Lots of interesting stuff here on new treatments for addiction, including: A methadone (heroin-substitute) replacement called buprenorphine with less dependency and less of a high; an injectible version of alcoholism treatment naltrexone called Vivitrol, which is injectable and lasts one month; some medications that increase GABA production; and, perhaps most innovative is a vaccine against nicotine that allows antibodies to bind nicotine and prevent crossing through the blood-brain barrier.
Excerpts with some of the neat experiments involving dopamine receptors and environmental factors in addiction are after the jump.
On the role of D2 receptors in addiction:
In one experiment, Volkow increased the level of dopamine D2 receptors in rats that had low levels. After the increase, the rats significantly curtailed their intake of alcohol, which they had eagerly gulped down before. Unfortunately, we don’t yet know how to safely increase the number of dopamine D2 receptors in humans.
And remember the dopamine D2 receptors that some hypothesize may protect us from abusing drugs? There is evidence that our environment can affect those, too. In 2003, researchers at the Wake Forest School of Medicine measured the levels of dopamine D2 receptors of 20 macaque monkeys while they were housed in isolation. They then assigned the monkeys to social groups of four monkeys each, letting natural social hierarchies develop. Three months later, they tested the levels of D2 receptors again.
The dominant monkeys — who, the theory goes, were much less stressed and anxious than the subordinate ones — had 20 percent higher D2 receptor function, while the submissive ones were unchanged. The monkeys were then taught how to self-administer cocaine by pressing a lever, with researchers finding that the dominant monkeys took significantly less cocaine than the subordinate ones.
Interestingly, though, when the animals that seemed to be protected from addiction were given cocaine repeatedly, the number of their D2 receptors eventually went down, and they then became addicted. The moral of the monkey story, Volkow says, is that environment — if good or bad enough — can sometimes trump genetics and biology.
I found this idea of addiction prevention through an enriched environment fascinating:
[Bruce] Alexander [at Simon Fraser University] is among a vocal group of addiction researchers who argue that focusing on a pill to treat addicts fails to address the primary cause of becoming and staying hooked: our unhappy, disconnected lives. Beginning in the late 1970’s, Alexander and his team of researchers at Simon Fraser set out to study the role of our environment on addictive behavior. Until that point, most scientists studying addiction put rats in small, individual cages and watched as they eagerly guzzled drug-laced solutions and ignored water and food, sometimes dying in the process. This phenomenon was noted — first by researchers, then drug czars, then parents trying to keep their children off drugs — as proof of the inherently addictive quality of drugs and of the inevitable addiction of any human who used them. This was false, of course. Most people who use drugs don’t become addicted.
So what made all those lab rats lose their minds? Bruce Alexander and his research team had a rather simple hypothesis: The rats had awful lives. They were stressed, lonely, bored and looking to self-medicate. To prove it, Alexander created a lab-rat heaven he called Rat Park. The 200-square-foot residence featured bright balls and tin cans to play with, painted creeks and trees to look at and plenty of room for mating and socializing.
Alexander took 16 lucky rats and plopped them into Rat Park, where they were offered water or a sweet, morphine-based cocktail (rats love sweets). Alexander offered the same two drinks to the control group of rats he left isolated in cages. The results? The rat-parkers were apparently having too much fun to bother with artificial highs, because they hardly touched the morphine solution, no matter how sweet Alexander and his colleagues made it. The isolated and arguably depressed rats, on the other hand, eagerly got high, drinking more than a dozen times the amount of the morphine solution as the rats in paradise.