what is the postsynaptic density
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Postsynaptic density The postsynaptic density (PSD) is a protein dense specialization attached to the postsynaptic membrane.PSDs were originally identified by electron microscopy as an electron-dense region at the membrane of a postsynaptic neuron.he structure and composition of the PSD have been the focus of numerous molecular studies of synaptic plasticity, a cellular model of learning and memory. PSDs are sized on the order of 250 to 500 nanometres in diameter and 25 to 50 nanometres in thickness, depending on the activity state of the synapse.
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Postsynaptic density Many proteins in the PSD are involved in the regulation of synaptic function. Key among these, are postsynaptic density-95 (PSD95), neuroligin (a cellular adhesion molecule), NMDA receptors, AMPA receptors, calcium/calmodulin-dependent protein kinase II and actin.
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Chemical synapse Desensitization of the postsynaptic receptors is a decrease in response to the same neurotransmitter stimulus. It means that the strength of a synapse may in effect diminish as a train of action potentials arrive in rapid succession – a phenomenon that gives rise to the so-called frequency dependence of synapses.
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The postsynaptic density Abstract. The postsynaptic density is a specialization of the nerve cell's submembrane cytoskeleton that is hypothesized to participate in the regulation of synaptic adhesion, transmitter receptor clustering, and modulation of receptor sensitivity.ntil recently, many of the major proteins in the highly insoluble postsynaptic density fraction remained uncharacterized. Modern immunological and microsequencing methods now make it possible to define more precisely the molecular composition and function of this intriguing organelle.
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- Bone density (or bone mineral density) is a medical term normally referring to the amount of mineral matter per square centimeter of bones. Bone density (or BMD) is used in clinical medicine as an indirect indicator of osteoporosis and fracture risk. Osteoporosis is defined as −2.5 or lower, meaning a bone density that is two and a half standard deviations below the mean of a thirty-year-old man/woman.
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- Density is a fundamental dynamical property of sea water and is defined to by the ratio of mass divided by volume. The density of seawater is between 1.02 and 1.04 g/cm3 over most of the ocean. Smaller values are near the surface and in the tropics.
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What Is the Difference Between Density and Specific Gravity? Density is the mass of a substance per unit volume. The density of water is 1 gram per milliliter. Substances with densities above 1 gram per milliliter sink in water, while substances with densities below 1 gram per milliliter float.
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Muscle The density of mammalian skeletal muscle tissue is about 1.06 kg/liter. This can be contrasted with the density of adipose tissue (fat), which is 0.9196 kg/liter. This makes muscle tissue approximately 15% denser than fat tissue.
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Sodium-Calcium Exchange in Cardiac Cells Intracellular calcium concentrations in both cardiac and vascular smooth muscle cells range from 10 -7 to 10 -5 M. Extracellular concentration of calcium is about 2 × 10 -3 M (2 mM).
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Soil Most soils have a dry bulk density (density of soil taking into account voids when dry) between 1.1 and 1.6 g/cm3, while the soil particle density is much higher, in the range of 2.6 to 2.7 g/cm3.
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Online Help A typical range of the compression index is from 0.1 to 10. Approximate values for homogeneous sand for the load range from 95 kPa to 3926 kPa attain the values from 0.05 to 0.06 for loose state and 0.02 to 0.03 for dense state.
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- Now the fact that. the densest known forms of matter have a density of. 1016 g/cm3 is most interesting in light of the fact men-. tioned above that the estimated energy density of the. quantum plenum of space is on the order of 1094.
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Polarization density In classical electromagnetism, polarization density is the vector field that expresses the density of permanent or induced electric dipole moments in a dielectric material. When a dielectric is placed in an external electric field, its molecules gain electric dipole moment and the dielectric is said to be polarized. The electric dipole moment induced per unit volume of the dielectric material is called the electric polarization of the dielectric. Polarization density also describes how a materia
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Electric Volume Charge Density Note that since electric charge can be negative or positive, the charge density can be negative, positive or zero. Simple Charge Density Example Suppose we have +5 [C] of electric charge uniformly (evenly) spread within a sphere of radius 2 meters.ote that since electric charge can be negative or positive, the charge density can be negative, positive or zero. Simple Charge Density Example Suppose we have +5 [C] of electric charge uniformly (evenly) spread within a sphere of radius 2 meters.
