Donepezil, a cholinesterase inhibitor used in Alzheimer's disease therapy, is actively exported out of the brain by abcb1ab p-glycoproteins in mice.

Polymorphisms in the drug transporter gene ABCB1 predict the treatment response of selected antidepressants and limit anticonvulsive medication's effectiveness. The ABCB1 locus encodes the energy-dependent transporter P-glycoprotein (P-gp) of the blood brain barrier (BBB), which serves as an efflux pump of its substrates in the expressing tissues of vertebrates. One experimental setup to determine a posteriori the P-gp substrate status is the use of the double abcb1ab knock-out (KO) mice model. Since so far, P-gp substrate status of donepezil, a cholinesterase inhibitor wildly used in Alzheimer's disease therapy was inconclusive, we performed subcutanous (s.c.), continuous injections over 11 days in double abcb1ab KO and P-gp competent wildtype (WT) mice. Both in brain and in testis concentrations of donepezil were significantly higher in P-gp deficient mice compared to WT controls (2.39 and 2.24 times respectively). In conclusion, in mice donepezil's brain bioavailability depends on P-gp.

abcb1ab p-glycoprotein is involved in the uptake of the novel antidepressant vortioxetine into the brain of mice.

A clinically important and well-studied transporter of the blood-brain barrier (BBB) is P-glycoprotein (P-gp), the gene product of ABCB1. Animal studies have shown that brain concentrations of many antidepressants depend on P-gp. However, biochemical properties, which might allow the prediction of pharmacodynamical involvement of P-gp have not yet been identified, hence thorough experimental testing of each novel drug is needed to determine its P-gp substrate status. In the current study, we tested the P-gp substrate status for the antidepressant vortioxetine using double abcb1ab knock-out (KO) mice. Cerebral concentrations of vortioxetine were 2.3 times higher in P-gp deficient mice compared to wildtype (WT) controls. No significant difference was found regarding the concentration of the drug in the plasma and other organs (liver, kidney, spleen) between KO and WT mice. The results of our study provide conclusive in-vivo evidence that in mice vortioxetine's brain bioavailability is P-gp dependent, expanding previous findings on this topic.