関: adrenergic、adrenergic agent、adrenergic agonist、adrenergic drug、adrenergic receptor agonist

WordNet

drug that has the effects of epinephrine (同)adrenergic_drug
relating to epinephrine (its release or action) (同)sympathomimetic

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/03/09 18:06:15」(JST)

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An adrenergic agonist is a drug that stimulates a response from the adrenergic receptors. The five main categories of adrenergic receptors are: α₁, α₂, β₁, β₂, and β₃, although there are more subtypes, and agonists vary in specificity between these receptors, and may be classified respectively. However, there are also other mechanisms of adrenergic agonism. Epinephrine and norepinephrine are endogenous and broad-spectrum. More selective agonists are more useful in pharmacology.

An adrenergic agent is a drug, or other substance, which has effects similar to, or the same as, epinephrine (adrenaline). Thus, it is a kind of sympathomimetic agent. Alternatively, it may refer to something which is susceptible to epinephrine, or similar substances, such as a biological receptor (specifically, the adrenergic receptors).

Receptors

Directly acting adrenergic agonists act on adrenergic receptors. All adrenergic receptors are G-protein coupled, activating signal transduction pathways. The G-protein receptor can affect the function of adenylate cyclase or phospholipase C, an agonist of the receptor will upregulate the effects on the downstream pathway (it will not necessarily upregulate the pathway itself).

The receptors are broadly grouped into α and β receptors. There are two subclasses of α-receptor - α1 and α2 which are further subdivided into α1A, α1B, α1D, α2A, α2B and α2C. The α2C receptor has been reclassed from α1C, due to its greater homology with the α2 class, giving rise to the somewhat confusing nomenclature. The β receptors are divided into β1, β2 and β3. The receptors are classed physiologically, though pharmacological selectivity for receptor subtypes exists and is important in the clinical application of adrenergic agonists (and, indeed, antagonists).

From an overall perspective - α1 receptors activate phospholipase C (via G_q), increasing the activity of protein kinase C (PKC). α2 receptors inhibit adenylate cyclase (via G_i), decreasing the activity of protein kinase A (PKA). β receptors activate adenylate cyclase (via G_s), thus increasing the activity of PKA. Agonists of each class of receptor elicit these downstream responses.^[1]

Uptake and storage

Indirectly acting adrenergic agonists affect the uptake and storage mechanisms involved in adrenergic signalling.

Two uptake mechanisms exist for terminating the action of adrenergic catecholamines - uptake 1 and uptake 2. Uptake 1 occurs at the presynaptic nerve terminal to remove the neurotransmitter from the synapse. Uptake two occurs at postsynaptic and peripheral cells to prevent the neurotransmitter from diffusing laterally.

There is also enzymatic degradation of the catecholamines by two main enzymes - monoamine oxidase and catechol-o-methyl transferase. Respectively, these enzymes oxidise monoamines (including catecholamines) and methylate the hydroxal groups of the phenyl moiety of catecholamines. These enzymes can be targeted pharmacologically. Inhibitors of these enzymes act as indirect agonists of adrenergic receptors as they prolong the action of catecholamines at the receptors.^[2]

Structure–activity relationship

In general, a primary or secondary aliphatic amine separated by 2 carbons from a substituted benzene ring is minimally required for high agonist activity.^[3]

Mechanisms

A great number of drugs are available which can affect adrenergic receptors. Each drug has its own receptor specificity giving it a unique pharmacological effect. Other drugs affect the uptake and storage mechanisms of adrenergic catecholamines, prolonging their action. The following headings provide some useful examples to illustrate the various ways in which drugs can enhance the effects of adrenergic receptors.^[4]^[5]^[6]

Direct action

These drugs act directly on one or more adrenergic receptors. According to receptor selectivity they are two types -

-Non-selective : drugs act one or more receptors; these are: Adrenaline (almost all adrenergic receptors), Nor-adrenaline (acts on α1, α2 & β1), Isoprenaline (acts on β1, β2 & β3), Dopamine (acts on α1, α2, β1, D1 & D2)

-Selective: drugs which act on a single receptor only; these are further classified into α selective & β selective. α1 selective: Phenylephrine, Methoxamine, Midodrine, Oxymetazoline α2 selective: α-Methyl dopa, clonidine

β1 selective: Dobutamine β2 selective: Salbutamol, Albuterol, Terbutaline, Salmeterol, Formoterol, Pirbuterol.

