COLUMBUS , Ohio – Researchers found that they could eliminate the rewarding effect of cocaine on mice by genetically manipulating a key target of the drug in the animal's brain.
While the researchers aren't suggesting that these genetic modifications be made in humans, the work brings to light the key protein that controls cocaine's effects in the body, which may help scientists develop medications that achieve the same results and therefore help addicts overcome their dependence.
Humans are not evolutionarily adapted to handle recreational drugs. But some day with genetic engineering our offspring might be adapted to resist drug and alcohol abuse.
Howard Gu and colleagues at Ohio State University showed they could genetically engineer mice to be resistant to the effects of cocaine.
He and his colleagues raised laboratory mice with genetic alterations in the gene that codes for the dopamine transporter.
“By doing so we created a dopamine transporter that resists cocaine but also retains its function of taking up dopamine and carrying it back to the neurons,” Gu said.
I am not surprised that an alteraton of a brain protein could produce a different reaction to a drug will at the same time retaining normal function. But what is amazing is that these scientists - using 2006 biotechnology - were able to find an alteration that produces this outcome.
The behavior of the mice with genetically engineered dopamine transporters suggest that they did not get a high off of cocaine
“The normal mice spent more time in the compartment where they had received the cocaine injections,” Gu said. “These animals were seeking more cocaine. However, the mice with the modified transporters showed no preference for either test compartment within the box.”
The researchers used the video footage to measure each animal's activity level after a cocaine injection. The normal mice on cocaine covered roughly five times the distance than the control mice injected with saline (6 meters vs. 1 meter). In contrast, the cocaine-injected mice with the modified dopamine receptors covered about half the distance that the saline-only injected mice covered (roughly 1.5 meters vs. 3 meters.)
“After the cocaine injections, the normal mice ran all over the place, sniffing and checking everything out in the box over and over again, until we took them out of the box,” Gu said. “But cocaine seemed to calm the modified mice, as they sat in a corner for long periods of time.”
“To the modified mice, cocaine appears to be a suppressant, not a stimulant,” Gu said.
Some people argue it will be hard to discover new ways to enhance cognitive function. But using today's biotechnology these Ohio State scientists found a way to reduce the ability of a drug to alter cognitive function. Imagine what tools will be available 20 years from now to use to search for ways to alter functionality in brain proteins.
|Share |||Randall Parker, 2006 June 04 10:46 PM Brain Addiction|