclic Nucleotide Phosphodiesterases, Type 6
Dark Adaptation
Ambystoma
Recoverin
Retinitis Pigmentosa
Bufo marinus
Cyclic GMP
Retinal Bipolar Cells
Occupancy of the chromophore binding site of opsin activates visual transduction in rod photoreceptors. (1/1358)
The retinal analogue beta-ionone was used to investigate possible physiological effects of the noncovalent interaction between rod opsin and its chromophore 11-cis retinal. Isolated salamander rod photoreceptors were exposed to bright light that bleached a significant fraction of their pigment, were allowed to recover to a steady state, and then were exposed to beta-ionone. Our experiments show that in bleach-adapted rods beta-ionone causes a decrease in light sensitivity and dark current and an acceleration of the dim flash photoresponse and the rate constants of guanylyl cyclase and cGMP phosphodiesterase. Together, these observations indicate that in bleach-adapted rods beta-ionone activates phototransduction in the dark. Control experiments showed no effect of beta-ionone in either fully dark-adapted or background light-adapted cells, indicating direct interaction of beta-ionone with the free opsin produced by bleaching. We speculate that beta-ionone binds specifically in the chromophore pocket of opsin to produce a complex that is more catalytically potent than free opsin alone. We hypothesize that a similar reaction may occur in the intact retina during pigment regeneration. We propose a model of rod pigment regeneration in which binding of 11-cis retinal to opsin leads to activation of the complex accompanied by a decrease in light sensitivity. The subsequent covalent attachment of retinal to opsin completely inactivates opsin and leads to the recovery of sensitivity. Our findings resolve the conflict between biochemical and physiological data concerning the effect of the occupancy of the chromophore binding site on the catalytic potency of opsin. We show that binding of beta-ionone to rod opsin produces effects opposite to its previously described effects on cone opsin. We propose that this distinction is due to a fundamental difference in the interaction of rod and cone opsins with retinal, which may have implications for the different physiology of the two types of photoreceptors. (+info)Properties and functional roles of hyperpolarization-gated currents in guinea-pig retinal rods. (2/1358)
1. The inward rectification induced by membrane hyperpolarization was studied in adult guinea-pig rods by the perforated-patch-clamp technique. 2. CsCl blocked the rectification observed in both voltage- and current-clamp recordings at voltages negative to -60 mV, while BaCl2 blocked the inward relaxation observed at voltages positive to -60 mV. The current activated at -90 mV had a low selectivity between sodium and potassium and reversed at -31.0 mV. 3. These observations suggest that two inward rectifiers are present in guinea-pig rods: a hyperpolarization-activated (Ih) and a hyperpolarization-deactivated (Ikx) current. The functional roles of Ih and Ikx were evaluated by stimulating rods with currents sinusoidally modulated in time. 4. Rods behave like bandpass amplifiers, with a peak amplification of 1.5 at about 2 Hz. For hyperpolarizations that mainly gate Ikx, amplification and phase shifts are fully accounted for by a rod membrane analogue model that includes an inductance. For hyperpolarizations that also gate Ih, a harmonic distortion became apparent. 5. Bandpass filtering and amplification of rod signals, associated with Ih and Ikx gating by membrane hyperpolarization, are strategically located to extend, beyond the limits imposed by the slow phototransductive cascade, the temporal resolution of signals spreading to the rod synapse. (+info)Formate-induced inhibition of photoreceptor function in methanol intoxication. (3/1358)
Formic acid is the toxic metabolite responsible for the retinal and optic nerve toxicity produced in methanol intoxication. Previous studies in our laboratory have documented formate-induced retinal dysfunction and histopathology in a rodent model of methanol intoxication. The present studies define the time and concentration dependence of formate-induced retinal toxicity in methanol-intoxicated rats. Retinal function was assessed 24, 48, and 72 h after the initial dose of methanol by flicker electroretinographic measurements. Retinal histopathology was assessed at the same time intervals. Rod- and cone-mediated electroretinogram (ERG) responses were attenuated in a formate concentration- and time-dependent manner, and both retinal sensitivity and maximal responsiveness to light were diminished. Attenuation of UV-cone-mediated responses was temporally delayed in comparison to the functional deficits observed in the 15 Hz/510 nm responses, which have a rod-mediated component and occurred at significantly higher formate concentrations. Both 15 Hz/510 nm and UV-cone-mediated ERG responses were undetectable by 72 h; however, if light intensity was increased, a retinal ERG response could be recorded, indicating that photoreceptor function was profoundly attenuated, but not abolished, under these intoxication conditions. Functional changes preceded structural alterations. Histopathological changes were most pronounced in the outer retina with evidence of inner segment swelling, photoreceptor mitochondrial disruption, and the appearance of fragmented photoreceptor nuclei in the outer nuclear layer. The nature of both the functional and structural alterations observed are consistent with formate-induced inhibition of mitochondrial energy production, resulting in photoreceptor dysfunction and pathology. (+info)Sensitivity and kinetics of mouse rod flash responses determined in vivo from paired-flash electroretinograms. (4/1358)
1. Electroretinograms (ERGs) were recorded corneally from C57BL/6J mice using a paired-flash procedure in which a brief test flash at time zero was followed at time tprobe by a bright probe flash of fixed strength, and in which the probe response amplitude was determined at time t = tprobe + 6 ms. Probe responses obtained in a series of paired-flash trials were analysed to derive A(t), a family of amplitudes that putatively represents the massed response of the rod photoreceptors to the test flash. A central aim was to obtain a mathematical description of the normalized derived response A(t)/Amo as a function of Itest, the test flash strength. 2. With fixed tprobe (80 <= tprobe <= 1200 ms), A(t)/Amo was described by the saturating exponential function [1 - exp(-ktItest)], where kt is a time-dependent sensitivity parameter. For t = 86 ms, a time near the peak of A(t), k86 was 7.0 +/- 1.2 (scotopic cd s m-2)-1 (mean +/- s. d.; n = 4). 3. A(t)/Amo data were analysed in relation to the equation below, a time-generalized form of the above exponential function in which (k86Itest) is replaced by the product [k86Itestu(t)], and where u(t) is independent of the test flash strength. The function u(t) was modelled as the product of a scaling factor gamma, an activation term 1 - exp[-alpha(t - td)2]), and a decay term exp(-t/tauomega): A(t)/Amo = 1 - exp[-k86Itestu(t)]; u(t) = gamma(1 - exp[-alpha(t - td)2](exp(-t/tauomega) where td is a brief delay, tauomega is an exponential time constant, and alpha characterizes the acceleration of the activation term. For Itest up to approximately 2.57 scotopic cd s m-2, the overall time course of A(t) was well described by the above equation with gamma = 2.21, td = 3.1 ms, tauomega = 132 ms and alpha = 2.32 x 10-4 ms-2. An approximate halving of alpha improved the fit of the above equation to ERG a-wave and A(t)/Amo data obtained at t about 0-20 ms. 4. Kinetic and sensitivity properties of A(t) suggest that it approximates the in vivo massed photocurrent response of the rods to a test flash, and imply that u(t) in the above equation is the approximate kinetic description of a unit, i.e. single photon, response. (+info)Abnormal photoresponses and light-induced apoptosis in rods lacking rhodopsin kinase. (5/1358)
Phosphorylation is thought to be an essential first step in the prompt deactivation of photoexcited rhodopsin. In vitro, the phosphorylation can be catalyzed either by rhodopsin kinase (RK) or by protein kinase C (PKC). To investigate the specific role of RK, we inactivated both alleles of the RK gene in mice. This eliminated the light-dependent phosphorylation of rhodopsin and caused the single-photon response to become larger and longer lasting than normal. These results demonstrate that RK is required for normal rhodopsin deactivation. When the photon responses of RK-/- rods did finally turn off, they did so abruptly and stochastically, revealing a first-order backup mechanism for rhodopsin deactivation. The rod outer segments of RK-/- mice raised in 12-hr cyclic illumination were 50% shorter than those of normal (RK+/+) rods or rods from RK-/- mice raised in constant darkness. One day of constant light caused the rods in the RK-/- mouse retina to undergo apoptotic degeneration. Mice lacking RK provide a valuable model for the study of Oguchi disease, a human RK deficiency that causes congenital stationary night blindness. (+info)Reciprocity between light intensity and rhodopsin concentration across the rat retina. (6/1358)
1. If a purpose of photostasis - absorption of a constant number of photons by the retina, regardless of incident light levels - is to maintain rods at saturation during the light period, then in retinal regions where light intensity is low, rhodopsin concentration should be high, and vice versa. 2. Our ocular transmission photometric measurements revealed that the distribution of light intensity across the rat retina was not as simple as had been thought and, furthermore, that the local concentration of rhodopsin had a high negative correlation with the light intensity. 3. The reciprocity between these two parameters leads to nearly uniform rates of photon absorption in rods across the retina. (+info)Regulation of mammalian circadian behavior by non-rod, non-cone, ocular photoreceptors. (7/1358)
Circadian rhythms of mammals are entrained by light to follow the daily solar cycle (photoentrainment). To determine whether retinal rods and cones are required for this response, the effects of light on the regulation of circadian wheel-running behavior were examined in mice lacking these photoreceptors. Mice without cones (cl) or without both rods and cones (rdta/cl) showed unattenuated phase-shifting responses to light. Removal of the eyes abolishes this behavior. Thus, neither rods nor cones are required for photoentrainment, and the murine eye contains additional photoreceptors that regulate the circadian clock. (+info)Is the rod visual field temporally homogeneous? (8/1358)
Cone vision has been shown to be temporally inhomogeneous across the visual field. In the periphery, contrast sensitivity is lower for low temporal frequencies and higher for high temporal frequencies. Here we ask a similar question for rod vision at mesopic luminances. Isolation is obtained by testing a well documented rod monochromat. We show that the rod visual field exhibits only a modest degree of temporal inhomogeneity. (+info)Retinal rod photoreceptor cells are specialized neurons in the retina of the eye that are primarily responsible for vision in low light conditions. They contain a light-sensitive pigment called rhodopsin, which undergoes a chemical change when struck by a single photon of light. This triggers a cascade of biochemical reactions that ultimately leads to the generation of electrical signals, which are then transmitted to the brain via the optic nerve.
