Cocaine Hydrolase Encoded in Viral Vector Blocks the Reinstatement of Cocaine Seeking in Rats for 6 Months

A potential approach to treating cocaine addiction (or overdose) involves a naturally occurring enzyme called butyrylcholinesterase (BChE), which has the ability to metabolize, or convert, cocaine into other compounds via a chemical process called hydrolysis. The BChE normally produced in the body cannot metabolize cocaine efficiently enough to prevent the drug from reaching its targets in the brain, where it produces its rewarding effects. But researchers have created compounds based on BChE with greatly enhanced cocaine-metabolizing properties, and in a previous study such an enzyme, a cocaine hydrolase, was used to temporarily block cocaine-seeking in an animal model of relapse.  In this new study, the researchers extended the effectiveness of this treatment by giving cocaine-dependent animals a single injection of a virus modified with DNA for producing the cocaine-metabolizing enzyme. Over a period of six months, those rats did not engage in cocaine-seeking behavior even when primed with cocaine injections (in contrast to the control group), and they still had high levels of the enzyme in their bodies at the end of the study. The authors suggest that using a viral delivery system for such a cocaine-metabolizing enzyme shows promise as a way to promote resistance to relapse in cocaine addiction, particularly if the treatment is combined with cocaine vaccines currently being studied.

Diagram showing a mouse chemical symbols for cocaine and benzoylecgonine

Biol Psychiatry. Epub 2011 Dec. - http://www.ncbi.nlm.nih.gov/pubmed/22209637