The effect of cerebrospinal fluid pressure on the size of drainage pathways

The cerebrospinal fluid drainage pathways were studied using labeled molecules of different sizes. Following determination of the limiting size, the cerebrospinal fluid pressure was raised above the normal range and changes in transfer were measured. These data show that molecules smaller than the limiting size will transfer at an increased rate in response to elevated pressures. Larger molecules did not demonstrate an increased transfer with raised cerebrospinal fluid pressures, suggesting that the pathways did not enlarge.