Rod cells do not provide color vision or fine detail, but they allow us to detect motion and see in dim light. They are more sensitive to light than cone cells, which are responsible for color vision and detailed sight in bright light conditions. Rod cells are concentrated at the outer edges of the retina, forming a crescent-shaped region called the peripheral retina, with fewer rod cells located in the central region of the retina known as the fovea.
Photoreceptor cells are specialized neurons in the retina of the eye that convert light into electrical signals. These cells consist of two types: rods and cones. Rods are responsible for vision at low light levels and provide black-and-white, peripheral, and motion sensitivity. Cones are active at higher light levels and are capable of color discrimination and fine detail vision. Both types of photoreceptor cells contain light-sensitive pigments that undergo chemical changes when exposed to light, triggering a series of electrical signals that ultimately reach the brain and contribute to visual perception.
A rod cell outer segment is a specialized structure in the retina of the eye that is responsible for photoreception, or the conversion of light into electrical signals. Rod cells are one of the two types of photoreceptor cells in the retina, with the other type being cone cells. Rod cells are more sensitive to light than cone cells and are responsible for low-light vision and peripheral vision.
The outer segment of a rod cell is a long, thin structure that contains stacks of discs filled with the visual pigment rhodopsin. When light hits the rhodopsin molecules in the discs, it causes a chemical reaction that leads to the activation of a signaling pathway within the rod cell. This ultimately results in the generation of an electrical signal that is transmitted to the brain via the optic nerve.
The outer segment of a rod cell is constantly being regenerated and broken down through a process called shedding and renewal. The tips of the outer segments are shed and phagocytosed by cells called retinal pigment epithelial (RPE) cells, which help to maintain the health and function of the rod cells.
Rhodopsin, also known as visual purple, is a light-sensitive pigment found in the rods of the vertebrate retina. It is a complex protein molecule made up of two major components: an opsin protein and retinal, a form of vitamin A. When light hits the retinal in rhodopsin, it changes shape, which initiates a series of chemical reactions leading to the activation of the visual pathway and ultimately results in vision. This process is known as phototransduction. Rhodopsin plays a crucial role in low-light vision or scotopic vision.
Transducin is a G protein found in the rod cells of the retina and plays a crucial role in the visual signal transduction pathway. It is responsible for converting the light-induced isomerization of rhodopsin into a biochemical signal, which ultimately leads to the activation of downstream effectors and the generation of a neural response.
Transducin has three subunits: alpha (Tα), beta (Tβ), and gamma (Tγ). When light activates rhodopsin, it interacts with the Tα subunit, causing it to exchange GDP for GTP and dissociate from the Tβγ complex. The activated Tα then interacts with a downstream effector called phosphodiesterase (PDE), which leads to the hydrolysis of cGMP and the closure of cGMP-gated ion channels in the plasma membrane. This results in the hyperpolarization of the rod cell, which is the initial step in the visual signal transduction pathway.
Overall, transducin is a key player in the conversion of light energy into neural signals, allowing us to see and perceive our visual world.
Photoreceptor cells in vertebrates are specialized types of neurons located in the retina of the eye that are responsible for converting light stimuli into electrical signals. These cells are primarily responsible for the initial process of vision and have two main types: rods and cones.
Rods are more numerous and are responsible for low-light vision or scotopic vision, enabling us to see in dimly lit conditions. They do not contribute to color vision but provide information about the shape and movement of objects.
Cones, on the other hand, are less numerous and are responsible for color vision and high-acuity vision or photopic vision. There are three types of cones, each sensitive to different wavelengths of light: short (S), medium (M), and long (L) wavelengths, which correspond to blue, green, and red, respectively. The combination of signals from these three types of cones allows us to perceive a wide range of colors.
Both rods and cones contain photopigments that consist of a protein called opsin and a light-sensitive chromophore called retinal. When light hits the photopigment, it triggers a series of chemical reactions that ultimately lead to the generation of an electrical signal that is transmitted to the brain via the optic nerve. This process enables us to see and perceive our visual world.
Retinal cone photoreceptor cells are specialized neurons located in the retina of the eye, responsible for visual phototransduction and color vision. They are one of the two types of photoreceptors, with the other being rods, which are more sensitive to low light levels. Cones are primarily responsible for high-acuity, color vision during daylight or bright-light conditions.
There are three types of cone cells, each containing different photopigments that absorb light at distinct wavelengths: short (S), medium (M), and long (L) wavelengths, which correspond to blue, green, and red light, respectively. The combination of signals from these three types of cones allows the human visual system to perceive a wide range of colors and discriminate between them. Cones are densely packed in the central region of the retina, known as the fovea, which provides the highest visual acuity.
The retina is the innermost, light-sensitive layer of tissue in the eye of many vertebrates and some cephalopods. It receives light that has been focused by the cornea and lens, converts it into neural signals, and sends these to the brain via the optic nerve. The retina contains several types of photoreceptor cells including rods (which handle vision in low light) and cones (which are active in bright light and are capable of color vision).
In medical terms, any pathological changes or diseases affecting the retinal structure and function can lead to visual impairment or blindness. Examples include age-related macular degeneration, diabetic retinopathy, retinal detachment, and retinitis pigmentosa among others.
Eye proteins, also known as ocular proteins, are specific proteins that are found within the eye and play crucial roles in maintaining proper eye function and health. These proteins can be found in various parts of the eye, including the cornea, iris, lens, retina, and other structures. They perform a wide range of functions, such as:
1. Structural support: Proteins like collagen and elastin provide strength and flexibility to the eye's tissues, enabling them to maintain their shape and withstand mechanical stress.
2. Light absorption and transmission: Proteins like opsins and crystallins are involved in capturing and transmitting light signals within the eye, which is essential for vision.
3. Protection against damage: Some eye proteins, such as antioxidant enzymes and heat shock proteins, help protect the eye from oxidative stress, UV radiation, and other environmental factors that can cause damage.
4. Regulation of eye growth and development: Various growth factors and signaling molecules, which are protein-based, contribute to the proper growth, differentiation, and maintenance of eye tissues during embryonic development and throughout adulthood.
5. Immune defense: Proteins involved in the immune response, such as complement components and immunoglobulins, help protect the eye from infection and inflammation.
6. Maintenance of transparency: Crystallin proteins in the lens maintain its transparency, allowing light to pass through unobstructed for clear vision.
7. Neuroprotection: Certain eye proteins, like brain-derived neurotrophic factor (BDNF), support the survival and function of neurons within the retina, helping to preserve vision.
Dysfunction or damage to these eye proteins can contribute to various eye disorders and diseases, such as cataracts, age-related macular degeneration, glaucoma, diabetic retinopathy, and others.
Retinal degeneration is a broad term that refers to the progressive loss of photoreceptor cells (rods and cones) in the retina, which are responsible for converting light into electrical signals that are sent to the brain. This process can lead to vision loss or blindness. There are many different types of retinal degeneration, including age-related macular degeneration, retinitis pigmentosa, and Stargardt's disease, among others. These conditions can have varying causes, such as genetic mutations, environmental factors, or a combination of both. Treatment options vary depending on the specific type and progression of the condition.
Rhodopsin, also known as visual purple, is a light-sensitive protein found in the rods of the eye's retina. It is a type of opsin, a class of proteins that are activated by light and play a crucial role in vision. Rhodopsin is composed of two parts: an apoprotein called opsin and a chromophore called 11-cis-retinal. When light hits the retina, it changes the shape of the 11-cis-retinal, which in turn activates the rhodopsin protein. This activation triggers a series of chemical reactions that ultimately lead to the transmission of a visual signal to the brain. Rhodopsin is highly sensitive to light and allows for vision in low-light conditions.
