Cerebrospinal fluid cyclic AMP and acid monoamine metabolites following probenecid: studies in psychiatric patients

At probenecid levels greater than 10 microgram/ml, CSF cAMP was independent of CSF probenecid concentration. At these levels of probenecid, cAMP transport out of CSF is probably maximally blocked and cAMP levels reflect cAMP release into CSF. CSF cAMP was significantly higher in RDC-diagnosed schizophrenics than in other psychotics or depressives. A significant decrease in CSF cAMP was found in psychotic patients treated with chlorpromazine, No changes in CSF cAMP were observed in patients treated with tricyclic antidepressants or lithium.