The carotid bodies of renal hypertensive rats.

The carotid bodies of renal hypertensive rats (one kidney wrap model) were studied by light-microscopic and morphometric methods. Rats with established hypertension showed massive intraglomic vascular alterations, such as exudation of plasma, subendothelial fibrinoid deposits and fibrinoid necroses of the intima and media. Additionally a granuloma-like perivascular proliferation of fibroblasts and histiocytes was seen. The total carotid body volume was enlarged but the volume of the specific glomic tissue was reduced in comparison with normotensive controls. In rats with borderline hypertension similar pathological changes were found but in a more reduced extension. Additionally in these rats some intraglomic vessels showed an accumulation of acid mucopolysaccharides and an hyperplasia of mediocytes. Rats with such vessel alterations also exhibited a small enlargement of specific glomic tissue. In general the pathological changes of the carotid bodies in renal hypertensive rats are different in comparison with those in the glomera carotici of rats with spontaneous hypertension (SHR, GH rats). This study suggests that an elevated blood pressure does not solely cause an increment of the specific chemoreceptive tissue mass of the carotid bodies.