In the context of medical terminology, "light" doesn't have a specific or standardized definition on its own. However, it can be used in various medical terms and phrases. For example, it could refer to:
1. Visible light: The range of electromagnetic radiation that can be detected by the human eye, typically between wavelengths of 400-700 nanometers. This is relevant in fields such as ophthalmology and optometry.
2. Therapeutic use of light: In some therapies, light is used to treat certain conditions. An example is phototherapy, which uses various wavelengths of ultraviolet (UV) or visible light for conditions like newborn jaundice, skin disorders, or seasonal affective disorder.
3. Light anesthesia: A state of reduced consciousness in which the patient remains responsive to verbal commands and physical stimulation. This is different from general anesthesia where the patient is completely unconscious.
4. Pain relief using light: Certain devices like transcutaneous electrical nerve stimulation (TENS) units have a 'light' setting, indicating lower intensity or frequency of electrical impulses used for pain management.
Without more context, it's hard to provide a precise medical definition of 'light'.
Photoreceptor cells in invertebrates are specialized sensory neurons that convert light stimuli into electrical signals. These cells are primarily responsible for the ability of many invertebrates to detect and respond to light, enabling behaviors such as phototaxis (movement towards or away from light) and vision.
Invertebrate photoreceptor cells typically contain light-sensitive pigments that absorb light at specific wavelengths. The most common type of photopigment is rhodopsin, which consists of a protein called opsin and a chromophore called retinal. When light hits the photopigment, it changes the conformation of the chromophore, triggering a cascade of molecular events that ultimately leads to the generation of an electrical signal.
Invertebrate photoreceptor cells can be found in various locations throughout the body, depending on their function. For example, simple eyespots containing a few photoreceptor cells may be scattered over the surface of the body in some species, while more complex eyes with hundreds or thousands of photoreceptors may be present in other groups. In addition to their role in vision, photoreceptor cells can also serve as sensory organs for regulating circadian rhythms, detecting changes in light intensity, and mediating social behaviors.
Arrestin is a type of protein that plays a crucial role in regulating the signaling of G protein-coupled receptors (GPCRs) in cells. These receptors are involved in various cellular responses to hormones, neurotransmitters, and other signaling molecules.
When a signaling molecule binds to a GPCR, it activates the receptor and triggers a cascade of intracellular events, including the activation of G proteins. Arrestin binds to the activated GPCR and prevents further interaction with G proteins, effectively turning off the signal.
There are two main types of arrestins: visual arrestin (or rod arrestin) and non-visual arrestins (which include β-arrestin1 and β-arrestin2). Visual arrestin is primarily found in the retina and plays a role in regulating the light-sensitive proteins rhodopsin and cone opsin. Non-visual arrestins, on the other hand, are expressed throughout the body and regulate various GPCRs involved in diverse physiological processes such as cell growth, differentiation, and migration.
By modulating GPCR signaling, arrestins help maintain proper cellular function and prevent overactivation of signaling pathways that could lead to disease. Dysregulation of arrestin function has been implicated in various pathologies, including cancer, cardiovascular diseases, and neurological disorders.
G-Protein-Coupled Receptor Kinase 1 (GRK1) is a serine/threonine kinase that specifically phosphorylates and desensitizes G-protein-coupled receptors (GPCRs) upon agonist activation. GRK1 plays a crucial role in the regulation of GPCR signaling, which is involved in various physiological processes, including sensory perception, neurotransmission, and hormonal regulation.
GRK1 is primarily expressed in the retina and testis, where it regulates the activity of rhodopsin and β-adrenergic receptors, respectively. The kinase activity of GRK1 leads to the recruitment of arrestin proteins, which uncouple the receptor from its G protein, thereby terminating the signaling response. Additionally, GRK1-mediated phosphorylation creates binding sites for β-arrestins, leading to receptor internalization and subsequent degradation or recycling.
Mutations in GRK1 have been associated with various diseases, including retinitis pigmentosa, a genetic disorder that causes progressive vision loss. Therefore, understanding the function and regulation of GRK1 is essential for developing therapeutic strategies targeting GPCR-mediated diseases.
3',5'-Cyclic guanosine monophosphate (cGMP) phosphodiesterases are a group of enzymes that play a role in regulating the levels of cGMP, an important intracellular signaling molecule involved in various biological processes. These enzymes catalyze the hydrolysis of cGMP to 5'-GMP, thereby terminating cGMP-mediated signals within cells.
There are several isoforms of cGMP phosphodiesterases, which differ in their regulatory properties, substrate specificity, and cellular distribution. These enzymes can be activated or inhibited by various factors, including drugs, hormones, and neurotransmitters, and play a crucial role in modulating the activity of cGMP-dependent signaling pathways in different tissues and organs.
Dysregulation of cGMP phosphodiesterase activity has been implicated in various diseases, including cardiovascular disorders, pulmonary hypertension, neurodegenerative diseases, and cancer. Therefore, these enzymes are considered important targets for the development of novel therapeutic strategies for the treatment of these conditions.
"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.
Ocular vision refers to the ability to process and interpret visual information that is received by the eyes. This includes the ability to see clearly and make sense of the shapes, colors, and movements of objects in the environment. The ocular system, which includes the eye and related structures such as the optic nerve and visual cortex of the brain, works together to enable vision.
There are several components of ocular vision, including:
* Visual acuity: the clarity or sharpness of vision
* Field of vision: the extent of the visual world that is visible at any given moment
* Color vision: the ability to distinguish different colors
* Depth perception: the ability to judge the distance of objects in three-dimensional space
* Contrast sensitivity: the ability to distinguish an object from its background based on differences in contrast
Disorders of ocular vision can include refractive errors such as nearsightedness or farsightedness, as well as more serious conditions such as cataracts, glaucoma, and macular degeneration. These conditions can affect one or more aspects of ocular vision and may require medical treatment to prevent further vision loss.
Electroretinography (ERG) is a medical test used to evaluate the functioning of the retina, which is the light-sensitive tissue located at the back of the eye. The test measures the electrical responses of the retina to light stimulation.
During the procedure, a special contact lens or electrode is placed on the surface of the eye to record the electrical activity generated by the retina's light-sensitive cells (rods and cones) and other cells in the retina. The test typically involves presenting different levels of flashes of light to the eye while the electrical responses are recorded.
The resulting ERG waveform provides information about the overall health and function of the retina, including the condition of the photoreceptors, the integrity of the inner retinal layers, and the health of the retinal ganglion cells. This test is often used to diagnose and monitor various retinal disorders, such as retinitis pigmentosa, macular degeneration, and diabetic retinopathy.
Retinal pigments refer to the light-sensitive chemicals found in the retina, specifically within the photoreceptor cells called rods and cones. The main types of retinal pigments are rhodopsin (also known as visual purple) in rods and iodopsins in cones. These pigments play a crucial role in the process of vision by absorbing light and initiating a series of chemical reactions that ultimately trigger nerve impulses, which are then transmitted to the brain and interpreted as visual images. Rhodopsin is more sensitive to lower light levels and is responsible for night vision, while iodopsins are sensitive to specific wavelengths of light and contribute to color vision.
Cyclic nucleotide phosphodiesterases (PDEs) are a family of enzymes that play a crucial role in regulating intracellular levels of cyclic nucleotides, which are important second messengers in various cellular signaling pathways. Among the different types of PDEs, type 6 (PDE6) is specifically expressed in the photoreceptor cells of the retina and is involved in the visual signal transduction cascade.
PDE6 is composed of two catalytic subunits, PDE6α and PDE6β, which are arranged in a heterodimeric complex. These subunits have distinct roles in the enzyme's activity: PDE6α contains the catalytic site that hydrolyzes cyclic guanosine monophosphate (cGMP) to GMP, while PDE6β regulates the activity of PDE6α through its inhibitory γ subunit.
In the visual signal transduction pathway, light stimulation leads to the activation of rhodopsin, which triggers a cascade of events that ultimately results in the hydrolysis of cGMP by PDE6. This reduction in cGMP levels causes the closure of cyclic nucleotide-gated channels in the plasma membrane, leading to hyperpolarization of the photoreceptor cells and the transmission of visual signals to the brain.
Defects in PDE6 have been implicated in various retinal disorders, including congenital stationary night blindness, retinitis pigmentosa, and age-related macular degeneration. Therefore, understanding the structure and function of PDE6 is essential for developing novel therapeutic strategies to treat these vision-threatening diseases.
Dark adaptation is the process by which the eyes adjust to low levels of light. This process allows the eyes to become more sensitive to light and see better in the dark. It involves the dilation of the pupils, as well as chemical changes in the rods and cones (photoreceptor cells) of the retina. These changes allow the eye to detect even small amounts of light and improve visual acuity in low-light conditions. Dark adaptation typically takes several minutes to occur fully, but can be faster or slower depending on various factors such as age, prior exposure to light, and certain medical conditions. It is an important process for maintaining good vision in a variety of lighting conditions.
