Scanning electron microscopic study on pineal vascularization of the common tree shrew (Tupaia glis)

The detailed blood supply including microvascularization of pineal gland in the common tree shrew (Tupaia glis) was investigated using a vascular corrosion cast technique in conjunction with scanning electron microscopy. Adult common tree shrews of both sexes, divided into 3 groups, were injected with red latex, blue vinyl resin, and Batson's No. 17 plastic mixture for the studies of arterial supply, venous drainage, and microvasculature of the pineal gland, respectively. It was found that the pineal gland is a highly vascularized organ. It receives two to four branches from the medial posterior choroidal arteries. Two types of capillary arrangements, fan-like and network, are observed. As in the human, usually one and occasionally two pineal veins, draining directly into the great cerebral vein of Galen, are observed. A pineal portal system is not demonstrated.