Scientists have discovered the reason behind one of the most common medical signs characterized by rise in body temperature, fever.
Fever is a response to inflammation, and is triggered by an onset of the signaling substance prostaglandin. Senior lecturer David Engblom from Linkoping University, Sweden, had had a breakthrough eleven years ago when he uncovered the mechanism behind the formation of prostaglandin E2 during fever.
These signaling molecules could not pass the blood-brain barrier, the purpose of which is to protect the brain from hazardous substances. Engblom showed that instead, they could be synthesised from two enzymes in the blood vessels on the inside of the brain, before moving to the hypothalamus, where the body's thermostat is located.
The study was based on tests with mice that lacked the enzymes COX-2 and mPGES-1 in the brain's blood vessels. When they were infected with bacterial toxins the fever did not appear, while other signs of inflammation were not affected.
David Engblom explained that this showed that those prostaglandins which cause fever were formed in the blood-brain barrier and nowhere else.
The study is due to be published in the Journal of Neuroscience.