"Ambystoma" is a genus of salamanders, also known as the mole salamanders. These amphibians are characterized by their fossorial (burrowing) habits and typically have four limbs, a tail, and moist skin. They are found primarily in North America, with a few species in Asia and Europe. Some well-known members of this genus include the axolotl (A. mexicanum), which is famous for its ability to regenerate lost body parts, and the spotted salamander (A. maculatum). The name "Ambystoma" comes from the Greek words "amblys," meaning blunt, and "stoma," meaning mouth, in reference to the wide, blunt snout of these animals.
Recoverin is a protein found in the retina of the eye that plays a role in protecting photoreceptor cells from light-induced damage. It is a member of the neuronal calcium sensor family and functions as a calmodulin-binding protein, which means it can bind to calcium ions and regulate various cellular processes.
Recoverin is particularly important for the regulation of visual transduction, the process by which light is converted into electrical signals in the eye. When exposed to light, photoreceptor cells release calcium ions, which then bind to recoverin and cause it to change shape. This shape change allows recoverin to inhibit a key enzyme involved in the visual transduction cascade, helping to prevent excessive signaling and protect the photoreceptor cells from damage.
Mutations in the gene that encodes recoverin have been associated with certain inherited eye diseases, such as congenital stationary night blindness and retinitis pigmentosa. These mutations can disrupt the normal function of recoverin and lead to progressive vision loss.
Retinitis pigmentosa (RP) is a group of rare, genetic disorders that involve a breakdown and loss of cells in the retina - a light-sensitive tissue located at the back of the eye. The retina converts light into electrical signals which are then sent to the brain and interpreted as visual images.
In RP, the cells that detect light (rods and cones) degenerate more slowly than other cells in the retina, leading to a progressive loss of vision. Symptoms typically begin in childhood with night blindness (difficulty seeing in low light), followed by a gradual narrowing of the visual field (tunnel vision). Over time, this can lead to significant vision loss and even blindness.
The condition is usually inherited and there are several different genes that have been associated with RP. The diagnosis is typically made based on a combination of genetic testing, family history, and clinical examination. Currently, there is no cure for RP, but researchers are actively working to develop new treatments that may help slow or stop the progression of the disease.
Light signal transduction is a biological process that refers to the way in which cells convert light signals into chemical or electrical responses. This process typically involves several components, including a light-sensitive receptor (such as a photopigment), a signaling molecule (like a G-protein or calcium ion), and an effector protein that triggers a downstream response.
In the visual system, for example, light enters the eye and activates photoreceptor cells in the retina. These cells contain a light-sensitive pigment called rhodopsin, which undergoes a chemical change when struck by a photon of light. This change triggers a cascade of signaling events that ultimately lead to the transmission of visual information to the brain.
Light signal transduction is also involved in other biological processes, such as the regulation of circadian rhythms and the synthesis of vitamin D. In these cases, specialized cells contain light-sensitive receptors that allow them to detect changes in ambient light levels and adjust their physiology accordingly.
Overall, light signal transduction is a critical mechanism by which organisms are able to sense and respond to their environment.
'Bufo marinus' is the scientific name for a species of toad commonly known as the Cane Toad or Giant Toad. This toad is native to Central and South America, but has been introduced to various parts of the world including Florida, Australia, and several Pacific islands. The toad produces a toxic secretion from glands on its back and neck, which can be harmful or fatal if ingested by pets or humans.
Cyclic guanosine monophosphate (cGMP) is a important second messenger molecule that plays a crucial role in various biological processes within the human body. It is synthesized from guanosine triphosphate (GTP) by the enzyme guanylyl cyclase.
Cyclic GMP is involved in regulating diverse physiological functions, such as smooth muscle relaxation, cardiovascular function, and neurotransmission. It also plays a role in modulating immune responses and cellular growth and differentiation.
In the medical field, changes in cGMP levels or dysregulation of cGMP-dependent pathways have been implicated in various disease states, including pulmonary hypertension, heart failure, erectile dysfunction, and glaucoma. Therefore, pharmacological agents that target cGMP signaling are being developed as potential therapeutic options for these conditions.
Retinal bipolar cells are a type of neuron located in the inner nuclear layer of the retina, an light-sensitive tissue that lines the interior of the eye. These cells play a crucial role in the visual system by transmitting visual signals from photoreceptors (rods and cones) to ganglion cells, which then relay this information to the brain via the optic nerve.
Bipolar cells have two processes or "arms" that connect to either photoreceptors or ganglion cells: one process receives input from photoreceptors and the other transmits output to ganglion cells. They are called "bipolar" because of this dual connection. These cells can be classified into different types based on their morphology, neurotransmitter usage, and synaptic connections with photoreceptors and ganglion cells.
There are two primary types of retinal bipolar cells: rod bipolar cells and cone bipolar cells. Rod bipolar cells mainly transmit signals from rod photoreceptors, which are responsible for low-light vision, while cone bipolar cells connect to cone photoreceptors that handle color vision and high visual acuity in bright light conditions.
Retinal bipolar cells help process and encode visual information based on contrast, spatial patterns, and temporal changes in light intensity. Their output contributes significantly to the formation of visual perceptions such as brightness, contrast, and motion detection. Dysfunction or damage to retinal bipolar cells can lead to various visual impairments and diseases, including some forms of vision loss.
I am not aware of a medical definition for the term "darkness." In general, darkness refers to the absence of light. It is not a term that is commonly used in the medical field, and it does not have a specific clinical meaning. If you have a question about a specific medical term or concept, I would be happy to try to help you understand it.
Cyclic nucleotide-gated (CNG) channels are a type of ion channel found in the membranes of certain cells, particularly in the sensory neurons of the visual and olfactory systems. They are called cyclic nucleotide-gated because they can be activated or regulated by the binding of cyclic nucleotides, such as cyclic adenosine monophosphate (cAMP) or cyclic guanosine monophosphate (cGMP), to the intracellular domain of the channel.
CNG channels are permeable to cations, including sodium (Na+) and calcium (Ca2+) ions, and their activation allows these ions to flow into the cell. This influx of cations can trigger a variety of cellular responses, such as the initiation of visual or olfactory signaling pathways.
CNG channels are composed of four subunits that form a functional channel. Each subunit has a cyclic nucleotide-binding domain (CNBD) in its intracellular region, which can bind to cyclic nucleotides and regulate the opening and closing of the channel. The CNBD is connected to the pore-forming region of the channel by a flexible linker, allowing for conformational changes in the CNBD to be transmitted to the pore and modulate ion conductance.
CNG channels play important roles in various physiological processes, including sensory perception, neurotransmission, and cellular signaling. Dysfunction of CNG channels has been implicated in several human diseases, such as retinitis pigmentosa, congenital stationary night blindness, and cystic fibrosis.
Photoreceptor cell
Adaptation (eye)
King-Wai Yau
PDE6B
SARM1
Ignacio Provencio
Retinal
ABCA4
Electroretinography
Emixustat
AII amacrine cells
Ophthalmology
Retinal regeneration
Ursodoxicoltaurine
Retinal degeneration (rhodopsin mutation)
CRX (gene)
RPE65
Denis Baylor
Usher syndrome
Müller glia
Retinal ganglion cell
Retinal precursor cells
Amacrine cell
Rod cell
Palisade (pathology)
Progressive retinal atrophy
Retinal haemorrhage
Neuroscience of rhythm
RP1
Visual system
Intrinsically photosensitive retinal ganglion cell
Neurofascin Is a Novel Component of Rod Photoreceptor Synapses in the Outer Retina
Nano-scale resolution of native retinal rod disk membranes reveals differences in lipid composition
Adaptation (eye) - Wikipedia
US20120157377A1 - Methods to enhance night vision and treatment of night blindness - Google Patents
Six teams seek to identify biological factors that influence neural regeneration | National Institutes of Health (NIH)
NEI Office of Regenerative Medicine: Vision Innovation Seminars | National Eye Institute
Characterization of macular structure and function in two swedish families with genetically identified autosomal dominant...
Publications - Bader Lab @ The University of Toronto
NIOSHTIC-2 Search Results - Basic View
Retinal Development, Genetics and Therapy Section | National Eye Institute
Eye Problems That Come with Aging
John G. Flannery | Molecular and Cell Biology
Activation of Rod Input in a Model of Retinal Degeneration Reverses Retinal Remodeling
and Induces Formation of...
TICA Science Newsletter - Volume 2 - December 2018
Historic Timeline of NYEE | New York Eye & Ear
Blue light-induced retinal lesions, intraretinal vascular leakage and edema formation in the all-cone mouse retina | Cell Death...
MVRF Supported Study At Penn Discovers Same Cell Death Pathway In 3 Forms Of Blindness - Macula Vision Research Foundation
Comprehensive analysis of photoreceptor gene expression and the identification of candidate retinal disease genes<...
