|
Biotinylated Dextran Amine
Biotinylated dextran amines (BDA) are organic compounds used as anterograde and retrograde neuroanatomical tracers. They can be used for labeling the source as well as the point of termination of neural connections and therefore to study neural pathways. BDA is delivered into the nervous system by iontophoretic or pressure injection and visualized with an avidin-biotinylated horseradish peroxidase procedure, followed by a standard or metal-enhanced diaminobenzidine (DAB) reaction. Samples can then be analyzed by optical microscopy as well as by electron microscopy An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, electron microscopes have a .... High molecular weight BDA (10 kDa) yields sensitive and detailed labeling of axons and terminals, while low molecular weight BDA (3 kDa) yields sensitive and detailed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterograde Tracing
In neuroscience, anterograde tracing is a research method which is used to trace axonal projections from their source (the cell body or soma) to their point of termination (the synapse). A hallmark of anterograde tracing is the labeling of the presynaptic and the postsynaptic neuron(s). The crossing of the synaptic cleft is a vital difference between the anterograde tracers and the dye fillers used for morphological reconstruction. The complementary technique is '' retrograde tracing'', which is used to trace neural connections from their termination to their source (i.e. synapse to cell body). Both the anterograde and retrograde tracing techniques are based on the visualization of the biological process of axonal transport. The anterograde and retrograde tracing techniques allow the detailed descriptions of neuronal projections from a single neuron or a defined population of neurons to their various targets throughout the nervous system. These techniques allow the "mapping" of conn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retrograde Tracing
Retrograde tracing is a research method used in neuroscience to trace neural connections from their point of termination (the synapse) to their source (the cell body). Retrograde tracing techniques allow for detailed assessment of neuronal connections between a target population of neurons and their inputs throughout the nervous system. These techniques allow the "mapping" of connections between neurons in a particular structure (e.g. the eye) and the target neurons in the brain. The opposite technique is anterograde tracing, which is used to trace neural connections from their source to their point of termination (i.e. from cell body to synapse). Both the anterograde and retrograde tracing techniques are based on the visualization of axonal transport. Techniques Retrograde tracing can be achieved through various means, including the use of viral strains as markers of a cell’s connectivity to the injection site. The pseudorabies virus (PRV; Bartha strain), for example, may be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histochemical Tracer
A histochemical tracer is a compound used to reveal the location of cells and track neuronal projections. A neuronal tracer may be retrograde, anterograde, or work in both directions. A retrograde tracer is taken up in the terminal of the neuron and transported to the cell body, whereas an anterograde tracer moves ''away from the cell body'' of the neuron. List * Diamidino yellow * Fast blue * Horseradish peroxidase - retrograde * Cholera toxin B - retrograde * Pseudorabies virusKreier Felix et al 2006 * Hydroxystilbamidine - retrograde * Texas Red * Fluorescein isothiocyanate Fluorescein isothiocyanate (FITC) is a derivative of fluorescein used in wide-ranging applications including flow cytometry. First described in 1942, FITC is the original fluorescein molecule functionalized with an isothiocyanate reactive group ... Footnotes {{Reflist, 2 References * Kreier Felix; Kap Yolanda S; Mettenleiter Thomas C; van Heijningen Caroline; van der Vliet Jan; Kalsbeek Andries; Sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuron
A neuron, neurone, or nerve cell is an membrane potential#Cell excitability, electrically excitable cell (biology), cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all Animalia, animals except sponges and placozoa. Non-animals like plants and fungi do not have nerve cells. Neurons are typically classified into three types based on their function. Sensory neurons respond to Stimulus (physiology), stimuli such as touch, sound, or light that affect the cells of the Sense, sensory organs, and they send signals to the spinal cord or brain. Motor neurons receive signals from the brain and spinal cord to control everything from muscle contractions to gland, glandular output. Interneurons connect neurons to other neurons within the same region of the brain or spinal cord. When multiple neurons are connected together, they form what is called a neural circuit. A typical neuron consists of a cell bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neural Pathway
