THURSDAY, July 28 (HealthDay News) -- Researchers say they're seeing promising results in animals from a vaccine designed to prevent a heroin high.

The vaccine produces antibodies -- a part of the immune system -- that appear to prevent heroin from reaching the brain and producing euphoria, the study authors explained.

"In my 25 years of making drug-of-abuse vaccines, I haven't seen such a strong immune response as I have with what we term a dynamic anti-heroin vaccine," principal investigator Kim D. Janda, a chair in chemistry at The Scripps Research Institute, said in an institute news release. "It is just extremely effective. The hope is that such a protective vaccine will be an effective therapeutic option for those trying to break their addiction to heroin."

Janda and his colleagues have already produced vaccines that try to stop the effects of cocaine and nicotine; they're being tested in humans. The new heroin vaccine targets both heroin and a chemical produced by its breakdown.

Addicted rats that were given the vaccine were also less likely to self-administer more heroin, in contrast to the ones that did not get the vaccine (the "control" rats). All of the control rats continued pressing levers to get more heroin, the investigators found.

Since heroin abuse and addiction also help drive the spread of HIV through needle sharing, the researchers are now exploring whether it might be possible to combine an HIV vaccine (none is currently available) and a heroin vaccine into the same injection.

The findings were released online in advance of print publication in the Journal of Medicinal Chemistry.

While the findings hold promise, experts note that research involving animals frequently fails to lead to benefits for humans.

More information

For more about drug abuse, visit the U.S. National Library of Medicine.