Role of histamine H2 receptors in cardiovascular function

ABSTRACT

The purpose of this study was to evaluate the role of histamine receptors [H[2]] in cardiovascular function in rats. The finding in the present study revealed that H[2] receptor blocker rantidine Hcl in a dose 20 mg/Kg reduces the heart rate both invivo and invitro, and abolishes the positive chronotropic action of beta - adrenergic stimulation, induced by isoproterenol infusion in isolated perfused hearts in Langendorff preparation. Moreover, it reduces the basal myocardial flow rate, with normal response to beta - adrenergic stimulation. On the other hand, the inotropic responses were unaffected. Therefore, the sympatho-inhibitory action of H[2]-blocker, suggesting a potential clinical use in conditions associated with enhanced sympathetic tone such as coronary vascular diseases and heart failure