Sigma receptor

Jump to: navigation, search
File:Sigma opioid receptor.png
Schematic σ receptor

WikiDoc Resources for Sigma receptor

Articles

Most recent articles on Sigma receptor

Most cited articles on Sigma receptor

Review articles on Sigma receptor

Articles on Sigma receptor in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Sigma receptor

Images of Sigma receptor

Photos of Sigma receptor

Podcasts & MP3s on Sigma receptor

Videos on Sigma receptor

Evidence Based Medicine

Cochrane Collaboration on Sigma receptor

Bandolier on Sigma receptor

TRIP on Sigma receptor

Clinical Trials

Ongoing Trials on Sigma receptor at Clinical Trials.gov

Trial results on Sigma receptor

Clinical Trials on Sigma receptor at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Sigma receptor

NICE Guidance on Sigma receptor

NHS PRODIGY Guidance

FDA on Sigma receptor

CDC on Sigma receptor

Books

Books on Sigma receptor

News

Sigma receptor in the news

Be alerted to news on Sigma receptor

News trends on Sigma receptor

Commentary

Blogs on Sigma receptor

Definitions

Definitions of Sigma receptor

Patient Resources / Community

Patient resources on Sigma receptor

Discussion groups on Sigma receptor

Patient Handouts on Sigma receptor

Directions to Hospitals Treating Sigma receptor

Risk calculators and risk factors for Sigma receptor

Healthcare Provider Resources

Symptoms of Sigma receptor

Causes & Risk Factors for Sigma receptor

Diagnostic studies for Sigma receptor

Treatment of Sigma receptor

Continuing Medical Education (CME)

CME Programs on Sigma receptor

International

Sigma receptor en Espanol

Sigma receptor en Francais

Business

Sigma receptor in the Marketplace

Patents on Sigma receptor

Experimental / Informatics

List of terms related to Sigma receptor


The sigma receptors σ1 and σ2 are receptors which bind to ligands such as 4-PPBP[1], SA 4503, and siramesine.[2]

Classification

Sigma receptors were once thought to be a type of opioid receptor, because the d stereoisomers of the benzomorphan class of opioid drugs had no effects at μ, κ, and δ receptors, but reduced coughing.

However, pharmacological testing indicated that the sigma receptors were activated by drugs completely unrelated to the opioids, and their function was unrelated to the function of the opioid receptors. For example, phencyclidine (PCP), and the antipsychotic haloperidol may interact with these receptors. Neither phencyclidine nor haloperidol have any appreciable chemical similarity to the opioids.

When the σ1 receptor was isolated and cloned, it was found to have no structural similarity to the opioid receptors. At this point, they were designated as a separate class of receptors.

Functions

The functions of these receptors are poorly understood and any endogenous ligands have yet to be identified. Activation of sigma receptors by an agonist ligand may induce hallucinogenic effects and also may be responsible for the paradoxical convulsions sometimes seen in opiate overdose. Drugs known to be sigma agonists in addition to their major mechanisms of action include cocaine, heroin, PCP, fluvoxamine, methamphetamine and dextromethorphan, however the exact role of sigma receptors is difficult to establish as many sigma agonists also bind to other targets such as the κ-opioid receptor and the NMDA receptor. In animal experiments, sigma antagonists such as rimcazole were able to block convulsions from cocaine overdose. Sigma antagonists are also under investigation for use as antipsychotic medications.

Physiologic effects

Physiologic effects (what happens to the human body) when the sigma receptor is activated include dysphoria (feelings of unease), hypertonia (increased muscle tension), tachycardia (increase in heart rate), tachypnea (increase in rate of breathing), and mydriasis (increase in the size of the pupils, similar to what occurs in conditions of low light).

Recently novel σ–receptor agonists have been able to produce antidepressant effects in mice.[3]

References

  1. Yang S, Bhardwaj A, Cheng J, Alkayed NJ, Hurn PD, Kirsch JR (2007). "Sigma receptor agonists provide neuroprotection in vitro by preserving bcl-2". Anesth. Analg. 104 (5): 1179–84, tables of contents. doi:10.1213/01.ane.0000260267.71185.73. PMID 17456670.
  2. Skuza G, Rogóz Z (2006). "The synergistic effect of selective sigma receptor agonists and uncompetitive NMDA receptor antagonists in the forced swim test in rats". J. Physiol. Pharmacol. 57 (2): 217–29. PMID 16845227.
  3. Wang J, Mack AL, Coop A, Matsumoto RR (2007). "Novel sigma (sigma) receptor agonists produce antidepressant-like effects in mice". Eur Neuropsychopharmacol. 2007 (Mar 19): Epub ahead of print. doi:10.1016/j.euroneuro.2007.02.007. PMID 17376658.

External links



Linked-in.jpg