Histamine increases blood flow and vascular permeability. This would account for all of the following changes that occur during
inflammation, exceptswelling of the inflamed tissue.redness of the inflamed tissue.movement of defense proteins and cells into the interstitial space.chemotaxis of phagocytes.heat of the inflamed tissue.
Histamine is a chemical involved in inflammation but it also has role as a neurotransmmiter in central nervous system and uterus It is synthesized by the two types of cells: basophils and mast cells and it acts via binding to its receptors (histamine receptors). Roles of histamine are:
vasodilatation and consequently decrease in the blood pressure
increase vascular permability in the nose cavity (runny nose)
regulates sleep-wake cycle
stimulates gastric acid secretion in the stomach etc.