Specimens of cerebral cortex from normal and hydrocephalic mice of the hy 3/hy 3 strain were fixed by freeze substitution and prepared for examination in an electron microscope. From randomly selected electron micrographs, the volume of extracellular space at various stages of postnatal development was estimated stereometrically. During the initial stage of hydrocephalus (postnatal day 10), when the aqueduct of Sylvius is patent and the lateral ventricles are enlarging, the volume of cortical extracellular space was about half that of normal litter mates. At day 16, following compression of the aqueduct, this extracellular space enlarged by 200-300% (about twice that of normal litter mates). One possible cause for this could be the establishment of a novel pathway for circulation of cerebral spinal fluid. The patency of this alternate pathway was confirmed by the rapid distribution of intraventricular lanthanum in cortical extracellular space. During the final stage of hydrocephalus (after 21 days) a communication between the ventricular system and subarachnoid space was established through the occipital cortex. At this time, the volume of extracellular space returned to normal levels. It is not possible at this time to ascertain whether the occlusion of the aqueduct is the cause or the result of the enlarged extracellular space. The establishment of a compensatory alternate pathway for circulation of cerebral spinal fluid in the hydrocephalic brain reveals the dynamic nature of the brain extracellular space.
|Original language||English (US)|
|Number of pages||10|
|State||Published - 1973|
ASJC Scopus subject areas
- Clinical Neurology