Purpose
The lithium disposition to cerebrospinal fluid (CSF) was evaluated in rats with acute renal failure (ARF) to examine whether
electrolyte homeostasis of the CSF is perturbed by kidney dysfunction. In addition, the effects of renal failure on choroid
plexial expressions of the Na+–K+–2Cl− co-transporter (NKCC1) and Na+/H+ exchanger (NHE1) were also studied.
Methods
After lithium was intravenously administered at a dose of 4 mmol/kg, its concentration profile in plasma was evaluated by
collecting plasma specimens, while that in CSF was monitored with a microdialysis probe in the lateral ventricles. NKCC1 and
NHE1 expressions were measured via the Western immunoblot method using membrane specimens prepared from the choroid plexus
in normal and ARF rats.
Results
The lithium concentration in CSF of ARF rats was 30% lower than that of normal rats, while their plasma lithium profiles were
almost the same, indicating that the lithium disposition to CSF was decreased in ARF rats. It was revealed that the choroid
plexial expression of NKCC1 was increased by 40% in ARF rats, but that of NHE1 was unchanged.
Conclusion
ARF decreases the lithium disposition to CSF, possibly by promoting lithium efflux from CSF due to increased NKCC1 expression
in the choroid plexus.
KEY WORDS acute renal failure - cerebrospinal fluid (CSF) - choroid plexus - lithium - Na+–K+–2Cl− co-transporter (NKCC1)