[Spread of the dilatational reactions in the pial artery system to the microapplication of strychnine to the surface of the brain].

In anesthetized adult rabbits, organization of pial arterial bed and responses of its elements to microapplication of strychnine, were studied. The pial arterial responses were primarily related to the vessels' structural and functional features. The most considerable dilatation was characteristic of the precortical arteries. The reactions of sphincters of offshoots and smaller pial arteries were almost similar. The least dilatation occurred in larger pial arteries (over 100 mu in diameter). The limits of the vasodilatation were the microanastomoses which separated individual "terminal microvascular units" in the pial arterial bed. The data obtained show that the anatomy of the pial arterial bed provides a possibility for relatively independent regulation of microcirculation in rather small areas of cerebral neocortex.