[Changes in microcirculation by the administration of sodium nitroprusside and nitroglycerin]

The effects of hypotension induced by sodium nitroprusside (SNP) or nitroglycerin (NTG) were evaluated in hamsters (n = 12). No differences in macrohemodynamic parameters were found during and after hypotension with either drug tested. SNP dilated predominantly the precapillaries and NTG dilated all microvascular segments. Blood cell velocity decreased in both groups. A significant volume of blood was diverted through av-shunts during SNP hypotension of 40 mm Hg. Capillary density decreased significantly during and after SNP-induced hypotension, whereas capillary density remained unchanged when NTG was used. The data favour the use of NTG when hypotension is deliberately induced.