Staining for microvascular alkaline phosphatase in thick celloidin sections of nervous tissue: morphometric and pathological applications.

Alkaline phosphatase enzyme is active in the endothelium of capillaries (and often arterioles) in the central and peripheral nervous systems of many animals including man. A modified metallic stain for this enzyme applied to thick (50-500 micron) sections of brain or nerve produces a striking picture of the microvascular system. Preparations may be examined by light microscopy or microfocal radiography. Thick sections (particularly at 100 micron) are suitable for vascular morphometry at the light microscopic level. Celloidin embedding of the material permits storage of the specimen and ensures that cohesive sections can be cut serially, labeled, and handled with ease. Counterstaining permits normal and pathological features of the parenchyma to be demonstrated in relation to the vessels. Techniques of preparation and morphometry are described. Examples are drawn from current studies of the hippocampal and calcarine microvasculatures and their relation to senile plaques in normal aging and senile dementia of the Alzheimer type.