CHOLINERGIC INNERVATION OF VESSELS OF BASE OF BRAIN

Distribution and activity of acetylcholinesterase in the intramural nerve apparatus of vessels of the base of the [canine] brain were studied with the histochemical method of Koelle-Gomori. Arteries (268) were examined. The enzyme activity is detected in the effector nerve fibers in the wall of all cerebral vessels constituting the system of the circle of Willis. The periarterial nerve apparatus of cerebral arteries of the anterior and posterior regions of the circle of Willis consists of 2 cholinergic plexuses: superficial and deep plexus forming a multilayered neural cover. The terminal parts of cholinergic nerve fibers at the border with the muscular coat show a granular structure. Nerve cells rich in active ferment are found in the cholinergic plexuses. Difference in the character of cholinergic innervation of vessels of the internal carotid and the vertebrobasilar region has been shown. The vessels of the circle of Willis possess a reliable cholinergic system of nerve regulation which along with other systems, such as that of adrenergic nerve fibers, maintains the homeostasis of the cerebral blood flow.