IN-VITRO EFFECTS OF FENTANYL, METHOHEXITAL, AND THIOPENTAL ON BRAIN ENDOTHELIAL PERMEABILITY

Background The use of anesthetics can lead to changes of the permeabil ity of the blood-brain barrier (BBB). To eliminate those factors, such as varying hemodynamic effects that are associated with anesthesia, a n in vitro model of the BBB consisting of brain microvascular endothel ial cells (BMEC) was used to study the direct effects of the opiate, f entanyl, and the barbiturates methohexital and thiopental, which are w idely used in the clinical setting, on the permeability of confluent m onolayers. Methods: BMEC isolated from porcine brains were grown to co nfluence on collagen-coated polycarbonate membranes, which were placed into 24 well dishes, thus farming a two-compartment chamber. The perm eability of the BMEC monolayer to ions-determined by measurements of t he transendothelial resistance (TER)-the passage of sucrose, Evans Blu e albumin (EBA), and alpha-aminoisobutyric acid (AIB) across the BMEC monolayer were assessed in the presence and absence of fentanyl (25-10 0 ng/ml), methohexital (10-50 mu g/ml), and thiopental (25-100 mu g/ml ). Results: The permeability of cultured BMEC to the tracers used incr eased significantly after exposure of the monolayer to arabinose and a fter removal of calcium ions. Fentanyl, methohexital, and thiopental d id not change the permeability of the cell monolayer to ions, sucrose, albumin, and AIB. Only thiopental at the concentration of 100 mu g/ml increased the flux of AIB. Conclusions: At the concentrations tested, there is little evidence of changes in the permeability of the in vit ro BBB caused by fentanyl, methohexital, and thiopental regarding the para-and transcellular route of ions, sucrose, and albumin. Only thiop ental at a concentration of 100 mu g/ml increased the passage of AIB a cross the BMEC monolayer.