Assessing Direct Vascular Actions of Estrogens.

Estrogens are known to affect vascular function. In order to decipher the underlying mechanisms, it is essential to study the direct actions of estrogenic substances on blood vessels. There are two widely used approaches to assess the effects of estrogenic substances directly on blood vessels, the isolated perfused intact mesenteric vascular bed (McGregor preparation) and the isolated perfused/pressurized vessel approach. The McGregor preparation relies on constant flow with vascular reactivity assessed as changes in perfusion pressure. The isolated perfused/pressurized vessel approach uses a single vessel mounted on glass micropipettes. The main readout in this approach is vascular diameter. This chapter describes these approaches which remain cornerstones in the investigation of direct vascular actions of estrogenic substances.