Engineered molecular device may restore vision lost to retinal diseases | Chicago Medicine
Plus it
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Degeneration27
- Many common eye diseases, including age-related macular degeneration, glaucoma and diabetic retinopathy, put these cells at risk. (nih.gov)
- Dr. Bo Chen's research focuses on mechanistic and therapeutic studies of retinal degenerative diseases caused by loss of photoreceptors or retinal ganglion cells, such as age-related macular degeneration, retinitis pigmentosa, and glaucoma. (nih.gov)
- The mother, with a de novo mutation in the RHO (p.R135W) gene, had a normal ffERG, and her retinal degeneration was detected merely with the reduced mfERG. (lu.se)
- Dysfunction or loss of photoreceptors is the primary cause of vision impairment in almost all cases of retinal and macular degeneration. (nih.gov)
- Inherited forms of retinal degeneration, which afflict 1 in 3000 people worldwide, arise primarily from mutations in transcripts expressed in rod and cone photoreceptors and retinal pigment epithelial cells. (berkeley.edu)
- Our laboratory focuses on understanding the genetic and mechanistic underpinning of photoreceptor degeneration, and developing rational therapies for these blinding conditions. (berkeley.edu)
- Gene therapy has great potential for treating retinal diseases including glaucoma, age-related macular degeneration, and inherited photoreceptor diseases. (berkeley.edu)
- The retina is susceptible to a number of blinding diseases, such as age-related macular degeneration, diabetic retinopathy and other inherited retinal degenerations. (berkeley.edu)
- In addition, gene identification in patients permits us to identify naturally occurring animal models or create new transgenic or knockout animal models with retinal degeneration due to defects in the gene homologs. (berkeley.edu)
- In particular, we have the examined retinal degeneration in the naturally arising rd mouse strains (defects in the b-subunit of phosphodiesterase). (berkeley.edu)
- These animal models are the subject of study to determine the pathophysiological mechanisms whereby these gene defects lead to photoreceptor degeneration and hopefully will lead to pilot studies of novel therapies for retinal degeneration. (berkeley.edu)
- In previous work, we have demonstrated significant slowing of photoreceptor degeneration in several animal models following gene transfer of neurotrophic agents. (berkeley.edu)
- Activation of Rod Input in a Model of Retinal Degeneration Reverses Retinal Remodeling and Induces Formation of Functional Synapses and Recovery of Visual Signaling in the Adult Retina. (duke.edu)
- Retinas from these mice undergo stereotypic retinal remodeling as a consequence of rod malfunction and degeneration. (duke.edu)
- These findings demonstrate remarkable plasticity extending beyond the developmental period and support efforts to repair or replace defective rods in patients blinded by rod degeneration. (duke.edu)
- The acute model of light-induced retinal degeneration uses short exposure to bright white light to study photoreceptor cell death leading to loss of vision. (nature.com)
- The team examined three forms of retinal degenerative diseases, rod cone dysplasia 1 being the most severe, or earliest onset, followed by X-linked progressive retinal atrophy 2 and then early retinal degeneration. (mvrf.org)
- According to Dr. Pepperberg, success in this early work and in future studies that test the technology in animal experiments could lead to a new type of molecular therapy for macular degeneration and related photoreceptor degenerative diseases. (uic.edu)
- This disk membrane deficiency is one of the most severe among the retinal degeneration models and is comparable to rhodopsin knock-out mice that are also incapable of forming disks. (jneurosci.org)
- Dynamic in vivo quantification of rod photoreceptor degeneration using fluorescent reporter mouse models of retinitis pigmentosa. (ox.ac.uk)
- Here we describe a novel technique for the in vivo visualisation of rod photoreceptors which permits semiquantitative assessment of outer retinal degeneration, and validate this approach in two mouse models of retinitis pigmentosa (RP). (ox.ac.uk)
- These novel strains have green fluorescent rods which undergo a progressive degeneration. (ox.ac.uk)
- Focal loss of rods could be visualised and mapped in vivo with this technique following a toxic insult, with thinning of the ONL being confirmed in hypofluorescent regions by spectral domain ocular coherence tomography (OCT). Fluorescence labelling of rods permits in vivo characterisation of models of RP and may provide new insights into patterns of degeneration, or rescue effect after treatment. (ox.ac.uk)
- mGV can be used in such cases as a semiquantitative metric of ONL degeneration, and can be used to identify regional variations in photoreceptor loss. (ox.ac.uk)
- Growing evidence suggests a role for lysosome-related mechanisms in retinal degeneration. (irrf.org)
- Oxidative stress plays a key role in driving pathological events in several different ocular diseases, which lead to retinal degeneration and ultimately blindness. (mdpi.com)
- The disease leads to degeneration of retinal photoreceptor cells in dog. (genocan.eu)
Neurons9
- To study these conditions, his laboratory pursues two main strategies: neuroprotective strategy to save existing retinal neurons and neural regenerative strategy to produce new retinal neurons. (nih.gov)
- Any damage to retinal neurons can have devastating consequences, including loss of vision. (nih.gov)
- Moreover, fukutin may be involved in synaptic functions of retinal neurons through the glycosylation of α-DG. (intechopen.com)
- However, it remains unclear whether there is a cell fate switch of Math5-lineage cells in the absence of Math5 and whether MATH5 cell-autonomously regulates the differentiation of the above retinal neurons. (elsevierpure.com)
- If our rods or rod system neurons become diseased and degenerated we become night blind as happens to unfortunate people who have a disease called retinitis pigmentosa. (utah.edu)
- That is, rod photoreceptors out-number cone photoreceptors by orders of magnitude and the consequent second- and third-order neurons recruited for processing rod-driven vision outnumber the cone pathways neurons everywhere but in the central fovea. (utah.edu)
- Consequently, the present research looked into whether SHH could be changed by purmorphamine within the transdifferentiation of Mller glial cells to retinal neurons, and therefore, attempted to give a far more convenient, stabilized and effective therapy. (exposed-skin-care.net)
- The combined results indicate that glycolysis is regulated by the compartmental expression of hexokinase 2, pyruvate kinase M1, and pyruvate kinase M2 in photoreceptors, whereas the inner retinal neurons exhibit a lower capacity for glycolysis and aerobic glycolysis. (molvis.org)
- Expression of nucleoside diphosphate kinase, mitochondria-associated adenylate kinase, and several mitochondria-associated creatine kinase isozymes was highest in the outer retina, whereas expression of cytosolic adenylate kinase and brain creatine kinase was higher in the cones, horizontal cells, and amacrine cells indicating the diversity of ATP-buffering strategies among retinal neurons. (molvis.org)
Cone photoreceptor4
- The retina is a complex tissue in the back of the eye that contains the rod and cone photoreceptor cells. (berkeley.edu)
- Intrinsically photosensitive retinal ganglion cells (ipRGCs) are a subset of retinal ganglion cells that respond to light independently from rod and cone photoreceptor input. (indianactsi.org)
- Piriev N, Yamashita CK, Shih J, Farber DB: Expression of functionally active cone photoreceptor cGMP-PDE o' subunit in chinese humster ovary, 293 human embryonic kidney and Y79 retinoblastoma cells. (uclahealth.org)
- Genome editing was previously used to restore vision in mice with the genetic eye disease Leber congenital amaurosis, which affects the retinal pigment epithelium, a layer of non-neuronal cells in the eye that supports the light-sensing rod and cone photoreceptor cells. (scienceboard.net)
Photosensitive retinal gangl3
- There are currently three known types of photoreceptor cells in mammalian eyes: rods, cones, and intrinsically photosensitive retinal ganglion cells. (wikipedia.org)
- A third class of mammalian photoreceptor cell was discovered during the 1990s: the intrinsically photosensitive retinal ganglion cells. (wikipedia.org)
- We also know that these photosensitive retinal ganglion cells mediate a broad range of physiological responses to light, ranging from the regulation of circadian rhythms to pupil constriction. (ox.ac.uk)
Retinitis pigmentosa6
- The inherited retinal degenerations are typified by retinitis pigmentosa (RP), which results in blindness from destruction of photoreceptor cells, and the RPE. (berkeley.edu)
- Mutations in several genes essential for photoreceptor structure and/or function [as in Retinitis Pigmentosa (RP)], in conjunction with the fact that photoreceptors are metabolically very active makes these cells highly susceptible to damage and death. (lu.se)
- Retinitis pigmentosa is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. (nih.gov)
- However, most inherited forms of blindness, including retinitis pigmentosa, are caused by genetic defects in the photoreceptors themselves. (scienceboard.net)
- By the age of four months, the retinas of control mice with uncorrected retinitis pigmentosa were observed to be thin and lacking in rod photoreceptors. (scienceboard.net)
