SIGMA

Pronunciation (US):

(GB):

IPA (US):

 Dictionary entry overview: What does sigma mean? 

• SIGMA (noun)
  The noun SIGMA has 1 sense:

1. the 18th letter of the Greek alphabet

  Familiarity information: SIGMA used as a noun is very rare.

 Dictionary entry details 

• SIGMA (noun)

Sense 1

Meaning:

The 18th letter of the Greek alphabet

Classified under:

Nouns denoting communicative processes and contents

Hypernyms ("sigma" is a kind of...):

alphabetic character; letter; letter of the alphabet (the conventional characters of the alphabet used to represent speech)

Holonyms ("sigma" is a member of...):

Greek alphabet (the alphabet used by ancient Greeks)

 Context examples 

Sigma-2 receptors, expressed in a variety of normal healthy tissues such as liver, kidneys, endocrine glands, and in the central nervous system, may be overexpressed in tumor cells.

(Fluorine F 18 ISO-1, NCI Thesaurus)

To allow cell-cycle progression, estrogens stimulate production of Efp, which binds and ubiquinates 14-3-3s sigma. 14-3-3s marked with ubiquitin chains is recognized and destroyed by the proteasome.

(EFP Cell Cycle Pathway, NCI Thesaurus/BIOCARTA)

Noscapine exerts its antitussive effects through the activation of sigma opioid receptors.

(Noscapine, NCI Thesaurus)

This agent crosses the blood-brain-barrier and activates sigma opioid receptors on the cough center in the central nervous system, thereby suppressing the cough reflex.

(Dextromethorphan, NCI Thesaurus)

The sigma‑1 receptor is a very small protein present in neurons, and is capable of modulating the action of opioid receptors.

(Scientists make white blood cells to alleviate pain, instead of producing it, during tissue inflammation, University of Granada)

Although its mechanism of action is not well understood, ketamine appears to non-competitively block N-methyl-D-aspartate (NMDA) receptors and agonistically bind to and activate opioid mu and sigma receptors, thereby reducing pain perception, inducing sedation, and producing dissociative anesthesia.

(Intranasal Ketamine, NCI Thesaurus)

Although its mechanism of action is not well understood, ketamine appears to non-competitively block N-methyl-D-aspartate (NMDA) receptors and may interact with opioid mu receptors and sigma receptors, thereby reducing pain perception, inducing sedation, and producing dissociative anesthesia.

(Ketamine hydrochloride, NCI Thesaurus)

Upon administration, fluorine [F18]ISO-1 binds to sigma-2 receptors, located on tumor cells, allowing visualization of sigma-2 receptor-expressing tumor cells with positron emission tomography (PET).

(Fluorine F 18 ISO-1, NCI Thesaurus)

A study led by scientists from the University of Granada (UGR) has discovered that sigma‑1 receptor blockers are capable of increasing the effect of endogenous opioid peptides produced by leukocytes, so that these cells relieve pain instead of producing it when they are in the inflamed tissue.

(Scientists make white blood cells to alleviate pain, instead of producing it, during tissue inflammation, University of Granada)

Researchers at the University of Granada lead a novel study in mice that shows that sigma‑1 receptor blockers cause white blood cells or leukocytes to relieve the pain felt when a tissue is inflamed.

(Scientists make white blood cells to alleviate pain, instead of producing it, during tissue inflammation, University of Granada)