The effect of anaesthetic agents on the cerebrospinal fluid clearance of ³⁵S-sulphate and ¹²⁵I-iodide

In recent years, use of the ventriculocisternal perfusion technique for the study of cerebrospinal fluid transport of substances has become prevalent. This report compares the effect of three anesthetic agents, commonly used in the laboratory, on the clearance of ³⁵S-sulfate and ¹²⁵I-iodide out of the CSF. When compared with chloralose, pentobarbital and (to a lesser extent) urethane inhibit the CSF clearance of these anions. In studies with isolated choroid plexus incubated in vitro, the accumulation of ¹²⁵I-iodide was found to be significantly less in the choroid plexus obtained from the anesthetized than from the unanesthetized animal. These results suggest that the reduced CSF clearance observed in vivo was a result, at least in part, of inhibition of choroid plexus transport.