Cholinergic nerve fibres associated with the microvessels of the human cerebral cortex: a study based on monoclonal immunocytochemistry for choline acetyltrasferase

The distribution of cholinergic nerve fibres associated with the microvascu lature of the human parietal cerebral cortex was investigated by immunocyto chemistry, employing monoclonal antibodies against choline acetyl-transfera se, the acetylcholine-synthesizing enzyme. The results revealed strongly im munoreactive nerve fibres in the tunica adventitia of arterioles penetratin g the superficial cortical layers from the pial vasculature. Networks of st ained nerve fibres were seen within the tunica muscularis of the radially d irected arterioles that cross the intermediate and deep cortical laminae, a nd of their transverse and recurrent branches. Tiny positive nerve fibres w ere also seen around the cortex capillaries, some reaching the endothelial cells. The morphological data support the involvement of acetylcholine in m icrovasculature local regulation, possibly with a differentiated role in th e arterioles and capillaries.