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PubMed1982

Binding properties of circulating Evans blue in rabbits as determined by disc electrophoresis.

Following injections of Evans blue (1-200 mg/kg) into rabbits, polyacrylamide gel disc electrophoresis showed that Evans blue binds to two protein fractions. The greater part was bound to albumin and the remainder to a plasma protein in the postalbumin fraction. Unbound Evans blue was present in each plasma sample analyzed. Attempts to liberate the dye from the coloured areas of the aorta and common carotid arteries by tissue electrophoresis failed unless very high concentrations of Evans blue were used. This indicates that at the concentrations used by many investigators areas dyed by Evans blue may not be equated with the presence of diffusible protein-dye complexes.

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PubMedDate not supplied

Increased contractile responses of isolated arteriosclerotic rabbit carotid arteries to various vasoactive stimuli.

Clinical observations indicate that atherosclerotic vessels are prone to develop vasospasm. It was assumed that this property is related to hypercholesterolemia, but the basic mechanisms are still unknown. To investigate further mechanical stimulation experiments were performed with segments of rabbit carotid arteries. Arteriosclerotic lesions were induced in vivo in these arteries by application of DC impulses either in hyper- or normo- cholesterolemic animals. Contractions were evoked by noradrenaline, KCl or hydrogen peroxide. The results show that all the arteriosclerotic segments were hypersensitive to noradrenaline and hydrogen peroxide, compared with the corresponding controls. An increase in contraction force was also found upon application of KCl to lipid-containing plaques. However, in arteriosclerotic segments obtained from normally fed animals, the contraction response to KCl was lower than in controls. This indicates that complex alterations in the contractile properties occur in smooth muscle during atherogenesis which cannot be explained solely on the basis of the influence of cholesterol on the arterial cells.

Animals↗