1985 Volume 48 Issue 2 Pages 173-181
Arachnid granulations are not always present in lower mammals and primate newborns. In order to visualize the route for the cerebrospinal fluid (CSF) to drain into the venous system, horseradish peroxidase (HRP) was injected into the lateral ventricle or cisterna cerebellomedullaris of the mouse and rat.
From 30 to 60min after the commencing of a slow infusion for 15-30min of 0.05-0.1ml solution containing 10-20mg HRP, the mouse, whose skull had been exposed, was dropped into cold acetone at dry ice temperature; other animals were fixed by perfusion with aldehyde solution. The frozen head was dissected in a cryostat kept at -18°C to remove the skull, but leave the dura mater and the falx cerebri. The brain with meninges was cut into 30-45μm sagittal sections in the cryostat, and processed for peroxidase reaction. The perfusion-fixed brains were used for scanning electron microscopy and for electron microscope observation of the tracer.
The reaction product was found within fenestrated venous capillaries of the choroid plexus. The route for the HRP in the CSF to drain into the sinus rectus via the vena chorioidea and vena cerebri magna was directly visualized in the mouse.