Carrageenan and Fos

While reading the article outlining the antinociceptive and anti-inflammatory effects of bee venom, I realized I had no idea what carrageenan or Fos were. These were both key components of the paper and so I decided to define both terms as best I could in order to clarify for any other uniformed people like myself. :)

Carrageenans are a group of substances composed of linear sulphated polysaccharides extracted from red seaweed. This group of items is utilized in many varying fields. One use of carrageenan is as a thickening, gelatin like substance in many foods. There are three main commercial classes of carrageen, which include the lota gels, kappa gels, and lambda gels. This latter type of carrageen forms a gel when mixed with proteins, and is also the type of carrageen used in the experiments regarding the anti-inflammatory properties of bee venom. Lambda carrageenan solution of 1-2% causes inflammation, swelling, and pain in when injected into animal experimental models.

I had a hard time finding a definition for Fos. What I did find is that Fos is a protein found within the body that is usually at a low concentrations until a neuron is activated by an external stimulus, such as pain. I also found that Fos expression can increase with other factors as well, such as metabolic changes. I am actually wondering if anyone can give me a clearer definition on what Fos actually is.