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Dynorphin
Dynorphins (Dyn) are a class of opioid peptides that arise from the precursor protein prodynorphin. When prodynorphin is cleaved during processing by proprotein convertase 2 (PC2), multiple active peptides are released: dynorphin A, dynorphin B, and α/ β-neoendorphin. Depolarization of a neuron containing prodynorphin stimulates PC2 processing, which occurs within synaptic vesicles in the presynaptic terminal. Occasionally, prodynorphin is not fully processed, leading to the release of "big dynorphin". "Big dynorphin" is a 32-amino acid molecule consisting of both dynorphin A and dynorphin B. Dynorphin A, dynorphin B, and big dynorphin all contain a high proportion of basic amino acid residues, in particular lysine and arginine (29.4%, 23.1%, and 31.2% basic residues, respectively), as well as many hydrophobic residues (41.2%, 30.8%, and 34.4% hydrophobic residues, respectively). Although dynorphins are found widely distributed in the CNS, they have the highest concentra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opioid Peptides
Opioid peptides or opiate peptides are peptides that bind to opioid receptors in the brain; opiates and opioids mimic the effect of these peptides. Such peptides may be produced by the body itself, for example endorphins. The effects of these peptides vary, but they all resemble those of opiates. Brain opioid peptide systems are known to play an important role in motivation, emotion, attachment theory, attachment behaviour, the response to Stress (biology), stress and pain, Hunger (motivational state), control of food intake, and the rewarding effects of alcohol (drug), alcohol and nicotine. Opioid-like peptides may also be absorbed from partially digestion, digested food (casomorphins, Gluten exorphin, exorphins, and rubiscolins). opioid food peptides, Opioid peptides from food typically have lengths between 4–8 amino acids. Endogenous opioids are generally much longer. Opioid peptides are released by post-translational proteolytic cleavage of Protein precursor, precursor pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynorphin A
Dynorphin A is a dynorphin, an endogenous opioid peptide that activates the κ-opioid receptor. Its amino acid sequence is Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys, a tridecapeptide. Dynorphin A1–8 is a truncated form of dynorphin A with the amino acid sequence: Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile. Dynorphin A1–8 is an agonist at the mu-, kappa-, and delta-opioid receptor Opioid receptors are a group of inhibitory G protein-coupled receptors with opioids as ligands. The endogenous opioids are dynorphins, enkephalins, endorphins, endomorphins and nociceptin. The opioid receptors are ~40% identical to somatostati ...s; it has the highest binding affinity for the kappa-opioid receptor. Structures of dynorphin A bound to the κ-opioid receptor have been reported. References Neuropeptides Kappa-opioid receptor agonists Opioid peptides {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynorphin B
Dynorphin B, also known as rimorphin, is a form of dynorphin and an endogenous opioid peptide with the amino acid sequence Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Gln-Phe-Lys-Val-Val-Thr. Dynorphin B is generated as a proteolytic cleavage product of leumorphin, which in turn is a cleavage product of preproenkephalin B (prodynorphin). Dynorphin B has an identical N-terminal sequence, but different C-terminal sequence to dynorphin A. In an alanine scan of the non-glycine residues of dynorphin B, it was discovered that Tyr1 and Phe4 residues are critical for both opioid receptor affinity and κ-opioid receptor agonist potency, Arg6 and Arg7 promote κ-opioid affinity and Lys10 contributes to the opioid receptor affinity. Inducers of dynorphin B Cannabinoid CP55,940 and △9-tetrahydrocannabinol (△9-THC) can induce the release of dynorphin B, which in return acts as an agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Big Dynorphin
Big dynorphin is an endogenous opioid peptide of the dynorphin family that is composed of both dynorphin A and dynorphin B. It is derived from the precursor protein prodynorphin, encoded by the ''PDYN'' gene. Big dynorphin is notable for its potent activity at opioid receptors and its role in modulating pain, stress, emotion, and neurophysiological functions such as learning and memory. Big dynorphin has the amino acid sequence: Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys-Trp-Asp-Asn-Gln-Lys-Arg-Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Gln-Phe-Lys-Val-Val-Thr. It has nociceptive and anxiolytic-like properties, as well as effects on memory in mice. Big dynorphin is a principal endogenous Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an ..., agonist at the human kappa-opioid receptor. Rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
κ-opioid Receptor
The κ-opioid receptor or kappa opioid receptor, abbreviated KOR or KOP for its ligand ketazocine, is a G protein-coupled receptor that in humans is encoded by the ''OPRK1'' gene. The KOR is coupled to the G protein Gi/G0 and is one of four related receptors that bind opioid-like compounds in the brain and are responsible for mediating the effects of these compounds. These effects include altering nociception, consciousness, motor control, and mood. Dysregulation of this receptor system has been implicated in alcohol and drug addiction. The KOR is a type of opioid receptor that binds the opioid peptide dynorphin as the primary endogenous ligand (substrate naturally occurring in the body). In addition to dynorphin, a variety of natural alkaloids, terpenes and synthetic ligands bind to the receptor. The KOR may provide a natural addiction control mechanism, and therefore, drugs that target this receptor may have therapeutic potential in the treatment of addiction . There ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prodynorphin
