Differences in the in vitro and in vivo 5-hydroxytryptamine extraction performance among three common microdialysis membranes.

摘要: : The present study summarizes the results of an in vitro and vivo comparison apparent 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid, 3,4-dihydroxyphenylacetic acid dialysis performance three types membrane frequently used intracerebral microdialysis experiments. fiber examined were a regenerated cellulose Cuprophan (GF), proprietary polycarbonate ether (CMA), polyacrylonitrile/sodium methallylsulfonate copolymer (HOSPAL). experiments unexpectedly revealed that HOSPAL membrane-equipped probes displayed clearly aberrant 5-HT diffusion dynamics compared with GF CMA probes, demonstrable not only vitro, but also In exhibited maximum relative recovery for already first 20-min sample, whereas increased very slow protracted manner over period little less than 2 h. further immediate washout when subsequently transferred to artificial CSF only-containing medium (no 5-HT), sim h was required yield near-total extinction dialysate standard probes. vivo, rat ventral hippocampal output responses K+ (100 mM) infusion, Ca2+ omission, systemic 8-hydroxy-2-(di-n-propylamino)tetralin injection all markedly retarded blunted instead used. However, extraction comparable using either types. findings are discussed terms interaction between cationic negative ionic charges membrane. anomalous shown be dependent on exposed surface area (and thus probe design), may influenced by changing perfusion flow rate or strength media in- outside probe. Our seriously caution against uncritically any without controlling its properties within context application intended. particular, usefulness at physiological pH limited.