Role of Endogenous Serotonin in the Regulation of Blood Pressure in Patients with Chronic Renal Failure

Although the pathogenesis of hypertension in patients on maintenance haemodialysis is not completely understood, one of the important contributing factors is an increase in total peripheral vascular resistance (Kim et al. 1972). Page and McCubbin (1953) discovered the monoamine serotonin and suggested it may have a role in the regulation of blood pressure. However, its function in the regulation of blood pressure is still unclear. Clinical investigations of the serotonin S2-receptor antagonist ketanserin have shown that ketanserin reduces systemic vascular resistance and lowers blood pressure following acute or long term administration in patients with essential hypertension (De Cree et al. 1981; Fagard et al. 1984; Wenting et al. 1984). In this study, the acute effects of ketanserin on blood pressure and hormonal responses in 10 patients on maintenance haemodialysis with hypertension were determined in order to assess the role of endogenous serotonin in the regulation of blood pressure in such patients. The long term effect of ketanserin on pressor responsiveness to the £x,-adrenoreceptor agonist phenylephrine was also determined in 5 patients. 1. Methods