Indirect action

(agents that increase neurotransmission in endogenous chemicals in this case Epinephrine and Norepinephrine)

Amphetamines
Cocaine
Methylenedioxymethamphetamine (MDMA)
Tyramine
Nicotine
Caffeine
Methylphenidate

Mixed action

Ephedrine
Pseudoephedrine

References

^ Siegel, George J; et al. (2006). Basic Neurochemistry 7e. Elsevier.
^ Rang, H.P.; et al. (2003). Pharmacology. Churchill Livingstone.
^ Medicinal Chemistry of Adrenergics and Cholinergics
^ Laurence Pharmacology 9th edition , page 450
^ Katzung Pharmacology 12th edition page 131-133
^ Lippincott's Pharmacology 5th edition page 69-85

External links

Virtual Chembook article on adrenergic drugs
adrenergic agonists at the US National Library of Medicine Medical Subject Headings (MeSH)

English Journal

Effect of propranolol on the treatment of infantile hemangiomas: a single tertiary center 3-year experience.

Park YW1, Yeom KB, Choi JW, Kim DY, Shin H, Kim KH.
The Journal of dermatological treatment.J Dermatolog Treat.2014 Oct;25(5):391-5. doi: 10.3109/09546634.2012.761667. Epub 2013 Feb 24.
BACKGROUND: Propranolol has recently become a successful first-line therapy in the treatment of infantile hemangiomas (IHs).OBJECTIVE: To evaluate and analyze the authors' experience of propranolol treatment for IHs.METHODS: A retrospective, observational study was conducted. Medical records were re
PMID 23273264

Adverse effects of propranolol treatment for infantile hemangiomas in China.

Jian D1, Chen X, Babajee K, Su J, Li J, Hu X, Xie H, Li J.
The Journal of dermatological treatment.J Dermatolog Treat.2014 Oct;25(5):388-90. doi: 10.3109/09546634.2012.755249. Epub 2013 Feb 24.
OBJECTIVES: The β-blocker propranolol was discovered to be highly effective for the treatment of infantile hemangiomas (IHs), since 2008. Although some side effects have been reported earlier, no serious side effects of its use have been reported so far in Asia, especially in China. To determine th
PMID 23216314

α-Adrenergic Blockers for the Treatment of Lower-Urinary-Tract Symptoms and Dysfunction in Women.

Boyd K1, Hilas O.
The Annals of pharmacotherapy.Ann Pharmacother.2014 Jun;48(6):711-22. doi: 10.1177/1060028014524174. Epub 2014 Mar 10.
OBJECTIVE: To evaluate the efficacy and safety of α-adrenergic blockers in the treatment of female lower-urinary-tract symptoms and dysfunction.DATA SOURCES: Literature searches were conducted using EMBASE (1974 to January 2014), International Pharmaceutical Abstracts (1970 to January 2014), and ME
PMID 24615630

Japanese Journal

神経因性膀胱における排尿筋外尿道括約筋協調不全の検討 : 第2報 :radical TUR-Pの影響及びα交感神経刺激剤負荷による反応

信野祐一郎
日本泌尿器科學會雜誌 80(10), 1443-1450, 1989-10-20
膀胱内圧-外尿道括約筋筋電図同時測定による排尿筋括約筋協調不全(DSD)のType分類と運動単位レベルでの解析の有用性につき第1報において報告した.今回,根治的経尿道的前立腺切除術(radical TUR-P)前後に同様の検討を行い比較し,その影響を述べると共にα交感神経刺激剤負荷による括約筋筋電図上の運動単位レベルでの反応についても報告した.Radical TUR-Pは18例において施行され,3 …
NAID 110003083106

A preadipocytes clonal lines from mouse brown adipose tissues. Short-and long-term responses to insulin and β-adrenergics

FOREST C.
Exp. Cell Res. 168, 218-232, 1987
NAID 80003244913

逆行性尿道抵抗に関する実験的研究

由良守司
泌尿器科紀要 26(11), p1365-1372, 1980-11-00
… In RUR the effect of alpha-adrenergics was more dominant than parasympathetics. …
NAID 120002259777

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リンク元	「アドレナリン受容体刺激薬」「adrenergic agonist」「adrenergic drug」「adrenergic receptor agonist」「adrenergic agent」
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