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Vasopressin Receptor Antagonist
A vasopressin receptor antagonist (VRA) is an agent that interferes with action at the vasopressin receptors. Most commonly VRAs are used in the treatment of hyponatremia, especially in patients with congestive heart failure, liver cirrhosis or SIADH. Types Vaptans The "vaptan" drugs act by directly blocking the action of vasopressin at its receptors ( V1A, V1B and V2). These receptors have a variety of functions, with the V1A and V2 receptors are expressed peripherally and involved in the modulation of blood pressure and kidney function respectively, while the V1A and V1B receptors are expressed in the central nervous system. V1A is expressed in many regions of the brain, and has been linked to a variety of social behaviors in humans and animals. The vaptan class of drugs contains a number of compounds with varying selectivity, several of which are either already in clinical use or in clinical trials as of 2009. ;Unselective (mixed V1A/V2) * Conivaptan ;V1A selective (V1R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasopressin Receptor
The actions of vasopressin are mediated by stimulation of tissue-specific G protein-coupled receptors (GPCRs) called vasopressin receptors that are classified into the V1 (V1A), V2, and V3 (V1B) receptor subtypes. These three subtypes differ in localization, function and signal transduction mechanisms. Subtypes There are three subtypes of vasopressin receptor: V1A (V1), V1B (V3) and V2. V1 receptor V1 receptors (V1Rs) are found in high density on vascular smooth muscle and cause vasoconstriction by an increase in intracellular calcium via the phosphatidyl–inositol-bisphosphate cascade. Cardiac myocytes also possess V1R. Additionally V1R are located in brain, testis, superior cervical ganglion, liver, blood vessels, and renal medulla. V1R is present on platelets, which upon stimulation induces an increase in intracellular calcium, facilitating thrombosis. Studies have indicated that due to polymorphism of platelet V1R there is significant heterogeneity in the ag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syndrome Of Inappropriate Antidiuretic Hormone
Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is characterized by excessive unsuppressible release of antidiuretic hormone (ADH) either from the posterior pituitary gland, or an abnormal non-pituitary source. Unsuppressed ADH causes an unrelenting increase in solute-free water being returned by the tubules of the kidney to the venous circulation. The causes of SIADH are grouped into six categories: 1) central nervous system diseases that directly stimulate the hypothalamus, the site of control of ADH secretion; 2) various cancers that synthesize and secrete ectopic ADH; 3) various lung diseases; 4) numerous drugs that chemically stimulate the hypothalamus; 5) inherited mutations; and 6) miscellaneous largely transient conditions. ADH is derived from a preprohormone precursor that is synthesized in cells in the hypothalamus and stored in vesicles in the posterior pituitary. ''Appropriate'' ADH secretion is regulated by osmoreceptors on the hypothalamic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclic AMP
Cyclic adenosine monophosphate (cAMP, cyclic AMP, or 3',5'-cyclic adenosine monophosphate) is a second messenger important in many biological processes. cAMP is a derivative of adenosine triphosphate (ATP) and used for intracellular signal transduction in many different organisms, conveying the cAMP-dependent pathway. History Earl Sutherland of Vanderbilt University won a Nobel Prize in Physiology or Medicine in 1971 "for his discoveries concerning the mechanisms of the action of hormones", especially epinephrine, via second messengers (such as cyclic adenosine monophosphate, cyclic AMP). Synthesis Cyclic AMP is synthesized from ATP by adenylate cyclase located on the inner side of the plasma membrane and anchored at various locations in the interior of the cell. Adenylate cyclase is ''activated'' by a range of signaling molecules through the activation of adenylate cyclase stimulatory G ( Gs)-protein-coupled receptors. Adenylate cyclase is ''inhibited'' by agonists of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forced Diuresis
Diuresis () is increased urination (polyuria) or, in the related word senses more often intended, the physiological process that produces such an increase or the administration of medications to encourage that process. It involves extra urine production in the kidneys as part of the body's homeostatic maintenance of fluid balance. In healthy people, the drinking of extra water produces mild diuresis to maintain the body water balance. Many people with health issues, such as heart failure and kidney failure, need diuretic medications to help their kidneys deal with the fluid overload of edema. These drugs promote water loss via urine production. The concentrations of electrolytes in the blood are closely linked to fluid balance, so any action or problem involving fluid intake or output (such as polydipsia, polyuria, diarrhea, heat exhaustion, starting or changing doses of diuretics, and others) can require management of electrolytes, whether through self-care in mild cases or with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ascites
Ascites is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdominal size, increased weight, abdominal discomfort, and shortness of breath. Complications can include spontaneous bacterial peritonitis. In the developed world, the most common cause is liver cirrhosis. Other causes include cancer, heart failure, tuberculosis, pancreatitis, and blockage of the hepatic vein. In cirrhosis, the underlying mechanism involves high blood pressure in the portal system and dysfunction of blood vessels. Diagnosis is typically based on an examination together with ultrasound or a CT scan. Testing the fluid can help in determining the underlying cause. Treatment often involves a low-salt diet, medication such as diuretics, and draining the fluid. A transjugular intrahepatic portosystemic shunt (TIPS) may be placed but is associated with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lixivaptan
Lixivaptan (VPA-985) is an orally-active, non-peptide, selective vasopressin 2 receptor antagonist being developed as an investigational drug by Palladio Biosciences, Inc. (Palladio), a subsidiary of Centessa Pharmaceuticals plc. , lixivaptan is in Phase III clinical development for the treatment of Autosomal dominant polycystic kidney disease (ADPKD), the most common form of polycystic kidney disease. The U.S. Food and Drug Administration (FDA) has granted orphan drug designation to lixivaptan for the treatment of ADPKD. Mechanism of action Lixivaptan is a potent, non-peptide, selective vasopressin receptor antagonist. It is a member of the vaptan class of drugs. Hyponatremia V2 receptor antagonists inhibit the binding of arginine vasopressin to vasopressin receptor 2 (V2R) in kidney tubular epithelial cells, thereby having a net effect of aquaresis, or electrolyte free water excretion. This property of vaptans explains their use as therapies to treat euvolemic and hypervol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tolvaptan
