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Zaprinast
Zaprinast was an unsuccessful clinical drug candidate that was a precursor to the chemically related PDE5 inhibitors, such as sildenafil (Viagra), which successfully reached the market. It is a phosphodiesterase inhibitor, selective for the subtypes PDE5, PDE6, PDE9 and PDE11. IC50 values are 0.76, 0.15, 29.0, and 12.0 ''μ''M, respectively. Zaprinast inhibits the growth of asexual blood-stage malaria parasites ( ''P. falciparum'') ''in vitro'' with an ED50 value of 35 ''μ''M, and inhibits PfPDE1, a '' P. falciparum'' cGMP-specific phosphodiesterase, with an IC50 value of 3.8 ''μ''M. Zaprinast has also been shown to activate the orphan G-protein coupled receptor known as GPR35, both in rats and humans, and to inhibit the mitochondrial pyruvate Pyruvic acid (CH3COCOOH) is the simplest of the alpha-keto acids, with a carboxylic acid and a ketone functional group. Pyruvate, the conjugate base, CH3COCOO−, is an intermediate in several metabolic pathways throughout the cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GPR35
G protein-coupled receptor 35 also known as GPR35 is a G protein-coupled receptor which in humans is encoded by the ''GPR35'' gene. Heightened expression of GPR35 is found in immune and gastrointestinal tissues, including the crypts of Lieberkühn. Ligands Endogenous ligands Although GPR35 is still considered an orphan receptor, there have been attempts to deorphanize it by identifying endogenous molecules that can activate the receptor. All of the currently proposed ligands are either unselective towards GPR35, or they lack high potency, a characteristic feature of natural ligands. The following list includes the most prominent examples: * kynurenic acidfree fulltext * LPA species [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CGMP-specific Phosphodiesterase Type 5
Cyclic guanosine monophosphate-specific phosphodiesterase type 5 is an enzyme () from the phosphodiesterase class. It is found in various tissues, most prominently the corpus cavernosum and the retina. It has also been recently discovered to play a vital role in the cardiovascular system. The phosphodiesterase (PDE) isozymes, found in several tissues including the rod and cone photoreceptor cells of the retina, belong to a large family of cyclic nucleotide PDEs that catalyze cAMP and cGMP hydrolysis. The interest in PDEs as molecular targets of drug action has grown with the development of isozyme-selective PDE inhibitors that offer potent inhibition of selected isozymes without the side-effects attributed to nonselective inhibitors such as theophylline. Sildenafil, vardenafil, tadalafil, and avanafil are PDE5 inhibitors that are significantly more potent and selective than zaprinast and other early PDE5 inhibitors. Action of PDE5 PDE5 is an enzyme that accepts cGMP and b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDE5 Inhibitor
A phosphodiesterase type 5 inhibitor (PDE5 inhibitor) is a vasodilating drug that works by blocking the degradative action of cGMP-specific phosphodiesterase type 5 (PDE5) on cyclic GMP in the smooth muscle cells lining the blood vessels supplying various tissues. These drugs dilate the corpora cavernosa of the penis, facilitating erection with sexual stimulation, and are used in the treatment of erectile dysfunction (ED). Sildenafil was the first effective oral treatment available for ED. Because PDE5 is also present in the smooth muscle of the walls of the arterioles within the lungs, two PDE5 inhibitors, sildenafil and tadalafil, are FDA-approved for the treatment of pulmonary hypertension. As of 2019, the wider cardiovascular benefits of PDE5 inhibitors are being appreciated. Medical uses Phosphodiesterase-5 (PDE5) inhibitors such as sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra) are clinically indicated for the treatment of erectile dysfunction. Sildena ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sildenafil
Sildenafil, sold under the brand name Viagra, among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension. It is unclear if it is effective for treating sexual dysfunction in women. It is taken by mouth or by injection into a vein. Onset is typically within twenty minutes and lasts for about two hours. Common side effects include headaches, heartburn, and flushed skin. Caution is advised in those with cardiovascular disease. Rare but serious side effects include a prolonged erection (priapism) that can lead to damage to the penis, vision problems, and hearing loss. Sildenafil should not be taken by people on nitrates such as nitroglycerin (glycerin trinitrate), as this may result in a serious drop in blood pressure. Sildenafil should not be taken within four hours of taking an alpha blocker. Sildenafil acts by blocking phosphodiesterase 5 (PDE5), an enzyme that promotes breakdown of cGMP, which regulates blood flow in the pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphodiesterase Inhibitor
A phosphodiesterase inhibitor is a drug that blocks one or more of the five subtypes of the enzyme phosphodiesterase (PDE), thereby preventing the inactivation of the intracellular second messengers, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) by the respective PDE subtype(s). The ubiquitous presence of this enzyme means that non-specific inhibitors have a wide range of actions, the actions in the heart, and lungs being some of the first to find a therapeutic use. History The different forms or subtypes of phosphodiesterase were initially isolated from rat brains in the early 1970s and were soon afterward shown to be selectively inhibited in the brain and in other tissues by a variety of drugs. The potential for selective phosphodiesterase inhibitors as therapeutic agents was predicted as early as 1977 by Weiss and Hait. This prediction meanwhile has proved to be true in a variety of fields. Classification Nonselective PDE inhibitors Methyla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDE6