- However, our study provides substantial evidence for the in vivo applicability of this new genome-editing strategy and its potential in diverse research and therapeutic contexts -- in particular for inherited retinal diseases such as retinitis pigmentosa," co-author Kai Yao, Wuhan University of Science and Technology professor, said in a statement. (scienceboard.net)
Pigment13
- The membranous photoreceptor protein opsin contains a pigment molecule called retinal. (wikipedia.org)
- The adjacent retinal pigment epithelium (RPE) supports many of the retina's metabolic functions. (berkeley.edu)
- Clinical evidence for neovascularization includes retinal pigment epithelium (RPE) elevation, subretinal hemorrhage, and/or the presence of exudate. (medscape.com)
- The atrophic retinal pigment epithelium (RPE) demonstrates staining of the underlying choroidal vasculature. (medscape.com)
- The atrophic areas are easily distinguished by the hyperfluorescence of the retinal pigment epithelium (RPE) in the mid phase of the angiogram. (medscape.com)
- Note the even pigmentation of the retinal pigment epithelium and the absence of any yellow excrescences (drusen) in the fovea. (medscape.com)
- A few areas of atrophy are noted, where the retinal pigment epithelium (RPE) has lost pigmentation. (medscape.com)
- The outermost layer of the retina, the retinal pigment epithelium, is tightly attached to the choroid. (medscape.com)
- The retina, with the exception of the blood vessels coursing through it, is transparent to the examiner up to its outer layer, the retinal pigment epithelium. (medscape.com)
- The examiner sees the neurosensory retina against the background orange color of the melanin containing retinal pigment epithelium and blood-filled choroidal layer of the eye. (medscape.com)
- The neuroretina is tightly attached to the underlying retinal pigment only at the margins of the optic nerve and at the ora serrata. (medscape.com)
- There is a potential space between the neurosensory retina and the retinal pigment epithelium. (medscape.com)
- In a retinal detachment, this space fills with fluid and detaches the neurosensory retina from the underlying retinal pigment epithelium. (medscape.com)
Diseases18
- Retinal and macular diseases are a major cause of visual impairment and affect the quality of life of millions worldwide. (nih.gov)
- To date, most gene therapies have targeted monogenic recessive retinal diseases and employed viral vectors to transfer a 'normal ' copy of the mutated gene to the affected cell. (berkeley.edu)
- We are currently developing animal models of inherited retinal diseases to study the disease processes. (berkeley.edu)
- Development of effective treatments for retinal diseases. (berkeley.edu)
- Another promising strategy for dominantly inherited retinal diseases involves directly targeting the mutant mRNA product using Talens, CRISPR , and siRNA constructs. (berkeley.edu)
- We find that gene therapy has vast potential for treating and potentially curing a number of inherited photoreceptor diseases. (berkeley.edu)
- Hoping to develop a treatment that works more broadly across diseases, a Penn Vet team used canine disease models to closely examine how retinal gene activity varied during the progression of three different forms of inherited vision disease. (mvrf.org)
- Their results turned up an unexpected commonality: Early on in each of the diseases, genes involved in the same specific pathway of cell death appeared to be activated. (mvrf.org)
- These findings point to possible interventions that could curb vision loss across a variety of inherited retinal diseases. (mvrf.org)
- All of these diseases involve the death of photoreceptor cells and each is caused by a distinct genetic mutation. (mvrf.org)
- We wanted to get a better understanding of whether there are any common cell death or cell survival pathways that could be targeted in some of these diseases. (mvrf.org)
- We assumed," Aguirre said, "the diseases would be different from one another and that cells would commit suicide by their own specific pathway and that perhaps quite late they would have a common final pathway. (mvrf.org)
- Genini, Beltran and Aguirre say their results suggest that these drugs or similar ones might have a role to play in the retinal diseases they investigated and perhaps in others that their team is currently studying. (mvrf.org)
- Even after retinal diseases kill rod and cone photoreceptors - the cells of the retina that take in light - other retinal cells often remain healthy," said Dr. Pepperberg, the Searls-Schenk Professor of Ophthalmology at the UIC College of Medicine and principal investigator on the project. (uic.edu)
- Both address the overall goal of engineering devices to establish light-sensitivity and vision in patients with photoreceptor degenerative diseases. (uic.edu)
- For early-stage treatment of these degenerative retinal diseases, the rationale is to stop or delay the death of the retinal cells, which is challenging, with many patients ultimately progressing to severe visual impairment and eventually complete blindness. (lu.se)
- The researchers sought to edit the genomes of neural retinal cells, particularly unhealthy or dying photoreceptors, in order to provide evidence for the genome-editing tool's potential application in treating retinal diseases. (scienceboard.net)
- Precision genome editing agents can enable gene correction and disease rescue in inherited retinal diseases, according to University of California, Irvine. (scienceboard.net)
Lead to photore1
- What are intrinsic control mechanisms that lead to photoreceptor cell fate from retinal progenitors? (nih.gov)
Macular3
- The mfERG showed only centrally preserved macular function that correlated well with retinal thinning on OCT. The family with a mutation in the RHO (p.R135W) gene had an extreme intrafamilial variability of the phenotype, with more severe disease in the younger generations. (lu.se)
- With increasing insight into the molecular etiologies of several inherited retinal and macular dystrophies, studies from ours and many laboratories have defined several promising therapeutic strategies. (berkeley.edu)
- Little is known about the mechanisms underlying macular degenerations, mainly for the scarcity of adequate experimental models to investigate cone cell death. (nature.com)
Synapses4
- Taken together, our data suggest a new role of Nfasc in rod synapses within the mouse outer retina. (nih.gov)
- Generating appropriate synapses between photoreceptor and bipolar cells is an essential step in restoring vision through photoreceptor transplantation. (nih.gov)
- Electron microscopy of the rod bipolar cell axons in the inner plexiform layer shows that they make ribbon synapses only upon amacrine cell profiles (Fig. 8). (utah.edu)
- The electron micrograph in the top panel shows two invaginating synapses between cone and horizontal cells in the outer p. (cellimagelibrary.org)
Vertebrate3
- Most vertebrate photoreceptors are located in the retina. (wikipedia.org)
- The sensory primary cilium of vertebrate photoreceptor cells houses thousands of photosensitive disk membranes that are renewed continuously throughout our lifespan. (jneurosci.org)
- Figures 323 & 324 from Chapter 13 (Cilia and Flagella) of 'The Cell' by Don W. Fawcett M.D. The outer segments of the rods and cones of the vertebrate retina and many photoreceptors of invertebrates b. (cellimagelibrary.org)
Retinas6
- The two-year research project, "Nanoparticle-based Photo-activator of Voltage-gated Sodium Channels," will support development and testing of the device in nerve cell preparations including isolated cells obtained from rat retinas. (uic.edu)
- Here, we performed a lineage analysis of Math5-expressing cells in developing mouse retinas using a conditional GFP reporter (Z/EG) activated by a Math5-Cre knock-in allele. (elsevierpure.com)
- While mouse retinal electroporation, both in vivo and ex vivo, has been developed and extensively described by Matsuda and Cepko(6-7,9), we have recently developed a simple approach to quantify the activity of photoreceptor-specific CREs in electroporated mouse retinas(10). (wustl.edu)
- Most vertebrates have a preponderance of rod photoreceptors in their retinas and such animals are very good at hunting and movement at night because of their very sensitive scotopic visual systems. (utah.edu)
- 1994). The immunocytochemical staining and confocal microscopy is now the most illustrative way of seeing the rod bipolar cells in mammalian retinas (Cuenca personal communication) (Fig. 7). (utah.edu)
- But mice who had the PDE6β gene mutation corrected through the PE SpRY system had much thicker retinas containing numerous rod cells. (scienceboard.net)
Subset of retinal gangl1
- We now know that a small subset of retinal ganglion cells are directly photosensitive and utilize an opsin/vitamin A-based photopigment called melanopsin maximally sensitive in the blue part of the spectrum. (ox.ac.uk)
Affects6
- This research has been extended to include how aging affects retinal and photoreceptor function. (nih.gov)
- How the remodeled retinal circuit affects visual processing following rod rescue is not known. (duke.edu)
- Although light affects rod photoreceptors primarily, cones seem to be more resilient surviving for a prolonged period of time after light exposure. (nature.com)
- Abnormal lysosomal activation or inhibition has dramatic consequences on photoreceptor cell homeostasis and impacts extensive cellular function, which in turn affects vision. (irrf.org)
- Ferroptosis is an iron-dependent cell death and affects efficacies of multiple antitumor regimens, showing a great potential in cancer therapy. (bvsalud.org)
- CAR affects both rods and cones, whereas MAR is typically characterized by antibodies directed toward bipolar cells that interfere with rod function. (medscape.com)
Mice12
