From: Fluid and ion transfer across the blood–brain and blood–cerebrospinal fluid barriers; a comparative account of mechanisms and roles
Ion concentrations (mmol per litre of H2O)
LV
4th V
CSF
Plasma
Na+
49–53
46*
55–58
56*
152–156
148–155
K+
95–97
87–89
2.99–3
3.9–4.6
Cl−
62–64
67*
63–64
126–129
113–114
HCO3 −
(11)
22–24
21
pH
7.06
7.04
7.33
7.44