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Adrenergic Alpha-agonist
Alpha-adrenergic agonists are a class of sympathomimetic agents that selectively stimulates alpha adrenergic receptors. The alpha-adrenergic receptor has two subclasses α1 and α2. Alpha 2 receptors are associated with sympatholytic properties. Alpha-adrenergic agonists have the opposite function of alpha blockers. Alpha adrenoreceptor ligands mimic the action of epinephrine and norepinephrine signaling in the heart, smooth muscle and central nervous system, with norepinephrine being the highest affinity. The activation of α1 stimulates the membrane bound enzyme phospholipase C, and activation of α2 inhibits the enzyme adenylate cyclase. Inactivation of adenylate cyclase in turn leads to the inactivation of the secondary messenger cyclic adenosine monophosphate and induces smooth muscle and blood vessel constriction. Classes Although complete selectivity between receptor agonism is rarely achieved, some agents have partial selectivity. NB: the inclusion of a drug in each c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agonist
An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an Receptor antagonist, antagonist blocks the action of the agonist, while an inverse agonist causes an action opposite to that of the agonist. Etymology The word originates from the Ancient Greek, Greek word (''agōnistēs''), "contestant; champion; rival" < (''agōn''), "contest, combat; exertion, struggle" < (''agō''), "I lead, lead towards, conduct; drive." Types of agonists Receptor (biochemistry), Receptors can be activated by either endogenous agonists (such as hormones and neurotransmitters) or exogenous agonists (such as medication, drugs), resulting in a biological response. A physiological agonism an ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclic Adenosine Monophosphate
Cyclic adenosine monophosphate (cAMP, cyclic AMP, or 3',5'-cyclic adenosine monophosphate) is a second messenger, or cellular signal occurring within cells, that is 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 The synthesis of cAMP is stimulated by trophic hormones that bind to receptors on the cell surface. cAMP levels reach maximal levels within minutes and decrease gradually over an hour in cultured cells. Cyclic AMP is synthesized from ATP by adenylate cyclase located on the inner side of the plasma membrane and anchored at v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcohol Withdrawal
Alcohol withdrawal syndrome (AWS) is a set of symptoms that can occur following a reduction in or cessation of alcohol use after a period of excessive use. Symptoms typically include anxiety, shakiness, sweating, vomiting, fast heart rate, and a mild fever. More severe symptoms may include seizures, and delirium tremens (DTs); which can be fatal in untreated patients. Symptoms start at around 6 hours after the last drink. Peak incidence of seizures occurs at 24 to 36 hours and peak incidence of delirium tremens is at 48 to 72 hours. Alcohol withdrawal may occur in those who are alcohol dependent. This may occur following a planned or unplanned decrease in alcohol intake. The underlying mechanism involves a decreased responsiveness of GABA receptors in the brain. The withdrawal process is typically followed using the Clinical Institute Withdrawal Assessment for Alcohol scale (CIWA-Ar). The typical treatment of alcohol withdrawal is with benzodiazepines such as chlordiazep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opiate
An opiate is an alkaloid substance derived from opium (or poppy straw). It differs from the similar term ''opioid'' in that the latter is used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain (including antagonists). Opiates are alkaloid compounds naturally found in the opium poppy plant ''Papaver somniferum''. The psychoactive compounds found in the opium plant include morphine, codeine, and thebaine. Opiates have long been used for a variety of medical conditions, with evidence of opiate trade and use for pain relief as early as the eighth century AD. Most opiates are considered drugs with moderate to high abuse potential and are listed on various "Substance-Control Schedules" under the Uniform Controlled Substances Act of the United States of America. In 2014, between 13 and 20 million people used opioids recreationally, representing 0.3% to 0.4% of the global population between the ages of 15 and 65. According to the CDC, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedative
A sedative or tranquilliser is a substance that induces sedation by reducing irritability or Psychomotor agitation, excitement. They are central nervous system (CNS) Depressant, depressants and interact with brain activity, causing its deceleration. Various kinds of sedatives can be distinguished, but the majority of them affect the neurotransmitter Gamma-Aminobutyric acid, gamma-aminobutyric acid (GABA). Most sedatives produce relaxing effects by increasing GABA activity. This group is related to hypnotics. The term ''sedative'' describes drugs that serve to calm or Anxiolytic, relieve anxiety, whereas the term ''hypnotic'' describes drugs whose main purpose is to initiate, sustain, or lengthen sleep. Because these two functions frequently overlap, and because drugs in this class generally produce dose-dependent effects (ranging from anxiolysis to loss of consciousness), they are often referred to collectively as ''sedative–hypnotic'' drugs. Terminology There is some overlap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antihypertensive
Antihypertensives are a class of drugs that are used to treat hypertension (high blood pressure). Antihypertensive therapy seeks to prevent the complications of high blood pressure, such as stroke, heart failure, kidney failure and myocardial infarction. Evidence suggests that a reduction of blood pressure by 5 mmHg can decrease the risk of stroke by 34% and of ischaemic heart disease by 21%. It can reduce the likelihood of dementia, heart failure, and mortality from cardiovascular disease. There are many classes of antihypertensives, which lower blood pressure by different means. Among the most important and most widely used medications are thiazide diuretics, calcium channel blockers, angiotensin-converting enzyme inhibitors (ACE inhibitors), angiotensin II receptor blockers or antagonists (ARBs), and beta blockers. Which type of medication to use initially for hypertension has been the subject of several large studies and resulting national guidelines. The fundamental ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenylyl Cyclase