Tolvaptan, sold under the brand name Samsca among others, is an aquaretic drug that functions as a selective, competitive vasopressin receptor 2 (V2) antagonist used to treat hyponatremia (low blood sodium levels) associated with congestive heart failure, cirrhosis, and the syndrome of inappropriate antidiuretic hormone (SIADH). Tolvaptan was approved by the U.S. Food and Drug Administration (FDA) on May 19, 2009, and is sold by Otsuka Pharmaceutical Co. under the trade name Samsca. Tolvaptan, as Jynarque, was granted approval for medical use in the United States in April 2018. The U.S. Food and Drug Administration (FDA) granted tolvaptan a fast track designation for clinical trials investigating its use for the treatment of polycystic kidney disease. The FDA granted Jynarque an orphan drug designation in April 2012, for the treatment of autosomal dominant polycystic kidney disease. Tolvaptan is available as a generic medication. Medical uses Tolvaptan (Samsca) is indic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conivaptan
Conivaptan, sold under the brand name Vaprisol, is a non-peptide inhibitor of the receptor for anti-diuretic hormone, also called vasopressin. It was approved in 2004 for hyponatremia (low blood sodium levels). The compound was discovered by Astellas and marked in 2006. The drug is now marketed by Cumberland Pharmaceuticals, Inc. Conivaptan inhibits two of the three subtypes of the vasopressin receptor ( V1a and V2). Effectively, it causes iatrogenic nephrogenic diabetes insipidus. Conivaptan has not been approved by the American Food and Drug Administration for the treatment of decompensated congestive heart failure. However, in theory, vasopressin receptor antagonism would be particularly useful in this setting, and an initial study shows that it has some promise. Medical uses Conivaptan is most commonly used in the hospital in cases of euvolemic and hypervolemic hyponatremia, conditions where the sodium level in the blood falls significantly below normal. In the United S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquaresis
An aquaretic is a novel class of drug that is used to promote aquaresis, the excretion of water without electrolyte loss. Strictly speaking, aquaretics are not diuretics but are sometimes classified as such. Aquaresis is preferable to diuresis in the treatment of hyponatremia. Pharmacokinetics Aquaretics increase urine output without increasing sodium and chloride excretion, thus causing an increase in urine whilst retaining electrolytes. Examples A number of herbal medicines are classified as aquaretics, for example common horsetail or common nettle leaves. Synthetic aquaretics are vasopressin receptor antagonists and include conivaptan, tolvaptan, demeclocycline, and mozavaptan (OPC-31260), as well as lithium. Conivaptan hydrochloride and tolvaptan have been approved by the FDA for treating syndrome of inappropriate antidiuretic hormone Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is characterized by excessive unsuppressible release of antidiuretic horm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypervolemia
Hypervolemia, also known as fluid overload, is the medical condition where there is too much fluid in the blood. The opposite condition is hypovolemia, which is too little fluid volume in the blood. Fluid volume excess in the intravascular compartment occurs due to an increase in total body sodium content and a consequent increase in extracellular body water. The mechanism usually stems from compromised regulatory mechanisms for sodium handling as seen in congestive heart failure (CHF), kidney failure, and liver failure. It may also be caused by excessive intake of sodium from foods, intravenous (IV) solutions and blood transfusions, medications, or diagnostic contrast dyes. Treatment typically includes administration of diuretics and limit the intake of water, fluids, sodium, and salt. Signs and symptoms The excess fluid, primarily salt and water, builds up in various locations in the body and leads to an increase in weight, swelling in the legs and arms (peripheral edema), and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euvolemia
Fluid balance is an aspect of the homeostasis of organisms in which the amount of water in the organism needs to be controlled, via osmoregulation and behavior, such that the concentrations of electrolytes (salts in solution) in the various body fluids are kept within healthy ranges. The core principle of fluid balance is that the amount of water lost from the body must equal the amount of water taken in; for example, in humans, the output (via respiration, perspiration, urination, defecation, and expectoration) must equal the input (via eating and drinking, or by parenteral intake). Euvolemia is the state of normal body fluid volume, including blood volume, interstitial fluid volume, and intracellular fluid volume; hypovolemia and hypervolemia are imbalances. Water is necessary for all life on Earth. Humans can survive for 4 to 6 weeks without food but only for a few days without water. Profuse sweating can increase the need for electrolyte replacement. Water-electrolyte imba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium Carbonate
Lithium carbonate is an inorganic compound, the lithium salt of carbonate with the formula . This white salt is widely used in the processing of metal oxides. It is listed on the World Health Organization's List of Essential Medicines because it can be used as a treatment for mood disorders such as bipolar disorder. Uses Lithium carbonate is an important industrial chemical. Its main use is as a precursor for compounds used in lithium-ion batteries. Glasses derived from lithium carbonate are useful in ovenware. Lithium carbonate is a common ingredient in both low-fire and high-fire ceramic glaze. It forms low-melting fluxes with silica and other materials. Its alkaline properties are conducive to changing the state of metal oxide colorants in glaze, particularly red iron oxide (). Cement sets more rapidly when prepared with lithium carbonate, and is useful for tile adhesives. When added to aluminium trifluoride, it forms LiF which gives a superior electrolyte for the processi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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