Increased complexity of vasopressin's vascular actions.

Vasopressin is becoming a widely used pressor in conditions with severe hypotension. Like several other hormones important in cardiovascular and extracellular fluid control, however, vasopressin can activate several receptors that when pharmacologically or pathologically stimulated may result in conflicting effects. In the present issue of Critical Care, Rehberg and colleagues examined the hypothesis that blockade of vasopressin V2 receptor during septic shock may be beneficial. Their tantalizing results indicate that future work must consider the precise vasopressin receptors that are stimulated and/or inhibited.