The precise role of vasopressin in the pathophysiology of cardiovascular disease is controversial, but this peptide hormone is important for several reasons. Firstly, circulating concentrations of vasopressin are elevated in heart failure and some forms of hypertension. Secondly, there is evidence that vasopressin is synthesized not only in the hypophysial-pituitary axis but also in peripheral tissues including the heart where it acts as a paracrine hormone. Thirdly, vasopressin has vasoconstrictor, mitogenic, hyperplastic and renal fluid retaining properties which, by analogy with angiotensin 11, may have deleterious effects when present in chronic excess. Finally, the availability of orally active non-peptide vasopressin receptor antagonists allows vasopressin receptor antagonism to be considered as a therapeutic option in cardiovascular disease. Experimental Physiology (2000) 85S, 259s-265s.
VasopressinVasopressin is a major hormonal system in the body responsible for blood pressure homeostasis and for salt and water balance (Johnston, 1985; Phillips et al. 199%). Vasopressin belongs to a family of vasoactive and mitogenic peptides and has multiple actions including inhibition of diuresis, contraction of vascular smooth muscle, trophic actions, platelet aggregation, stimulation of Von Willebrand factor, liver glycogenolysis and central regulation of blood pressure and the baroreflex (Johnston, 1985; Phillips et al. 1 9 9 5~; Sampey et al. 1999). Vasopressin exerts its actions through binding to typical heptahelical transmembrane G-proteincoupled receptors with distinct second messenger systems; the V,, (vascular, hepatic) and V,, (anterior pituitary) receptors through phosphatidylinosilol hydrolysis to mobilize calcium, and the V, (kidney) receptor through adenylyl cyclase. In addition to its classical vasopressor action via the VIA receptor, vasopressin mediates vasodilatation through renal V,-like receptors (Naitoh et al. 1993; Burrell et al. 1994a). To date more than ten related complementary DNAs have been cloned and sequenced (Bichet, 1996) including rat and human vasopressin V,, receptors, human V,, receptor, rat and human V, receptors and sheep VIA receptors (Hutchins et al. 1995). These receptors are strikingly similar in both size and amino acid sequence.
Vasopressin and cardiovascular disease