Histamine, récepteurs de l’histamine et anti-histaminiques : données récentes

Abstract

Histamine was discovered at the beginning of the 20th century. It has been recently shown that immunocompetent cells (T lymphocyte, dendritic cell) are capable of histamine synthesis and that histamine can regulate the Th1/Th2 balance. This immune regulation by histamine is related to its activity as a potent polarizing factor for dendritic cells, giving rise to DC2 dendritic cells that are involved in the differentiation of T helper cells towards Th2 phenotype. The majority of histamine is metabolized by N-methyltransferase. A common polymorphism of this enzyme that is associated with decreased enzyme activity has been associated with asthma. Histamine binds to four receptor types that are expressed on different types of cells and that mediate the numerous actions of histamine. H 1-receptors exhibit constitutive activity that is inhibited by several H 1-receptor antagonists, which therefore display a negative intrinsic activity called inverse agonist activity. In addition, the cerebral P-glycoprotein-mediated efflux of recent H 1-receptor antagonists may explain the lack of nervous system side effects of second-generation anti-histamines.