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Postsynaptic density Composition Edit. Many proteins in the PSD are involved in the regulation of synaptic function. Key among these, are postsynaptic density-95 (PSD95), neuroligin (a cellular adhesion molecule) NMDA receptors, AMPA receptors, calcium/calmodulin-dependent protein kinase II and actin.SDs are sized on the order of 0.25 to 0.5 micrometres in diameter and 0.025 to 0.05 micrometres in thickness, depending on the activity state of the synapse. Many proteins in the PSD are involved in the regulation of synaptic function.
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Neurons and Nervous System an excitatory postsynaptic potential (EPSP) is a temporary depolarization of postsynaptic membrane potential caused by the flow of positively charged ions into the postsynaptic cell as a result of opening of ligand-sensitive channels.
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Transition to Seizure: Ictal Discharge Is Preceded by Exhausted Presynaptic GABA Release in the Hippocampal CA3 Region Neurons in the CA3 region have enhanced cellular excitability and synaptic connectivity because of their recurrent circuitry (Wittner and Miles, 2007). We propose that in the transition period of the low-Mg 2+ /high-K + seizure model, interictal events are largely dependent on the GABAergic responses.
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- A presynaptic neuron has several specialized structures that distinguish it from a postsynaptic neuron. The terminal button of the presynaptic neuron’s axon contains mitochondria as well as microtubules that transport the neurotransmitters from the cell body (where they are produced) to the tip of the axon.ABA (gamma-aminobutyric acid) is an inhibitory neurotransmitter that is very widely distributed in the neurons of the cortex. GABA contributes to motor control, vision, and many other cortical functions. It also regulates anxiety.
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Chapter 48 the motor neuron is considered the presynaptic cell and the skeletal muscle is the postsynaptic cell. For a neuron with an initial membrane potential at -70 mV, an increase in the movement of potassium ions out of that neuron's cytoplasm would result in. the hyperpolarization of the neuron.
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- be those which give readings in terms of optical density (log Io/I). With cultures well dispersed, it is generally found that optical. density remains proportional to bacterial density throughout the. positive phases of growth of the cultures (11).
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sumÂ·maÂ·tion 2 (in neurology) the concentration of a neurotransmitter at a synapse, either by increasing the frequency of nerve impulses in each fiber (temporal summation) or by increasing the number of fibers stimulated (spatial summation) , so that the threshold of the postsynaptic neuron is overcome and an impulse is transmitted.hysiological summation in synapses is a characteristic of the mammalian nervous system. It may be spatial, with additional synaptic junctions participating, or temporal, when succeeding stimuli catch up with the as-yet undischarged neurotransmitter.
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DYNAMIC RANGE IN DIGITAL PHOTOGRAPHY The overall dynamic range in terms of density is therefore the maximum pigment density (Dmax), minus the minimum pigment density (Dmin). Unlike powers of 2 for f-stops, density is measured using powers of 10 (just as the Richter scale for earthquakes).
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- Seawater Properties that Control Density. Density is defined as the mass of water per unit volume and has units of grams per cubic centimeter (g /cm3), kilograms per liter (kg/ L) or kilograms per cubic meter (kg/m3). The density of fresh water at 4 C is 1.0000 g/cm3 or 1.000 kg/liter or 1000 kg/m3.
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PSA 1 PSA density—a comparison of the PSA concentration and the volume of the prostate (as measured by ultrasound); if the PSA level is greater than what one would expect given the size of the prostate, the chance that a cancer is present may be higher.
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- Density is defined as the mass of water per unit volume and has units of grams per cubic centimeter (g /cm3), kilograms per liter (kg/ L) or kilograms per cubic meter (kg/m3). The density of fresh water at 4 C is 1.0000 g/cm3 or 1.000 kg/liter or 1000 kg/m3.ensity is defined as the mass of water per unit volume and has units of grams per cubic centimeter (g /cm3), kilograms per liter (kg/ L) or kilograms per cubic meter (kg/m3). The density of fresh water at 4 C is 1.0000 g/cm3 or 1.000 kg/liter or 1000 kg/m3.
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Density The reciprocal of the density of a substance is occasionally called its specific volume, a term sometimes used in thermodynamics. Density is an intensive property in that increasing the amount of a substance does not increase its density; rather it increases its mass.s there are many units of mass and volume covering many different magnitudes there are a large number of units for mass density in use. The SI unit of kilogram per cubic metre (kg/m 3) and the cgs unit of gram per cubic centimetre (g/cm 3) are probably the most commonly used units for density.