Effects of Chronic Tobacco Smoking on the Distribution of Tachykinin Receptors in Rat Pial Arteries

Resumo

Pial arteries of different diameter were studied in intact rats and after 6-month modeling of chronic tobacco smoking in rats. Expression of tachykinin NK1 receptors in pial arteries was studied by biomicroscopy and immunohistochemical methods. Chronic tobacco smoking induced considerable reorganizations of the arterial bed. The intensity of changes depended on the diameter of vessels. In small pial vessels that directly participate in the blood supply to the brain, pronounced vasodilatation and enhanced expression of NK₁ receptors in the endothelium mediating the effects of substance P were observed; the number of these vessels also increased. The intensity of the response to tobacco smoke components decreased with increasing vessel diameter.