Fig. 3.

CSF secretion against an osmotic gradient. CSF secretion measured with different transchoroidal osmotic gradients demonstrate the ability of the choroid plexus to secrete CSF in the absence of an osmotic gradient (dotted vertical line) and even when faced with an osmotic gradient in the opposite direction to that of the CSF secretion (left side of the panel). The graph is adapted from [69] and based on published experimental findings in rabbit, cat, goat, and rat [30, 58, 90–93, 208, 209]