Adenylate cyclase (EC 4.6.1.1, also commonly known as adenyl cyclase and adenylyl cyclase, abbreviated AC) is an enzyme with systematic name ATP diphosphate-lyase (cyclizing; 3′,5′-cyclic-AMP-forming). It catalyzes the following reaction: :ATP = 3′,5′-cyclic AMP + diphosphate It has key regulatory roles in essentially all Cell (biology), cells. It is the most Polyphyly, polyphyletic known enzyme: six distinct classes have been described, all catalysis, catalyzing the same reaction but representing unrelated gene Gene family, families with no known Sequence homology, sequence or structural homology. The best known class of adenylyl cyclases is class III or AC-III (Roman numerals are used for classes). AC-III occurs widely in eukaryotes and has important roles in many human Tissue (biology), tissues. All classes of adenylyl cyclase Catalysis, catalyse the conversion of adenosine triphosphate (ATP) to cyclic adenosine monophosphate, 3',5'-cyclic AMP (cAMP) and pyrophosphate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-2 Receptor
The alpha-2 (α2) adrenergic receptor (or adrenoceptor) is a G protein-coupled receptor (GPCR) associated with the Gi heterotrimeric G-protein. It consists of three highly homologous subtypes, including α2A-, α2B-, and α2C-adrenergic. Some species other than humans express a fourth α2D-adrenergic receptor as well. Catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) signal through the α2-adrenergic receptor in the central and peripheral nervous systems. Cellular localization The α2A adrenergic receptor is localised in the following central nervous system (CNS) structures: * Brainstem (especially the locus coeruleus as presynaptic & somatodendritic autoreceptor ) * Midbrain * Hypothalamus * Olfactory system * Hippocampus * Spinal cord * Cerebral cortex * Cerebellum * Septum Whereas the α2B adrenergic receptor is localised in the following CNS structures: * Thalamus * Pyramidal layer of the hippocampus * Cerebellar Purkinje layer and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amidephrine
Amidephrine (), or amidefrine, sold under the brand name Fentrinol among others, is a selective α1-adrenergic receptor agonist which is described as an adrenergic or sympathomimetic, vasoconstrictor, and topical nasal decongestant used to treat allergic rhinitis. It is used as the mesylate salt, which has the generic names ''amidefrine mesilate'' () and ''amidephrine mesylate'' (). The drug is a substituted phenethylamine derivative and is also known as 3-methylsulfonamidyl-β-hydroxy-N-methylphenethylamine. As of 2000, it remained marketed only in Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust .... References Alpha-1 adrenergic receptor agonists Decongestants Phenylethanolamines Sympathomimetics Sulfonamides Vasoconstrictors {{Cardiovascular-drug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenylephrine
Phenylephrine, sold under the brand names Neosynephrine and Sudafed PE among others, is a medication used as a decongestant for uncomplicated nasal congestion in the form of a nasal spray or oral tablet, to dilate the pupil, to increase blood pressure given intravenously in cases of low blood pressure, and to relieve hemorrhoids as a suppository. It can also be applied to the skin. Common side effects when taken by mouth or injected include nausea, vomiting, headache, and anxiety. Use on hemorrhoids is generally well tolerated. Severe side effects may include a slow heart rate, intestinal ischemia, chest pain, kidney failure, and tissue death at the site of injection. It is unclear whether its use during pregnancy and breastfeeding is safe. Phenylephrine is a selective α1-adrenergic receptor agonist with minimal to no β-adrenergic receptor agonist activity or induction of norepinephrine release. It causes constriction of both arteries and veins. Phenylephrine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metaraminol
Metaraminol, also known as metaradrine and sold under the brand name Aramine among others, is a sympathomimetic medication which is used in the prevention and treatment of hypotension (low blood pressure), particularly as a complication of anesthesia. It is given by intramuscular or intravenous administration. Side effects of metaraminol include reflex bradycardia among others. Metaraminol is a norepinephrine releasing agent and at high doses a α1-adrenergic receptor agonist with some β-adrenergic effect. It is a substituted amphetamine and is closely related to phenylpropanolamine, ephedrine, and oxilofrine. Metaraminol was approved for medical use in the United States in September 1954. Medical uses Metaraminol is given intravenously as either a bolus (often 0.5–1 mg doses) or as an infusion, usually via peripheral intravenous access. Metaraminol is commonly available as 10 mg in 1 mL, that requires dilution prior to administration (often made ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Midodrine
Midodrine, sold under the brand names ProAmatine and Orvaten among others, is an antihypotensive medication used to treat orthostatic hypotension (low blood pressure when standing) and urinary incontinence. It is taken oral administration, by mouth. Side effects of midodrine include hypertension (high blood pressure), paresthesia, pruritus, itching, goosebumps, chills, urinary urgency, urinary retention, and urinary frequency. Midodrine is a prodrug of its active metabolite desglymidodrine. This metabolite acts as a binding selectivity, selective agonist of the alpha-1 adrenergic receptor, α1-adrenergic receptor. This in turn results in vasoconstriction and increased blood pressure. Midodrine was discovered by 1971 and was introduced for medical use in the United States in 1996. Medical uses Midodrine is indicated for the treatment of symptomatic orthostatic hypotension. It can reduce dizziness and faints by about a third, but can be limited by troublesome goose bumps, prur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
