Distribution of H2S synthesis enzymes in the walls of cerebral arteries in rats.

The distribution of two enzymes involved in H(2)S synthesis, cystationine β-synthase (CBS) and cystationine γ-liase (CSE), was studied in the walls of the internal carotid artery, order I-V branches of the middle cerebral artery basin, and intracerebral vessels of adult Wistar rats. Immunohistochemical staining showed the presence of CBS in the endothelium of small pial arteries (order IV-V branches) and intracerebral arterioles and in the capillary walls, neurons, and vascular nerves. As for CSE, in the internal carotid artery and large (order I-II) pial branches it was found mainly in the tunica media myocytes, in order III-IV vessels in myocytes and endothelium, and in smaller pial and intracerebral vessels in the endothelium. Along with enzyme-positive vessels, many pial and intracerebral arteries contained no these enzymes in the walls.