Donepezil, tacrine and alpha-phenyl-n-tert-butyl nitrone (PBN) inhibit choline transport by conditionally immortalized rat brain capillary endothelial cell lines (TR-BBB).
In the present study, we have characterized the choline transport system and examined the influence of various amine drugs on the choline transporter using a conditionally immortalized rat brain capillary endothelial cell line (TR-BBB) in vitro. The cell-to-medium (C/M) ratio of [3H]choline in TR-BBB cells increased time-dependently. The initial uptake rate of [3H]choline was concentration-dependent with a Michaelis-Menten value, Km, of 26.2 +/- 2.7 microM. The [3H]choline uptake into TR-BBB was Na+-independent, but was membrane potential-dependent. The [3H]choline uptake was susceptible to inhibition by hemicholinium-3, and tetraethylammonium (TEA), which are organic cation transporter substrates. Also, the uptake of [3H]choline was competitively inhibited with Ki values of 274 microM, 251 microM and 180 microM in the presence of donepezil hydrochloride, tacrine and alpha-phenyl-n-tert-butyl nitrone (PBN), respectively. These characteristics of choline transport are consistent with those of the organic cation transporter (OCT). OCT2 mRNA was expressed in TR-BBB cells, while the expression of OCT3 or choline transporter (CHT) was not detected. Accordingly, these results suggest that OCT2 is a candidate for choline transport at the BBB and may influence the BBB permeability of amine drugs.
Kang
Young-Sook
YS
College of Pharmacy, Sookmyung Women's University, Seoul, Korea. yskang@sookmyung.ac.kr
Lee
Kyeong-Eun
KE
Lee
Na-Young
NY
Terasaki
Tetsuya
T
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000378:metabolism*; D001921:Brain / Q000098:blood supply* / Q000166:cytology / Q000378:metabolism; D002461:Cell Line, Transformed; D002491:Central Nervous System Agents / Q000494:pharmacology*; D002794:Choline / Q000378:metabolism*; D003497:Cyclic N-Oxides; D000077265:Donepezil; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D007189:Indans / Q000494:pharmacology; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D009589:Nitrogen Oxides / Q000494:pharmacology; D027701:Organic Cation Transport Proteins / Q000096:biosynthesis; D010880:Piperidines / Q000494:pharmacology; D050480:Plasma Membrane Neurotransmitter Transport Proteins; D051381:Rats; D027981:Symporters / Q000096:biosynthesis; D013619:Tacrine / Q000494:pharmacology
D002491:Central Nervous System Agents; D003497:Cyclic N-Oxides; D007189:Indans; D009419:Nerve Tissue Proteins; D009589:Nitrogen Oxides; D027701:Organic Cation Transport Proteins; D010880:Piperidines; D050480:Plasma Membrane Neurotransmitter Transport Proteins; D027981:Symporters; C075746:Slc6a8 protein, rat; C029217:phenyl-N-tert-butylnitrone; D013619:Tacrine; D000077265:Donepezil; D002794:Choline