Effect of E6, a novel calmodulin inhibitor, on activity of P-glycoprotein in purified primary cultured rat brain microvessel endothelial cells.
OBJECTIVE
To study the effect of E6, a novel calmodulin inhibitor, on the activity of P-glycorprotein (P-gp) in purified primary cultured rat brain microvessel endothelial cells (RBMEC).


METHODS
Flow cytometry was used to purify RBMEC from other cell types. Fluorescence of P-gp substrate rhodamine123 (Rh123) in RBMEC was measured to evaluate the effect of E6 on the function of P-gp.


RESULTS
Purified RBMEC was obtained after being sorted from other cell types by flow cytometry. Intracellular fluorescence of Rh123 in RBMEC increased after incubation with E6 3, 10 micromol/L or verapamil (VER) 50 micromol/L (P<0.01), respectively. After the treatment of E6 10 micromol/L, intracellular Rh123 accumulation was increased nearly to 3-fold. E6 and VER have no effect on accumulation of Rh123 in human umbilical vein endothelial cells (HUVEC), which do not express P-gp.


CONCLUSIONS
E6 exhibited a strong inhibitory effect on the activity of P-gp in RBMEC.
Zhu
Hao-Jie
HJ
Department of Pharmacology, China Pharmaceutical University, Nanjing 210009, China.
Liu
Guo-Qing
GQ
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000470:Alkaloids; D000818:Animals; D044182:Benzylisoquinolines / Q000138:chemical synthesis / Q000494:pharmacology*; D001812:Blood-Brain Barrier / Q000187:drug effects; D001921:Brain / Q000098:blood supply; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D002196:Capillaries; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D051381:Rats; D020112:Rhodamine 123 / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology / Q000378:metabolism
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000470:Alkaloids; D044182:Benzylisoquinolines; D002147:Calmodulin; C488276:E6 isoquinoline; D020112:Rhodamine 123; C027870:berbamine