In neuroanatomy, a neural pathway is the connection formed by axons that project from neurons to make synapses onto neurons in another location, to enable neurotransmission (the sending of a signal from one region of the nervous system to another). Neurons are connected by a single axon, or by a bundle of axons known as a nerve tract, or fasciculus. Shorter neural pathways are found within grey matter in the brain, whereas longer projections, made up of myelinated axons, constitute white matter. In the hippocampus there are neural pathways involved in its circuitry including the perforant pathway, that provides a connectional route from the entorhinal cortex to all fields of the hippocampal formation, including the dentate gyrus, all CA fields (including CA1), and the subiculum. Descending motor pathways of the pyramidal tracts travel from the cerebral cortex to the brainstem or lower spinal cord. Ascending sensory tracts in the dorsal column–medial lemniscus pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iontophoresis
Iontophoresis is a process of transdermal drug delivery by use of a voltage gradient on the skin. Molecules are transported across the stratum corneum by electrophoresis and electroosmosis and the electric field can also increase the permeability of the skin. These phenomena, directly and indirectly, constitute active transport of matter due to an applied electric current. The transport is measured in units of chemical flux, commonly μmol/(cm2*hour). Iontophoresis has experimental, therapeutic and diagnostic applications. Uses Laboratory uses Iontophoresis is useful in laboratory experiments, especially in neuropharmacology. Transmitter molecules naturally pass signals between neurons. By microelectrophoretic techniques, including microiontophoresis, neurotransmitters and other chemical agents can be artificially administered very near living and naturally functioning neurons, the activity of which can be simultaneously recorded. This is used to elucidate their pharmacologica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horseradish Peroxidase
The enzyme horseradish peroxidase (HRP), found in the roots of horseradish, is used extensively in biochemistry applications. It is a metalloenzyme with many isoforms, of which the most studied type is C. It catalyzes the oxidation of various organic substrates by hydrogen peroxide. Structure The structure of the enzyme was first solved by X-ray crystallography in 1997; and has since been solved several times with various substrates. It is a large alpha-helical glycoprotein which binds heme as a redox cofactor. Substrates Alone, the HRP enzyme, or conjugates thereof, is of little value; its presence must be made visible using a substrate that, when oxidized by HRP using hydrogen peroxide as the oxidizing agent, yields a characteristic color change that is detectable by spectrophotometric methods. Numerous substrates for horseradish peroxidase have been described and commercialized to exploit the desirable features of HRP. These substrates fall into several distinct ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3,3'-Diaminobenzidine
3,3′-Diaminobenzidine (DAB) is an organic compound with the formula (C6H3(NH2)2)2. This derivative of benzidine is a precursor to polybenzimidazole, which forms fibers that are renowned for their chemical and thermal stability.Hans Schwenecke, Dieter Mayer "Benzidine and Benzidine Derivatives" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2005, Wiley-VCH, Weinheim. As its water-soluble tetrahydrochloride, DAB has been used in immunohistochemical staining of nucleic acids and proteins. Structure DAB is symmetric about the central carbon bond between both ring structures. In the crystal, the rings of each molecule are co-planar and the amine units connect molecules to form an intermolecular 3-dimensional hydrogen bond network. Preparation Diaminobenzidine, which is commercially available, is prepared by treating 3,3′-dichlorobenzidine with ammonia with a copper catalyst at high temperature and pressure, followed by acidic workup. An alternate synthesis route invo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Microscopy
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for by using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Microscopy
An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, electron microscopes have a higher resolving power than light microscopes and can reveal the structure of smaller objects. A scanning transmission electron microscope has achieved better than 50 pm resolution in annular dark-field imaging mode and magnifications of up to about 10,000,000× whereas most light microscopes are limited by diffraction to about 200 nm resolution and useful magnifications below 2000×. Electron microscopes use shaped magnetic fields to form electron optical lens systems that are analogous to the glass lenses of an optical light microscope. Electron microscopes are used to investigate the ultrastructure of a wide range of biological and inorganic specimens including microorganisms, cells, large molecules, biopsy samples, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
