Immunofluorescent demonstration of plasma protein entry into arterial wall by cholesterol, epinephrine, norepinephrine and angiotensin II.

Thepresence of IgG and beta-lipoprotein in thoracic and abdominal aortas of 33 rhesus monkeys under various conditions was observed by immunofluorescence and interference filter technique. In untreated and placebo control monkeys, a definite fluorescence due to IgG was seen in highly limited areas of the subendothelial space and the innermost layers and a weak but positive fluorescence due to beta-lipoprotein was sometimes show in highly limited spots of the subendothelial space, but not the medial layers. In challenged animals with cholesterol (1 g/kg p.o.) or epinephrine (1 mug/kg i.v.) or norepinephrine (10 mug/kg i.v.) or angiotensin II (1 mug/kg i.v.) or cholesterol (1 g/kg p.o.) plus epinephrine (1 mug/kg i.v.), definite fluorescence showing the entry of beta-lipoprotein and IgG from the vessel lumen into the subendothelial space and then into the medial layers of the arterial wall was clearly shown by serial sacrificing of animals after each challenge. The passage of beta-lipoprotein through the internal elastic lamina into the medial layer, was characteristically delayed as compared with that of IgG. In pretreated animals with pyridinolcarbamate (PDC) (10 mg/kg p.o.), EG467 (1 mg/kg p.o.) and Premarin (5 mg/kg i.v.), the acute entry of those plasma proteins was significantly inhibited.