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Binding Potential
In pharmacokinetics and receptor-ligand kinetics the binding potential (BP) is a combined measure of the density of "available" neuroreceptors and the affinity of a drug to that neuroreceptor. Description Consider a ligand receptor binding system. Ligand with a concentration ''L'' associates with a receptor of concentration or availability ''R'' to form a ligand-receptor complex with concentration ''RL''. The binding potential is then the ratio ligand-receptor complex to free ligand at equilibrium and in the limit of L tending to 0, and is given symbol BP: BP=\frac\bigg, _ This quantity, originally defined by Mintun, describes the capacity of a receptor to bind ligand. It is a limit (L << Ki) of the general receptor association equation: and is thus also equivalent to: These equations apply equally when measuring the total receptor density or the residual receptor density available after binding to second ligand - availability. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharmacokinetics
Pharmacokinetics (from Ancient Greek ''pharmakon'' "drug" and ''kinetikos'' "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to determining the fate of substances administered to a living organism. The substances of interest include any chemical xenobiotic such as: pharmaceutical drugs, pesticides, food additives, cosmetics, etc. It attempts to analyze chemical metabolism and to discover the fate of a chemical from the moment that it is administered up to the point at which it is completely eliminated from the body. Pharmacokinetics is the study of how an organism affects a drug, whereas pharmacodynamics (PD) is the study of how the drug affects the organism. Both together influence dosing, benefit, and adverse effects, as seen in PK/PD models. Overview Pharmacokinetics describes how the body affects a specific xenobiotic/chemical after administration through the mechanisms of absorption and distribution, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroreceptor
A neurotransmitter receptor (also known as a neuroreceptor) is a membrane receptor protein that is activated by a neurotransmitter. Chemicals on the outside of the cell, such as a neurotransmitter, can bump into the cell's membrane, in which there are receptors. If a neurotransmitter bumps into its corresponding receptor, they will bind and can trigger other events to occur inside the cell. Therefore, a membrane receptor is part of the molecular machinery that allows cells to communicate with one another. A neurotransmitter receptor is a class of receptors that specifically binds with neurotransmitters as opposed to other molecules. In postsynaptic cells, neurotransmitter receptors receive signals that trigger an electrical signal, by regulating the activity of ion channels. The influx of ions through ion channels opened due to the binding of neurotransmitters to specific receptors can change the membrane potential of a neuron. This can result in a signal that runs along the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Affinity (pharmacology)
In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from ''ligare'', which means 'to bind'. In protein-ligand binding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein. The binding typically results in a change of conformational isomerism (conformation) of the target protein. In DNA-ligand binding studies, the ligand can be a small molecule, ion, or protein which binds to the DNA double helix. The relationship between ligand and binding partner is a function of charge, hydrophobicity, and molecular structure. Binding occurs by intermolecular forces, such as ionic bonds, hydrogen bonds and Van der Waals forces. The association or docking is actually reversible through dissociation. Measurably irreversible covalent bonding between a ligand and target molecule is atypical in biological systems. In contrast to the definition of liga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis bases. The nature of metal–ligand bonding can range from covalent to ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environmental chemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annals Of Neurology
''Annals of Neurology'' is a peer-reviewed medical journal publishing articles of "broad interest in neurology, particularly those with high impact in understanding the mechanisms and treatment of diseases of the human nervous system." The journal has a 2020 ''Journal Citation Reports'' impact factor of 10.422, ranking it 9th out of 208 journals in the category "Clinical Neurology". History The ''Annals of Neurology'' was launched in 1977. Editors The following people have been editors-in-chief of the journal: * Clifford B. Saper, 2018present * Steven L. Hauser, 2006–2013 * Richard T. Johnson, 1997–2005 * Robert A. Fishman, 1993–1997 * Arthur K. Asbury, 1985–1992 * Fred Plum Fred Plum (January 10, 1924 – June 11, 2010) was an American neurologist who developed the terms "persistent vegetative state" and "locked-in syndrome" as part of his continuing research on consciousness and comas and care of the comatose. ..., 1977–1984 References External links * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Positron Emission Tomography
Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in Metabolism, metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption. Different tracers are used for various imaging purposes, depending on the target process within the body. For example, 18F-FDG, -FDG is commonly used to detect cancer, Sodium fluoride#Medical imaging, NaF is widely used for detecting bone formation, and Isotopes of oxygen#Oxygen-15, oxygen-15 is sometimes used to measure blood flow. PET is a common medical imaging, imaging technique, a Scintigraphy#Process, medical scintillography technique used in nuclear medicine. A radiopharmaceutical, radiopharmaceutical — a radioisotope attached to a drug — is injected into the body as a radioactive tracer, tracer. When the radiopharmaceutical undergoes beta plus decay, a positron is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methods (journal)
''Methods'' is a peer-reviewed scientific journal covering research on techniques in the experimental biological and medical sciences. It absorbed two journals, ''ImmunoMethods'' and ''NeuroProtocols''. Abstracting and indexing The journal is abstracted and indexed in EMBASE, EMBiology, and Scopus. According to the ''Journal Citation Reports'', the journal has a 2021 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 4.647. References External links * Biochemistry journals English-language journals Elsevier academic journals Publications established in 1990 Research methods journals {{med-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Fraction
The free fraction is a parameter in pharmacokinetics and receptor-ligand kinetics. One speaks of two different free fractions: * ''Plasma free fraction'', previously referred to as ƒ1, is now referred to as ƒP according to consensus nomenclature. * ''Tissue free fraction'' (ƒND), previously referred to as ƒ2 The ''plasma free fraction'' is the fraction of the ligand at equilibrium in blood plasma that is not bound to plasma proteins. See also * Binding potential In pharmacokinetics and receptor-ligand kinetics the binding potential (BP) is a combined measure of the density of "available" neuroreceptors and the affinity of a drug to that neuroreceptor. Description Consider a ligand receptor binding syst ... References Others * Pharmacokinetics {{biochemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two Tissue Compartment Model
2 (two) is a number, numeral and digit. It is the natural number following 1 and preceding 3. It is the smallest and only even prime number. Because it forms the basis of a duality, it has religious and spiritual significance in many cultures. Evolution Arabic digit The digit used in the modern Western world to represent the number 2 traces its roots back to the Indic Brahmic script, where "2" was written as two horizontal lines. The modern Chinese and Japanese languages (and Korean Hanja) still use this method. The Gupta script rotated the two lines 45 degrees, making them diagonal. The top line was sometimes also shortened and had its bottom end curve towards the center of the bottom line. In the Nagari script, the top line was written more like a curve connecting to the bottom line. In the Arabic Ghubar writing, the bottom line was completely vertical, and the digit looked like a dotless closing question mark. Restoring the bottom line to its original horizonta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volume Of Distribution
In pharmacology, the volume of distribution (VD, also known as apparent volume of distribution, literally, ''volume of dilution'') is the theoretical volume that would be necessary to contain the total amount of an administered drug at the same concentration that it is observed in the blood plasma. In other words, it is the ratio of ''amount of drug in a body (dose)'' to ''concentration of the drug that is measured in blood, plasma, and un-bound in interstitial fluid''. The VD of a drug represents the degree to which a drug is distributed in body tissue rather than the plasma. VD is directly proportional with the amount of drug distributed into tissue; a higher VD indicates a greater amount of tissue distribution. A VD greater than the total volume of body water (approximately 42 liters in humans) is possible, and would indicate that the drug is highly distributed into tissue. In other words, the volume of distribution is smaller in the drug staying in the plasma than that of a dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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