- Goldberg and colleagues have demonstrated through a series of interventions in mice with optic nerve injury that they can successfully regenerate retinal ganglion cells axons, which form the optic nerve that transmits visual information from the retina to the brain. (nih.gov)
- In this next research phase they hope to identify genes and proteins that help or hinder this ability of retinal ganglion cells to regenerate, grow axons to a target and become functional in mice. (nih.gov)
- Low-level gestational lead exposure increases retinal progenitor cell proliferation and rod photoreceptor and bipolar cell neurogenesis in mice. (cdc.gov)
- Recently, we generated R91W;Nrl −/− double-mutant mice, which display a well-ordered all-cone retina with normal retinal vasculature and a strong photopic function that generates useful vision. (nature.com)
- While exposure of wt mice resulted in massive pyknosis in a focal region of the outer nuclear layer (ONL), the exposure of R91W;Nrl −/− mice led to additional cell death detected within the inner nuclear layer. (nature.com)
- This was accompanied by retinal swelling and the appearance of cystoid spaces in both inner and ONLs of R91W;Nrl −/− mice indicating edema in affected areas. (nature.com)
- Collectively, our data suggest that exposure of R91W;Nrl −/− mice to blue light not only induces cone cell death but also disrupts the inner blood-retinal barrier. (nature.com)
- 4 Therefore, the impact of the R91W mutation on cones can be analyzed without the 'contaminating' presence of rods in R91W;Nrl −/− mice. (nature.com)
- Retinal functional alterations in mice lacking intermediate filament proteins glial fibrillary acidic protein and vimentin. (lu.se)
- When assaying photoreceptor cis-regulatory activity, electroporation is usually performed in newborn mice (postnatal day 0, P0) which is the time of peak rod production(11-12). (wustl.edu)
- Given the high rate of rod birth in newborn mice and the fact that rods constitute more than 70% of the cells in the adult mouse retina, the majority of cells that are electroporated at P0 are rods. (wustl.edu)
- The discovery that mice lacking rods and cones are capable of regulating their circadian rhythms by light provided the conceptual framework for the discovery of an entirely new photoreceptor system within the mammalian eye. (ox.ac.uk)
Progressive retinal1
- Progressive Retinal Atrophy rcd4 is an eye disease that is inherited in an autosomal recessive manner. (genocan.eu)
Mammalian4
- We show that the adult mammalian neural retina exhibits a surprising degree of plasticity following rescue of rod photoreceptors. (duke.edu)
- To identify the full set of genes expressed by mammalian rods, we conducted serial analysis of gene expression (SAGE) by using libraries generated from mature and developing mouse retina. (johnshopkins.edu)
- Both Golgi impregnation of single rod bipolar cells (Fig. 6) and immunocytochemical staining of rod bipolar cell populations with protein kinase C (PKC) (Fig. 7) show the characteristic morphology of the rod bipolar cell type in mammalian retina (Kolb et al. (utah.edu)
- Two amacrine cells are key in the rod pathway circuitry through the mammalian retina (Fig. 10). (utah.edu)
Cones and rods3
- Under current-clamp conditions, blocking h currents (hyperpolarization-activated cationic currents) with Cs + , Tl + , or ZD7288 hyperpolarized the resting potentials of cones and rods by ∼10 to 15 mV, and surprisingly generated spontaneous action potentials. (fujita-hu.ac.jp)
- SCN2 Na + channel was observed in both cones and rods by single-cell RT-PCR analysis, suggesting that human photoreceptors express the SCN2 Na + channel. (fujita-hu.ac.jp)
- The optic nerve carries signals generated by the photoreceptors (cones and rods). (msdmanuals.com)
Blindness3
- A major cause of human blindness is the death of rod photoreceptors. (duke.edu)
- A study at Penn, supported by MVRF, discovered that the same cell death pathway is involved in 3 forms of blindness. (mvrf.org)
- In people with the complete form of X-linked congenital stationary night blindness (resulting from NYX mutations), the function of rods is severely disrupted, while the function of cones is only mildly affected. (medlineplus.gov)
Proliferation2
- Additionally, in vitro and vivo experiments validated PKD2 promoted proliferation, migration and invasion of LUAD cells. (bvsalud.org)
- Following 2 days of culture, cells on the coverslips were fixed in 4% paraformaldehyde at 4C for 10 min and processed for immunocytochemistry to detect proliferation-associated markers. (exposed-skin-care.net)
Neural3
- Cell adhesion molecules are known to play a pivotal role in assembling neural circuits. (nih.gov)
- In this study, we identified a new player in assembling neural circuits in the outer retina, the L1-family cell adhesion molecule Neurofascin (Nfasc). (nih.gov)
- Furthermore, SHH-treated cells had been shifted to neural lineage by expressing neuron-specific course III -tubulin (Tuj1), directing cell destiny to pole Cbz-B3A cells (14). (exposed-skin-care.net)
Differentiation5
- We previously discovered that that Maf-family bZIP transcription factor NRL is critical for rod photoreceptor fate and functional differentiation, and that loss of NRL leads to S-cones instead of rods. (nih.gov)
- To address these questions, particularly in a human-relevant system, we have focused upon the use of human induced pluripotent stem cells (iPSCs) to assess their ability to give rise to RGCs, with a particular emphasis upon ipRGC differentiation. (indianactsi.org)
- By immunostaining for cell type specific markers, I have documented the different stages of retinal differentiation and provided insight into the mechanisms of ipRGC differentiation. (indianactsi.org)
- This change in cell fate choices is accompanied by an up-regulation of NEUROD1, RXR and BHLHB5, the transcription factors essential for the differentiation of retinal cells other than RGCs. (elsevierpure.com)
- Subsequently, the cells were transferred to fresh culture medium, without purmorphamine or SHH-N, for a further 2 days to investigate Mller glia-derived cell differentiation. (exposed-skin-care.net)
Capacity of retinal2
- Researchers recently reported a technique that increases the regenerative capacity of retinal axons in a mouse model of optic nerve injury, a model commonly used to study glaucoma and other optic neuropathies. (nih.gov)
- These results suggested that the endogenous neurogenic capacity of retinal Mller glial cells could be improved by this little molecular agonist from the SHH signaling pathway. (exposed-skin-care.net)
Ganglion cell2
- No photoreceptors are found at the blind spot, the area where ganglion cell fibers are collected into the optic nerve and leave the eye. (wikipedia.org)
- A signal travels to the brain via the retinal ganglion cell axons. (nih.gov)
Fovea2
- The region of the retina with the highest density of photoreceptors is called the fovea . (informit.com)
- Rods are present in greater numbers than cones from 2 mm from the fovea to the far periphery. (utah.edu)
Membranes2
- 6 , 7 High photon flux, oxygen tension and the high levels of polyunsaturated fatty acids present in rod outer segment membranes make rod photoreceptor cells especially vulnerable to photochemical damage. (nature.com)
- This protein is anchored to photoreceptor membranes in retinal cells and deactivates G proteins in the rod and cone phototransduction cascades. (utsouthwestern.edu)
Outer segment1
- Finally, closest to the brain (and farthest from the field of view) is the outer segment, the part of the photoreceptor that absorbs light. (wikipedia.org)
Organoids derived2
- Our investigations utilize in vivo mouse retina and human retinal organoids derived from pluripotent stem cells as study systems. (nih.gov)
- The former edit allows for the purification of RGCs from retinal organoids derived from iPSCs, while the latter edit allows for the identification of ipRGCs among the broader RGC population. (indianactsi.org)
Optic nerve7
- Retinal nerve fibers exit the eye through the optic nerve, located nasally and on the same plane as the anatomical center of the retina. (medscape.com)
- There is no retinal tissue overlying the optic nerve head. (medscape.com)
- Each photoreceptor is joined to the optic nerve by a tiny nerve branch. (msdmanuals.com)
- The optic nerve is connected to nerve cells that carry signals to the vision center of the brain, where they are interpreted as visual images. (msdmanuals.com)
- The central retinal artery (the other major source of blood to the retina) reaches the retina near the optic nerve and then branches out within the retina. (msdmanuals.com)
- The central retinal vein exits the eye within the optic nerve. (msdmanuals.com)
- This is the point where the retinal arterioles and optic nerve enter the rear of the eyeball. (cdc.gov)
Transgenic2
- Background: Translating Ribosome Affinity Purification (TRAP), a method recently developed to generate cell type-specific translational profiles, relies on creating transgenic lines of animals in which a tagged ribosomal protein is placed under regulatory control of a cell type-specific promoter. (johnshopkins.edu)
- Results: Here, cell type-specific transgenic lines were generated to enable TRAP studies for retinal ganglion cells and rod photoreceptors in the Xenopus laevis retina. (johnshopkins.edu)
Ocular1
- Assuming that the ocular media (cornea, anterior chamber, lens, and vitreous) are not cloudy, the living retina can be examined using a direct or indirect ophthalmoscope or a retinal lens at the slit lamp. (medscape.com)
Gene11
- T) gene had clinical features characteristic of RP, with severely reduced retinal rod and cone function. (lu.se)
- We are using state-of-the-art next generation sequencing combined with bioinformatic strategies, and developing stem cell-based approaches for gene therapy and drug discovery. (nih.gov)
