Screening of multidrug-resistance sensitive drugs by in situ brain perfusion in P-glycoprotein-deficient mice.
OBJECTIVE
This study was conducted to assess the influence of P-glycoprotein (P-gp) on brain uptake of multidrug resistance sensitive drugs using an in situ brain perfusion technique in P-gp-deficient (mdr1a[-/-]) and wild-type mice.


METHODS
The blood-brain transport of radiolabeled vinblastine, vincristine, doxorubicin, colchicine, and morphine was evaluated in mdr1a(-/-) and wild-type CF-1 mice with the in situ brain perfusion technique. Brain uptake of drugs after intravenous pretreatment with P-gp reversal agents, (PSC 833, GF 120918, or (+/-)-verapamil), or vehicle also was studied in wild-type mice. In all experiments, cerebral vascular volume was determined by co-perfusion of sucrose.


RESULTS
Cerebral vascular volume was preserved during perfusion, indicating maintenance of blood-brain barrier integrity in both types of mice within the concentration range of substrates in the perfusate. The apparent brain transport of colchicine. vinblastine, doxorubicin, and morphine was increased 3.0, 2.7, 1.5, and 1.4-fold, respectively, in mdr1a(-/-) mice compared with the wild-type: the brain uptake of vincristine was not affected by P-gp. Preadministration of PSC 833 or GF 120918 in wild-type mice led to a -3-fold increase in the brain transport of colchicine and vinblastine, but no effect was observed for the other compounds. Intravenous verapamil enhanced colchicine brain transport (1.8-fold), but failed to increase the brain uptake of vinblastine and morphine.


CONCLUSIONS
The in situ brain perfusion technique appears to be a sensitive and powerful tool for medium throughput screening of the brain uptake of multidrug resistance sensitive drugs. The effect of P-gp is characterized more efficiently with mdr1a(-/-) mice than by using modulators of P-gp in wild-type mice.
Cisternino
S
S
Inserm U26, Hĵpital F. Widal, Paris, France. salvatore.cisternino@inserm.lrb.ap-hop-paris.fr
Rousselle
C
C
Dagenais
C
C
Scherrmann
J M
JM
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000172:deficiency / Q000187:drug effects / Q000378:metabolism*; D000166:Acridines / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000493:pharmacokinetics; D001692:Biological Transport; D001812:Blood-Brain Barrier; D001921:Brain / Q000378:metabolism*; D003078:Colchicine / Q000493:pharmacokinetics; D003524:Cyclosporins / Q000494:pharmacology; D004317:Doxorubicin / Q000493:pharmacokinetics; D018432:Drug Resistance, Multiple / Q000502:physiology*; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D051379:Mice; D010477:Perfusion; D044005:Tetrahydroisoquinolines; D013997:Time Factors; D014700:Verapamil / Q000494:pharmacology; D014747:Vinblastine / Q000493:pharmacokinetics
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000166:Acridines; D000970:Antineoplastic Agents; D003524:Cyclosporins; D007546:Isoquinolines; D044005:Tetrahydroisoquinolines; D014747:Vinblastine; D004317:Doxorubicin; D014700:Verapamil; C083501:Elacridar; C070272:valspodar; D003078:Colchicine