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Epipregnanolone
Epipregnanolone, also known as 3β-hydroxy-5β-pregnan-20-one, 3β,5β-tetrahydroprogesterone, or 3β,5β-THP, is an endogenous neurosteroid. It acts as a negative allosteric modulator of the GABAA receptor and reverses the effects of potentiators like allopregnanolone. Epipregnanolone is biosynthesized from progesterone by the actions of 5β-reductase and 3β-hydroxysteroid dehydrogenase, with 5β-dihydroprogesterone as the intermediate in this two-step transformation. Epipregnanolone is not a progestogen itself, but via metabolization into other steroids, behaves indirectly as one. The sulfate of epipreganolone, epipregnanolone sulfate, is a negative allosteric modulator of the NMDA and GABAA receptors and also acts as a TRPM3 channel activator. Chemistry See also * Isopregnanolone * 3β-Dihydroprogesterone * Pregnanolone * 5α-Dihydroprogesterone * 3β-Androstanediol 3β-Androstanediol, also known as 5α-androstane-3β,17β-diol, and sometimes shortened in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epipregnanolone Sulfate
Epipregnanolone, also known as 3β-hydroxy-5β-pregnan-20-one, 3β,5β-tetrahydroprogesterone, or 3β,5β-THP, is an endogenous neurosteroid. It acts as a negative allosteric modulator of the GABAA receptor and reverses the effects of potentiators like allopregnanolone. Epipregnanolone is biosynthesized from progesterone by the actions of 5β-reductase and 3β-hydroxysteroid dehydrogenase, with 5β-dihydroprogesterone as the intermediate in this two-step transformation. Epipregnanolone is not a progestogen itself, but via metabolization into other steroids, behaves indirectly as one. The sulfate of epipreganolone, epipregnanolone sulfate, is a negative allosteric modulator of the NMDA and GABAA receptors and also acts as a TRPM3 channel activator. Chemistry See also * Isopregnanolone * 3β-Dihydroprogesterone * Pregnanolone * 5α-Dihydroprogesterone * 3β-Androstanediol 3β-Androstanediol, also known as 5α-androstane-3β,17β-diol, and sometimes shortened in the lite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5α-Dihydroprogesterone
5α-Dihydroprogesterone (5α-DHP, allopregnanedione, or 5α-pregnane-3,20-dione) is an endogenous progestogen and neurosteroid that is synthesized from progesterone. It is also an intermediate in the synthesis of allopregnanolone and isopregnanolone from progesterone. 5α-DHP is metabolized by the aldo-keto reductases (AKRs) AKR1C1, AKR1C2, and AKR1C4 with high catalytic efficiency. AKR1C1 preferentially forms 20α-hydroxy-5α-pregnane-3-one while AKR1C2 preferentially forms allopregnanolone. Similarly AKR1C1 reduces and consequently inactivates allopregnanolone into 5α-pregnane-3α,20α-diol. In contrast to the other AKRs, AKR1C3 has low catalytic efficiency for reduction of 5α-DHP. These AKRs are highly expressed in the human liver and mammary gland but have relatively modest expression in the human brain and uterus. 5α-DHP is an agonist of the progesterone receptor and a positive allosteric modulator of the GABAA receptor (albeit with an affinity for this receptor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isopregnanolone
Isopregnanolone, also known as isoallopregnanolone and epiallopregnanolone, as well as sepranolone (), and as 3β-hydroxy-5α-pregnan-20-one or 3β,5α-tetrahydroprogesterone (3β,5α-THP), is an endogenous neurosteroid and a natural 3β-epimer of allopregnanolone.Öfverman, C., Strömberg, J., Birzniece, V., Turkmen, S., Hill, M., Lundgren, P., ... & Johansson, I. M. (2009). The progesterone metabolite isoallopregnanolone is a subunit-selective antagonist of the GABA-A receptor. Chicago It has been reported to act as a subunit-selective negative allosteric modulator of the GABAA receptor, and antagonizes in animals and humans some but not all of the GABAA receptor-mediated effects of allopregnanolone, such as anesthesia, sedation, and reduced saccadic eye movements, but not learning impairment. Isopregnanolone has no hormonal effects and appears to have no effect on the GABAA receptor by itself; it selectively antagonizes allopregnanolone and does not affect the effects of othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endogenous
Endogenous substances and processes are those that originate from within a living system such as an organism, tissue, or cell. In contrast, exogenous substances and processes are those that originate from outside of an organism. For example, estradiol is an endogenous estrogen hormone produced within the body, whereas ethinylestradiol Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological disord ... is an exogenous synthetic estrogen, commonly used in birth control pills. References External links *{{Wiktionary-inline, endogeny Biology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GABAA Receptor Negative Allosteric Modulators
The GABAA receptor (GABAAR) is an ionotropic receptor and ligand-gated ion channel. Its endogenous ligand is γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system. Upon opening, the GABAA receptor on the postsynaptic cell is selectively permeable to chloride ions (Cl−) and, to a lesser extent, bicarbonate ions (HCO3−). Depending on the membrane potential and the ionic concentration difference, this can result in ionic fluxes across the pore. If the membrane potential is higher than the equilibrium potential (also known as the reversal potential) for chloride ions, when the receptor is activated Cl− will flow into the cell. This causes an inhibitory effect on neurotransmission by diminishing the chance of a successful action potential occurring at the postsynaptic cell. The reversal potential of the GABAA-mediated inhibitory postsynaptic potential (IPSP) in normal solution is −70 mV, contrasting the GABAB IPSP (-100 mV). Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3β-Androstanediol
