Effect of spinal fluid pressure on cerebrospinal fluid formation

Abstract The effect of spinal fluid pressure on cerebrospinal fluid (CSF) formation was measured in rabbits and cats. A decreased rate of CSF production with increased perfusion pressure was found, which was best illustrated by paired comparisons in individual animals during ventriculocisternal perfusion at both low (−5 to −10 cm H 2 O) and high (20–25 cm H 2 O) perfusion pressure. Each animal was perfused at either pressure for 2 hr (rabbits) or 2.5 hr (cats) for steady-state measurements. After a gradual change in hydrostatic pressure, perfusion continued for an additional 1.5 hr (rabbits) or 2 hr (cats) when steady-state measurements were repeated. The mean rate of CSF production decreased in rabbits from 0.0081 to 0.0045 ml/min after the perfusion pressure was elevated. This effect was independent of whether the animals were perfused initially under high or low pressure. In cats, after a similar increase in perfusion pressure, the mean rate of CSF formation decreased from 0.0212 to 0.0102 ml/min.