Effect of intracranial pressure on cerebrospinal fluid formation in isolated brain ventricles

The formation of cerebrospinal fluid: Nearly a hundred years of interpretations and misinterpretations

“…In spite of the existence of the choroid plexuses in isolated brain ventricles there is no tendency for the dilatation of the brain ventricles in physiological conditions (Kappers, 1958;Oppelt et al, 1964). If we add to this the results demonstrating that CSF formation within isolated brain ventricles in cats is, at physiological pressure, in balance with CSF absorption (Orešković et al, 1991;) and that, under physiological conditions in free moving cats, CSF absorption within the ventricles takes place, to a significant extent, also in an open ventricular system (Bulat et al, 2008), it may be expected that a significant and constant exchange occurs between CSF and the surrounding ventricular tissue.…”

“…It should also be pointed out that experimental results, which suggest a significant portion of CSF formation outside the brain ventricles were obtained (Di Chiro, 1964;Orešković et al, 1991;Sato et al, 1972;Sato et al, 1971;Sato and Bering, 1967). On the basis of these studies, it may be concluded that CSF is formed within the entire fluid system and that it is not mainly related to the brain ventricles and consequently to the choroid plexuses.…”

“…In other words, there is no net CSF formation under normal conditions, especially not only inside the brain ventricles, and it seems that CSF appeared and disappeared everywhere in the CSF system. Experimental results (Di Chiro, 1964;Orešković et al, 1991;Sato et al, 1972;Sato et al, 1971;Sato and Bering, 1967) also show that CSF is formed outside the brain ventricles (in subarachnoid space). The results also show that CSF absorption occurs not only through villi arachnoidales, but also inside the brain ventricles (Brightman, 1968;Bulat et al, 2008;Cserr, 1971;Dodge and Fishman, 1970;Foley, 1921;Hassin, 1924;Orešković et al, 1991;Wright, 1972), along the nerve roots (Kido et al, 1976), from the subarachnoid space into the lymphatic system (Bradbury, 1981;Brierly and Field, 1948;Dandy, 1929;Johnston et al, 2005;Johnston et al, 2004;Koh et al, 2005;Koh et al, 2006;Weed, 1914), and high intraspinal absorption (Edsbagge et al, 2004).…”

“…These results, obtained from different experiments on animals, cannot be explained by the classic hypothesis of CSF formation since Vf is considered to be active and energy consuming, and should bear on ICP, especially because a force under + 30 cm H 2 O is not sufficient to affect an active process (Pollay et al, 1983). In other words, it seems that CSF formation may occur as a result of a passive process rather than an active one, and that the volume of CSF is regulated by hydrostatic pressure (Bulat, 1993;Orešković et al, 2000;Orešković et al, 1991).…”

“…The control of CSF volume is under the influence of hydrostatic and osmotic forces (Bulat, 1993;Orešković et al, 2000;Orešković et al, 2002;Orešković et al, 1991) between the CSF system and the surrounding tissue ( Figure 8D), and CSF volume will change depending on the prevalence of those forces, caused by (patho)physiological reasons inside or outside of the CSF system, in fact, in a manner similar to the way they regulate the volume of extracellular fluid in other organs (Figure 8). …”