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Carrier-mediated Cocaine Transport at the Blood-Brain Barrier as a Putative Mechanism in Addiction Liability

Hélène Chapy, Maria Smirnova, Pascal André, Joël Schlatter, Fouad Chiadmi, Pierre-Olivier Couraud, Jean-Michel Scherrmann, Xavier Declèves, Salvatore Cisternino

Int J Neuropsychopharmacol. 2014 Oct 31;18(1):pyu001.

PMID: 25539501

Abstract:

Background:
The rate of entry of cocaine into the brain is a critical factor that influences neuronal plasticity and the development of cocaine addiction. Until now, passive diffusion has been considered the unique mechanism known by which cocaine crosses the blood-brain barrier.
Methods:
We reassessed mechanisms of transport of cocaine at the blood-brain barrier using a human cerebral capillary endothelial cell line (hCMEC/D3) and in situ mouse carotid perfusion.
Results:
Both in vivo and in vitro cocaine transport studies demonstrated the coexistence of a carrier-mediated process with passive diffusion. At pharmacological exposure level, passive diffusion of cocaine accounted for only 22.5% of the total cocaine influx in mice and 5.9% in hCMEC/D3 cells, whereas the carrier-mediated influx rate was 3.4 times greater than its passive diffusion rate in vivo. The functional identification of this carrier-mediated transport demonstrated the involvement of a proton antiporter that shared the properties of the previously characterized clonidine and nicotine transporter. The functionnal characterization suggests that the solute carrier (SLC) transporters Oct (Slc22a1-3), Mate (Slc47a1) and Octn (Slc22a4-5) are not involved in the cocaine transport in vivo and in vitro. Diphenhydramine, heroin, tramadol, cocaethylene, and norcocaine all strongly inhibited cocaine transport, unlike benzoylecgonine. Trans-stimulation studies indicated that diphenhydramine, nicotine, 3,4-methylenedioxyamphetamine (ecstasy) and the cathinone compound 3,4-methylenedioxypyrovalerone (MDPV) were also substrates of the cocaine transporter.
Conclusions:
Cocaine transport at the BBB involves a proton-antiporter flux that is quantitatively much more important than its passive diffusion. The molecular identification and characterization of this transporter will provide new tools to understand its role in addictive mechanisms.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP61585226 Norcocaine hydrochloride solution Norcocaine hydrochloride solution 61585-22-6 Price
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