ARTERIAL PULSATION-DEPENDENT PERIVASCULAR CEREBROSPINAL-FLUID FLOW INTO THE CENTRAL CANAL IN THE SHEEP SPINAL-CORD

The impetus for the enlargement of syringes is unknown. The authors hy pothesize that there is a flow of cerebrospinal fluid (CSF) from periv ascular spaces into the central canal and that the flow is driven by a rterial pulsations. Using horseradish peroxidase as a tracer, the CF f low was studied in normal sheep, in sheep with damped arterial pulsati ons, and in sheep with lowered spinal subarachnoid pressure. The CSF f low from perivascular spaces into the central canal was demonstrated i n the normal sheep, and two patterns of flow were identified: 1) from perivascular spaces in the central gray matter; and 2) from perivascul ar spaces in the ventral white commissure. Flow into the central canal was also observed in the sheep with lowered spinal subarachnoid press ure, but not in those with reduced arterial pulse pressure. This study provides evidence that CSF flow from perivascular spaces into the cen tral canal is dependent on arterial pulsations. Arterial pulsation-dri ven CSF flow may be the impetus for the expansion of syringes.