| Abstrakt: |
The first part of the review presents data on localization of alpha 1-adrenoceptor (AR) in the heart, including plasma and nuclear membranes, on its relative concentrations in the myocardium, on three alpha1-AR (A-, B- and D-) subtypes, the two of which (A and B) are mainly expressed in the human and mouse myocardium and all the three subtypes are expressed in rat''s myocardium. It also reports that the activation of alpha 1-AR induces inotropic effect (positive, negative or biphasic), luzitropic effect, chronotropic effect (the latter can be also positive or negative), and arrhythmogenic effects. The review provides information on the mechanisms forming the basis of these effects, including the role of G q- and G i-proteins, individual isoforms of phospholipase C, phosphatidylinositol 3-kinase, phosphatidylinositol 4,5-biphosphate, diacylglycerol, inositol triphosphate, protein kinase C, protein kinase D, NO-synthase and ion channels. It discusses the literature data on the role of individual subtypes of alpha 1-AR in the implementation of these effects. It reports on the stability of alpha1-AR to desensitization, which is important for the realization by the receptors of their trophic function. |
