EXPRESSION OF THE HISTAMINE H1 RECEPTOR GENE IN RELATION TO ATHEROSCLEROSIS

Histamine in serum and arterial tissue contributes to the pathogenesis of atherosclerosis and the formation of coronary artery vasospasm As the effect of histamine at a given site will be mediated by its specif ic receptors, we investigated by in situ hybridization and Northern bl ot analysis the expression and localization of human histamine H1 rece ptor mRNA in the arterial wall and in cultured human aortic intimal sm ooth muscle cells (SMC) and immortalized SMC (ISS10) and endothelial c ells (SE1). In situ hybridization showed that SMC and endothelial cell s expressed H1 receptor mRNA in vivo and that the expression was incre ased in SMC in the thickened intima of atherosclerotic foci in both th e aorta and coronary artery By Northern blot analysis, we also detecte d histamine H1 receptor mRNA in cultured SMC, ISS10, and SE1 and found that platelet-derived growth factor stimulated SMC to increase their expression of the mRNA in vitro. These results suggest that up-regulat ion of histamine H1 receptor expression by platelet-derived growth fac tor plays an important role in the initiation and progression of cardi ovascular diseases.