Prodynorphin, also known as proenkephalin B, is an opioid polypeptide hormone involved with chemical signal transduction and cell communication. The gene for prodynorphin is expressed in the endometrium and the striatum, and its gene map locus is 20pter-p12. Prodynorphin is a basic building-block of endorphins, the chemical messengers in the brain that appear most heavily involved in the anticipation and experience of pain and the formation of deep emotional bonds, and that are also critical in learning and memory. The gene is thought to influence perception, as well as susceptibility to drug dependence, and is expressed more readily in human beings than in other primates. Evolutionary implications Most humans have multiple copies of the regulatory gene sequence for prodynorphin, which is virtually identical among all primates, whereas other primates have only a single copy. In addition, most Asian populations have two copies of the gene sequence for prodynorphin, whereas East Afri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supraoptic Nucleus
The supraoptic nucleus (SON) is a nucleus of magnocellular neurosecretory cells in the hypothalamus of the mammalian brain. The nucleus is situated at the base of the brain, adjacent to the optic chiasm. In humans, the SON contains about 3,000 neurons. Function The cell bodies produce the peptide hormone vasopressin, which is also known as anti-diuretic hormone (ADH), and the peptide hormone oxytocin. Both of these peptides are released from the posterior pituitary. ADH travels via the bloodstream to its target cells in the papillary ducts in the kidneys, enhancing water reabsorption. Oxytocin travels via the bloodstream to act at the mammary glands and the uterus. In the cell bodies, the hormones are packaged in large, membrane-bound vesicles that are transported down the axons to the nerve endings. The secretory granules are also stored in packets along the axon called Herring bodies. Similar magnocellular neurons are also found in the paraventricular nucleus. Signaling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotransmitters
A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotransmitters are released from synaptic vesicles into the synaptic cleft where they are able to interact with neurotransmitter receptors on the target cell. Some neurotransmitters are also stored in large dense core vesicles. The neurotransmitter's effect on the target cell is determined by the receptor it binds to. Many neurotransmitters are synthesized from simple and plentiful precursors such as amino acids, which are readily available and often require a small number of biosynthetic steps for conversion. Neurotransmitters are essential to the function of complex neural systems. The exact number of unique neurotransmitters in humans is unknown, but more than 100 have been identified. Common neurotransmitters include glutamate, GABA, acetylcholine, glyci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
μ-opioid Receptor
The μ-opioid receptors (MOR) are a class of opioid receptors with a high affinity for enkephalins and beta-endorphin, but a low affinity for dynorphins. They are also referred to as μ(''mu'')-opioid peptide (MOP) receptors. The prototypical μ-opioid receptor agonist is morphine, the primary psychoactive alkaloid in opium and for which the receptor was named, with Mu (letter), mu being the first letter of Morpheus, the compound's namesake in the original Greek. It is an inhibitory G-protein coupled receptor that activates the Gi alpha subunit, Gi alpha subunit, inhibiting adenylate cyclase activity, lowering Cyclic adenosine monophosphate, cAMP levels. Structure The structure of the inactive μ-opioid receptor has been determined with the antagonists Beta-Funaltrexamine, β-FNA and alvimopan. Many structures of the active state are also available, with agonists including DAMGO, Β-Endorphin, β-endorphin, fentanyl and morphine. The structure with the agonist BU72 has the h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G-protein-coupled Receptor
G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large protein family, group of evolutionarily related proteins that are cell surface receptors that detect molecules outside the cell (biology), cell and activate cellular responses. They are coupled with G proteins. They pass through the cell membrane seven times in the form of six loops (three extracellular loops interacting with ligand molecules, three intracellular loops interacting with G proteins, an N-terminus, N-terminal extracellular region and a C-terminal intracellular region) of amino acid residues, which is why they are sometimes referred to as seven-transmembrane receptors. Text was copied from this source, which is available under Attribution 2.5 Generic (CC BY 2.5) licence/ref> Ligands can bind either to the extracellular N-terminus and loops (e.g. glutama ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippocampus
The hippocampus (: hippocampi; via Latin from Ancient Greek, Greek , 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the subiculum are components of the hippocampal formation located in the limbic system. The hippocampus plays important roles in the Memory consolidation, consolidation of information from short-term memory to long-term memory, and in spatial memory that enables Navigation#Navigation in spatial cognition, navigation. In humans, and other primates the hippocampus is located in the archicortex, one of the three regions of allocortex, in each cerebral hemisphere, hemisphere with direct neural projections to, and reciprocal indirect projections from the neocortex. The hippocampus, as the medial pallium, is a structure found in all vertebrates. In Alzheimer's disease (and other forms of dementia), the hippocampus is one of the first regions of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
δ-opioid Receptor
The δ-opioid receptor, also known as delta opioid receptor or simply delta receptor, abbreviated DOR or DOP, is an inhibitory 7-transmembrane G-protein coupled receptor coupled to the G protein Gi alpha subunit, Gi/G0 and has enkephalins as its endogenous ligands. The regions of the brain where the δ-opioid receptor is largely expressed vary from species model to species model. In humans, the δ-opioid receptor is most heavily expressed in the basal ganglia and Neocortex, neocortical regions of the brain. Function The endogenous system of opioid receptors is well known for its analgesic potential; however, the exact role of δ-opioid receptor activation in pain modulation is largely up for debate. This also depends on the model at hand since receptor activity is known to change from species to species. Activation of delta receptors produces analgesia, perhaps as significant potentiators of μ-opioid receptor agonists. However, it seems like delta agonism provides heavy poten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
