This MedLibrary.org supplementary page on Sympathomimetic agents is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
Sympathomimetic drugs are substances that mimic the effects of the catecholamines epinephrine (adrenaline), norepinephrine (noradrenaline), and/or dopamine. Such drugs are used to treat cardiac arrest, low blood pressure, or even delay premature labor, among other things.
These drugs act at the postganglionic sympathetic terminal,[1] either directly activating postsynaptic receptors, blocking breakdown and reuptake, or stimulating production and release of catecholamines.
Contents |
Mechanisms of action
The mechanisms of sympathomimetic drugs can be direct-acting, such as α-adrenergic agonists, β-adrenergic agonists, dopaminergic agonists; or indirect-acting, such as MAOIs, COMTs, release stimulants, and reuptake inhibitors.
Direct-acting
Adrenergic receptor agonists
Direct stimulation of the α- and β-adrenergic receptors can produce sympathomimetic effects. Albuterol is a very commonly used direct-acting β2-agonist. Other examples include phenylephrine, isoproterenol, and dobutamine.
Dopaminergic agonists
Stimulation of the D1 receptor by dopaminergic agonists such as fenoldopam is used intravenously to treat hypertensive crisis.
Indirect-acting
Norepinephrine transporter blockade
Classical sympathomimetic drugs are amphetamines (including MDMA), ephedrine and cocaine, which act by blocking and reversing norepinephrine transporter (NET) activity. NET is a transport protein expressed on the surface of some cells that clears noradrenaline and adrenaline from the extracellular space and into cells, terminating the signaling effects.
Inhibition of epinephrine and norepinephrine metabolism
Inhibition of norepinephrine or epinephrine metabolism can produce sympathomimetic effects. Both are mainly metabolized by the enzyme monoamine oxidase, the monoamine oxidase inhibitor (MAOI) drugs can induce such effects. COMT inhibitors can also decrease metabolism of norepinephrine and epinephrine.
Cross-reactivity
Substances like cocaine also affect dopamine, and some substances like MDMA affect serotonin.
Norepinephrine is synthesized by the body into epinephrine, causing central nervous system stimulation. Thus, all sympathomimetic amines fall into the larger group of stimulants (see psychoactive drug chart). Many of these stimulants have therepeutic use and abuse potential, can induce tolerance, and possibly physical dependence.
See also
References
External links
- MeSH Amines,+Sympathomimetic
- Sympathomimetic+amine at eMedicine Dictionary
- Sympathomimetic at eMedicine Dictionary
|
||||||||||||||||||||||||||||||||||||||
|
||||||||
|
||||||||||||||||||||||||||||
|
|||||||||||||||||||
|
||||||||||||||||||||
|
||||||||
Wikipedia content modification information:
- This page was last modified on 2 October 2008, at 19:18.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Sympathomimetic agents".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.