- In particular, for retinal gene therapy it would be highly advantageous to transduce a single cell type that spans the entire retina after an intravitreal injection of a gene delivery vehicle for the subsequent secretion of a general neuroprotective factor throughout the retina. (berkeley.edu)
- Cells were initially edited by the CRISPR/Cas9 system to express the Thy1 gene at the Brn3b locus and the tdTomato gene at the melanopsin locus. (indianactsi.org)
- Gene and protein expression studies may lead to a better understanding of the regulatory events involved in RGC apoptosis, and provide molecular targets for the development of new therapeutic agents with neuroprotective effects in order to prevent or delay the loss of ganglion cells in glaucoma. (uclahealth.org)
- Our goals were twofold: 1) to characterize the gene expression, protein expression, and activity of key synthesizing and regulating enzymes of energy metabolism in the whole mouse retina, retinal compartments, and/or cells and 2) to provide an integrative analysis of the results related to function. (molvis.org)
- The gene editing treatment prevented the death of rod and cone photoreceptors and restored normal electrical responses to light. (scienceboard.net)
- French biotechnology firm GenSight Biologics is highlighting its lenadogene neparvovec (Lumevoq) and GS030 gene therapies at the Cell & Gene Meeting. (scienceboard.net)
- Mutations in the NYX or CACNA1F gene disrupt the transmission of visual signals between photoreceptors and retinal bipolar cells, which impairs vision. (medlineplus.gov)
- In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. (medlineplus.gov)
- In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier . (medlineplus.gov)
Regeneration1
- Strittmatter and his team also are searching for genes that contribute to the regeneration of axons from retinal ganglion cells. (nih.gov)
Pathway4
- But what scientists did not know is how the mutations trigger a molecular signaling pathway that leads to the death of photoreceptor cells. (mvrf.org)
- In ciliated cells, including bovine and Xenopus laevis rod photoreceptors, P/rds was robustly sensitive to endoglycosidase H, which is consistent with its bypassing the medial Golgi and traversing the unconventional secretory pathway. (jneurosci.org)
- It has been established that RGCs die by apoptosis in glaucoma, but the exact pathway from death stimulus to cell death is not understood. (uclahealth.org)
- R&D Systems, Inc.) was added to purmorphamine-stimulated Mller glial cells to determine whether the Wnt pathway was involved. (exposed-skin-care.net)
Located in the retina1
- Retinal disintegration includes the damage of rods and photoreceptor cells, which are located in the retina. (infonettc.org)
Opsins1
- In cone cells, there are different types of opsins that combine with retinal to form pigments called photopsins. (wikipedia.org)
Molecular4
- Molecular cell. (arizona.edu)
- To investigate this mechanism, electrophysiological and molecular biological techniques were used on human cone and rod photoreceptors. (fujita-hu.ac.jp)
- The data confirmed that voltage-gated Na + channels were expressed not only in human rods but also in cones by electrophysiological and molecular biological experiments. (fujita-hu.ac.jp)
- Dr. Piri's research is aimed toward understanding the molecular mechanisms leading to retinal ganglion cells (RGC) death in glaucoma. (uclahealth.org)
Amacrine Cells4
- We show that during normal retinogenesis, Math5-lineage cells mostly develop into RGCs, horizontal cells, cone photoreceptors, rod photoreceptors, and amacrine cells. (elsevierpure.com)
- Interestingly, amacrine cells of Math5-lineage cells are predominately of GABAergic, cholinergic, and A2 subtypes, indicating that Math5 plays a role in amacrine subtype specification. (elsevierpure.com)
- This allows for both divergence of the rod signal and collection (convergence) of signals from many rods and rod bipolars, by means of these amacrine cells, before synaptic output to ganglion cells. (utah.edu)
- 3. Rod amacrine cells. (utah.edu)
Abstract1
- abstract = "Math5-null mutation results in the loss of retinal ganglion cells (RGCs) and in a concurrent increase of amacrine and cone cells. (elsevierpure.com)
Bipolar cell2
- Wayward bipolar cell dendrites establish contact with rods to support normal synaptic transmission, which is propagated to the retinal ganglion cells. (duke.edu)
- As was pointed out in a previous section, only one morphological type of bipolar cell has been found to make connections with the rod photoreceptors. (utah.edu)
Functioning rods and c1
- These non-photoreceptor cells remain physiologically capable of processing electrical and chemical signals, as in the normal retina, but in the absence of functioning rods and cones, they lack light-responsive input signals," Dr. Pepperberg said. (uic.edu)
Mutations4
- How do inherited mutations affect photoreceptor homeostasis and cause cell death? (nih.gov)
- Can we find common cellular pathways associated with photoreceptor cell death caused by distinct genetic mutations? (nih.gov)
- Mutations in the genes encoding the CNGA3 and CNGB3 subunits of the cyclic nucleotide-gated (CNG) channel of cone photoreceptors have been associated with autosomal recessive achromatopsia. (jneurosci.org)
- In people with the incomplete form of the condition (resulting from CACNA1F mutations), rods and cones are both affected, although they retain some ability to detect light. (medlineplus.gov)
Synaptic structures2
- Electron microscopic analysis confirms that indeed there are abnormal synaptic structures with less dendrites of rod bipolars innervating rod terminals in loss of Nfasc animals. (nih.gov)
- As rods degenerate, synaptic structures between rod and rod bipolar cells disappear and the rod bipolar cells extend their dendrites and occasionally make aberrant contacts. (duke.edu)
Therapies1
- In parallel, we are designing viral mediated therapies for autosomal dominant and recessive retinal degnenerations. (berkeley.edu)
Pathways3
- We are now focused on delineating the transcription factors and signaling pathways that are responsible for generating photoreceptors from retinal progenitor cells. (nih.gov)
- The genetic and biochemical diversity of photoreceptor degnereration presents major challenges for therapy as there are many pathways to cell death. (berkeley.edu)
- Rod photoreceptors and rod-connected nerve cells through the retina are responsible for pathways concerned with night vision and increased sensitivity of our visual system under what is called scotopic conditions (conditions of very little ambient light). (utah.edu)
Retina contains1
- The retina contains colour sensitive cells, which help one to perceive and differentiate colours. (infonettc.org)
Signals4
- The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiation) into signals that can stimulate biological processes. (wikipedia.org)
- In a healthy eye, bipolar cells receive signals from photoreceptor cells across a synapse and then transmit this information either directly or indirectly to retinal ganglion cells. (nih.gov)
- They are receptor nerve cells that emit electrical signals when light hits them. (informit.com)
- The NYX and CACNA1F proteins ensure that visual signals are passed from rods and cones to other retinal cells called bipolar cells, which is an essential step in the transmission of visual information from the eyes to the brain. (medlineplus.gov)
Mechanisms3
- The answers to these questions will be valuable for delineating pathogenic mechanisms that contribute to photoreceptor cell death. (nih.gov)
- Collectively, these data suggest that Math5 regulates the generation of multiple retinal cell types via different mechanisms during retinogenesis. (elsevierpure.com)
- Lysosomes are membrane-bound cell organelles that respond to nutrient changes and are implicated in cell homeostasis and clearance mechanisms, allowing effective adaption to specific cellular needs. (irrf.org)
Proteins in the rod1
- Disruption of Nfasc using a conditional knockout allele results in selective loss of pre- and post-synaptic proteins in the rod synaptic layer but not in the cone synaptic layer. (nih.gov)
Rhodopsin3
- In rod cells, these together are called rhodopsin. (wikipedia.org)
- The photoreceptor sensory cilium is recognized for fast membrane renewal, for which rhodopsin and peripherin/rds (P/rds) play critical roles. (jneurosci.org)
- Because rhodopsin is known to traffic through conventional secretion, this study of P/rds suggests that both conventional secretion and unconventional secretion need to cooperate for the renewal of the photoreceptor sensory cilium. (jneurosci.org)
Humans2
Regenerative1
- Cell transdifferentiation methodology To examine the regenerative potential of Mller glial cells, 1104 cells/ml were plated on poly-D-lysine (500 g/ml) and laminin (5 g/ml) coated glass coverslips. (exposed-skin-care.net)
Disorders4
- Such changes are broadly observed in blinding disorders caused by photoreceptor cell death and are thought to occur in response to deafferentation. (duke.edu)
- SIGNIFICANCE STATEMENT Current strategies for treatment of neurodegenerative disorders are focused on the repair of the primary affected cell type. (duke.edu)
- Paraneoplastic and autoimmune retinopathies belong to a spectrum of uncommon ophthalmic disorders in which autoantibodies directed at various retinal proteins cause progressive vision loss. (medscape.com)
- Retinal disorders are often diagnosed and treated by an ophthalmologist. (msdmanuals.com)
Subtypes1
- In the absence of Math5, more Math5-lineage cells undergo cell fate conversion from RGCs to the above retinal cell subtypes, and occasionally to cone-bipolar cells and Müller cells. (elsevierpure.com)