Photoreceptor phosphodiesterase 6 (PDE6 or PDE-6) is a protein complex family, which is highly concentrated in the retina. See also * cGMP * PDE6A * PDE6B * PDE6C * PDE6D * PDE6G Retinal rod rhodopsin-sensitive cGMP 3',5'-cyclic phosphodiesterase subunit gamma is an enzyme that in humans is encoded by the ''PDE6G'' gene. Interactions PDE6G has been shown to interact with Beta adrenergic receptor kinase G-protein-cou ... References {{Enzymes EC 3.1.4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDE9
Phosphodiesterase type 9 (PDE9) is a type of phosphodiesterase enzyme. Some inhibitors include BAY 73-6691 BAY 73-6691 is a drug developed by Bayer for the treatment of Alzheimer's disease. It was the first compound developed that acts as a phosphodiesterase inhibitor selective for the PDE9A subtype. The PDE9A enzyme is expressed primarily in the br ... and PF-04447943. References Enzymes {{enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDE11
Phosphodiesterase type 11 (PDE11) is a type of phosphodiesterase enzyme. An inhibitor Inhibitor or inhibition may refer to: In biology * Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity * Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotra ... is BC11-38. References Enzymes {{enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IC50
The half maximal inhibitory concentration (IC50) is a measure of the potency of a substance in inhibiting a specific biological or biochemical function. IC50 is a quantitative measure that indicates how much of a particular inhibitory substance (e.g. drug) is needed to inhibit, ''in vitro'', a given biological process or biological component by 50%. The biological component could be an enzyme, cell, cell receptor or microorganism. IC50 values are typically expressed as molar concentration. IC50 is commonly used as a measure of antagonist drug potency in pharmacological research. IC50 is comparable to other measures of potency, such as EC50 for excitatory drugs. EC50 represents the dose or plasma concentration required for obtaining 50% of a maximum effect ''in vivo''. IC50 can be determined with functional assays or with competition binding assays. Sometimes, IC50 values are converted to the pIC50 scale. :\ce = -\log_ \ce Due to the minus sign, higher values of pIC50 indica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malaria
Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. Symptoms usually begin ten to fifteen days after being bitten by an infected mosquito. If not properly treated, people may have recurrences of the disease months later. In those who have recently survived an infection, reinfection usually causes milder symptoms. This partial resistance disappears over months to years if the person has no continuing exposure to malaria. Malaria is caused by single-celled microorganisms of the ''Plasmodium'' group. It is spread exclusively through bites of infected ''Anopheles'' mosquitoes. The mosquito bite introduces the parasites from the mosquito's saliva into a person's blood. The parasites travel to the liver where they mature and reproduce. Five species of ''Plasmodium'' can infect and be spread by h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmodium Falciparum
''Plasmodium falciparum'' is a Unicellular organism, unicellular protozoan parasite of humans, and the deadliest species of ''Plasmodium'' that causes malaria in humans. The parasite is transmitted through the bite of a female ''Anopheles'' mosquito and causes the disease's most dangerous form, falciparum malaria. It is responsible for around 50% of all malaria cases. ''P. falciparum'' is therefore regarded as the deadliest parasite in humans. It is also associated with the development of blood cancer (Burkitt's lymphoma) and is classified as a List of IARC Group 2A carcinogens, Group 2A (probable) carcinogen. The species originated from the malarial parasite ''Laverania'' found in gorillas, around 10,000 years ago. Alphonse Laveran was the first to identify the parasite in 1880, and named it ''Oscillaria malariae''. Ronald Ross discovered its transmission by mosquito in 1897. Giovanni Battista Grassi elucidated the complete transmission from a female Anopheles, anopheline mosquit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ED-50
In pharmacology, an effective dose (ED) or effective concentration (EC) is a dose or concentration of a drug that produces a biological response. The term effective dose is used when measurements are taken ''in vivo,'' while the term effective concentration is used when the measurements are taken ''in vitro''. It has been stated that any substance can be toxic at a high enough dose. This concept was exemplified in 2007 when a California woman died of water intoxication in a contest sanctioned by a radio station. The line between efficacy and toxicity is dependent upon the particular patient, although the dose administered by a physician should fall into the predetermined therapeutic window of the drug. The importance of determining the therapeutic range of a drug cannot be overstated. This is generally defined by the range between the minimum effective dose (MED) and the maximum tolerated dose (MTD). The MED is defined as the lowest dose level of a pharmaceutical product that p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