3β-Androstanediol, also known as 5α-androstane-3β,17β-diol, and sometimes shortened in the literature to 3β-diol, is an endogenous steroid hormone and a metabolite of androgens like dehydroepiandrosterone (DHEA) and dihydrotestosterone (DHT). Biological activity 3β-Androstanediol is a selective, high-affinity agonist of the ERβ, and hence, an estrogen. In contrast to ERβ, 3β-androstanediol does not bind to the androgen receptor (AR). 3β-Androstanediol has been reported to also bind to ERα with low nanomolar affinity, with several-fold lower affinity relative to ERβ. It has approximately 3% and 7% of the affinity of estradiol at the ERα and ERβ, respectively. Unlike 3α-androstanediol, 3β-androstanediol does not bind to the GABAA receptor. 3β-Androstanediol may be the primary endogenous ligand of ERβ in the prostate gland, and as a result of activation of the ERβ, 3β-androstanediol has antiproliferative effects against prostate cancer cells. Through the ERβ, 3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pregnanolone
Pregnanolone, also known as eltanolone, is an endogenous inhibitory neurosteroid which is produced in the body from progesterone. It is closely related to allopregnanolone, which has similar properties. Biological activity Pregnanolone is a positive allosteric modulator of the GABAA receptor, as well as a negative allosteric modulator of the glycine receptor. Biological function Pregnanolone has sedative, anxiolytic, anesthetic, and anticonvulsant effects. During pregnancy, pregnanolone and allopregnanolone are involved in sedation and anesthesia of the fetus. Biochemistry Pregnanolone is synthesized from progesterone via the enzymes 5β-reductase and 3α-hydroxysteroid dehydrogenase, with 5β-dihydroprogesterone occurring as a metabolic intermediate. The elimination half-life of pregnanolone is between 0.9 and 3.5 hours. Chemistry Pregnanolone, also known as 3α,5β-tetrahydroprogesterone (3α,5β-THP) or as 5β-pregnan-3α-ol-20-one, is a naturally occurring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3β-Dihydroprogesterone
3β-Dihydroprogesterone (3β-DHP), also known as 3β-hydroxyprogesterone, or pregn-4-en-3β-ol-20-one (4-pregnenolone, δ4-pregnenolone), is an endogenous steroid. It is biosynthesized by 3β-hydroxysteroid dehydrogenase from progesterone. Unlike 3α-dihydroprogesterone (3α-DHP), 3β-DHP does not act as a positive allosteric modulator of the GABAA receptor, which is in accordance with the fact that other 3β-hydroxylated progesterone metabolites such as isopregnanolone and epipregnanolone similarly do not act as potentiators of this receptor and instead inhibit it as well as reverse the effects of potentiators like allopregnanolone. 3β-DHP has been reported to possess about the same potency as progesterone in a bioassay of progestogenic activity, whereas 3α-DHP was not assessed. See also * 5α-Dihydroprogesterone * 5β-Dihydroprogesterone * 3β-Androstanediol * Pregnenolone Pregnenolone (P5), or pregn-5-en-3β-ol-20-one, is an endogenous steroid and precursor/ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel Activator
A channel opener, also known as a channel activator, is a type of drug which facilitates ion flow through ion channels. They include the following: * Potassium channel openers * Calcium channel openers * Sodium channel openers * Chloride channel openers See also * Channel blocker A channel blocker is the biological mechanism in which a particular molecule is used to prevent the opening of ion channels in order to produce a physiological response in a cell. Channel blocking is conducted by different types of molecules, su ... Ion channel openers {{pharmacology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRPM3
Transient receptor potential cation channel subfamily M member 3 is a protein that in humans is encoded by the ''TRPM3'' gene. Function The product of this gene belongs to the family of transient receptor potential (TRP) channels. TRP channels are Ca2+ permeable non-selective cation channels that play roles in a wide variety of physiological processes, including calcium signaling, heat and cold sensation, calcium and magnesium homeostasis. TRPMs mediates sodium and calcium entry, which induces depolarization and a cytoplasmic Ca2+ signal. Alternatively spliced transcript variants encoding different isoforms have been -identified. TRPM3 was shown to be activated by the neurosteroid pregnenolone sulfate as well as the synthetic compound CIM0216. Peripheral heat sensation TRPM3 is expressed in peripheral sensory neurons of the dorsal root ganglia, and they are activated by high temperatures. Genetic deletion of TRPM3 in mice reduces sensitivity to noxious heat, as well as in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NMDA Receptor
The ''N''-methyl-D-aspartate receptor (also known as the NMDA receptor or NMDAR), is a glutamate receptor and ion channel found in neurons. The NMDA receptor is one of three types of ionotropic glutamate receptors, the other two being AMPA receptor, AMPA and kainate receptors. Depending on its subunit composition, its Ligand (biochemistry), ligands are glutamate and glycine (or D-Serine, D-serine). However, the binding of the ligands is typically not sufficient to open the channel as it may be blocked by Magnesium, Mg2+ ions which are only removed when the neuron is sufficiently depolarized. Thus, the channel acts as a “coincidence detector” and only once both of these conditions are met, the channel opens and it allows cation, positively charged ions (cations) to flow through the cell membrane. The NMDA receptor is thought to be very important for controlling synaptic plasticity and mediating learning and memory functions. The NMDA receptor is ionotropic, meaning it is a pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
