Table I.
Expression and Localization of Drug Transporters (Human and Other Species) at the Blood-Brain Barrier
| Transporter | Localization | Expression | Activity | |
|---|---|---|---|---|
| Uptake transporters | LAT1 | L, A | Brain capillaries (h, r, m) | Characterized in rat brain capillary cellsand is situ perfusion |
| LAT2 | mRNA-h, r, m | None or minimal | ||
| MCT1 | L, A (only for rats) | Brain capillaries (h, r, m, mo, ma) and CMEC/D3 | Characterized in RBE4 cells, in situ perfusion and in vivo brain microdialysis in rats | |
| MCT8 | Brain capillaries (h, mo) | |||
| Cnt1 | Rodent brain | |||
| Cnt2 | Rodent brain | Rat brain endothelial cells | ||
| ENT1 | L (only for rats) | Brain capillaries (h, r, m) | ||
| ENT2 | Brain capillaries (h, r, m) | |||
| OAT3 | mRNA-hCMEC/D3 and BB19 | |||
| Oat2 | r | |||
| Oat3 | L, A | r, m | Rat brain | |
| OAT4 | mRNA-BB19 | |||
| OATP1A2 | brain capillaries and microvessels (h) | |||
| OATP1C1 | Brain capillaries (h) | |||
| OATP2B1 | Brain capillaries (h) | |||
| Oatp1c1 | L, A | Brain capillaries (m, r) | ||
| Oatp2b1 | Brain capillaries (m, r) | |||
| Oatp1a4 | L, A | Characterized | ||
| OCT1 | L (r, h) | Human and rat brain endothelial cells | ||
| OCT2 | L (r, h) | Human and rat brain endothelial cells | ||
| OCT3 | Protein-h | |||
| mRNA-m | ||||
| Efflux transporters | Pgp | L (h, r, m), A (h) | Brain capillaries (h, r, m) | Immortalized brain capillary cell lines, hCMEC/D3 and RBE4 |
| BCRP | L (h, m, r) | Brain capillaries, hCMEC/D3, BB19 | ||
| MRP1 | L, A (r) | Protein-hCMEC/D3 | ||
| mRNA-h, BB19 | ||||
| MRP2 | L (m, r) | mRNA-h, BB19 | Mouse | |
| MRP3 | mRNA-h | |||
| MRP4 | L, A | Protein-brain capillaries (h, m, r, mo, ma), hCEMC/D3, BB19 mRNA-m | Brain capillary endothelial cells | |
| MRP5 | L | mRNA-h, BB19 | ||
| MRP6 | mRNA-h | |||
| OCTN2 | mRNA-h, m, r | Human, rat, and mice primary brain capillary endothelial cell |
L luminal side, A abluminal side, h human, r rats, m mice, mo monkey, ma marmoset