Passage of Amipaque (metrizamide) through the arachnoid granulations

Abstract

125I labelled Amipaque (metrizamide) was introduced by cisternal puncture into six rabbits and perfused at various pressures. The torcular was exposed, frozen rapidly, and excised intact. Sections of arachnoid proliferations were made from the frozen specimen and either freeze dried or sandwiched directly for autoradiography. Some specimens were freeze dried en bloc prior to sectioning and sandwiching. All sections were exposed for 2-3 weeks at -80 degrees C prior to development of the autoradiographs. On microscopic examinations of the autoradiographs most of the activity was in the tubules or between cells suggesting intercellular passage. Some label was also present within the brain. The significance of this is discussed.

Scanning electron microscope study of human arachnoid villi

“…In contrast, some ultrastructural studies and most physiological investigations seem to demonstrate that gaps between endothelial cells lining the villi and tubule-like endothelium-lined structures may provide open communications between the subarachnoid spaces and the venous system. 8-~ 1, [13][14][15][16]18,[20][21][22][23][24][25][26][27]37,38 It must be emphasized that all the above studies were carried out on various species of laboratory animals.…”