Visceral oedema and increased vascular permeability in early experimental hypertension

Increased vascular permeability and visceral oedema without significant hypertension or arterial damage was found in clip-nephrectomized rats dying in the first post-operative week. Increased vascular permeability was demonstrated by intravenous colloidal carbon labelling, and was restricted to capillaries and venules. Rats surviving the first week became hypertensive, and visceral oedema with predominantly venular and capillary labelling continued, although carbon was now present in arteries also, associated with smooth muscle necrosis. These results suggest that the pressor and permeability effects of renal artery constriction are independent.