Posts tagged methamphetamine
Articles and news from the latest research reports.
New insights could boost treatment for P addiction
A Kiwi researcher’s discovery of new ways methamphetamine can alter the brain could help the development of new drug-based therapies for addiction treatment.
In 2009, New Zealand had one of the highest rates of P users in the world, and today, more than 25,000 Kiwis were estimated to still be using the drug.
Now, new research by a Victoria of University of Wellington graduate has provided valuable insights into how the brain’s natural reward pathways are strongly stimulated following exposure to methamphetamine.
Natural Compound Mitigates Effects of Methamphetamine Abuse
Studies have shown that resveratrol, a natural compound found in colored vegetables, fruits and especially grapes, may minimize the impact of Parkinson’s disease, stroke and Alzheimer’s disease in those who maintain healthy diets or who regularly take resveratrol supplements. Now, researchers at the University of Missouri have found that resveratrol may also block the effects of the highly addictive drug, methamphetamine.
(Image: Wikipedia)
Dennis Miller, associate professor in the Department of Psychological Sciences in the College of Arts & Science and an investigator with the Bond Life Sciences Center, and researchers in the Center for Translational Neuroscience at MU, study therapies for drug addiction and neurodegenerative disorders. Their research targets treatments for methamphetamine abuse and has focused on the role of the neurotransmitter dopamine in drug addiction. Dopamine levels in the brain surge after methamphetamine use; this increase is associated with the motivation to continue using the drug, despite its adverse consequences. However, with repeated methamphetamine use, dopamine neurons may degenerate causing neurological and behavioral impairments, similar to those observed in people with Parkinson’s disease.
“Dopamine is critical to the development of methamphetamine addiction—the transition from using a drug because one likes or enjoys it to using the drug because one craves or compulsively uses it,” Miller said. “Resveratrol has been shown to regulate these dopamine neurons and to be protective in Parkinson’s disease, a disorder where dopamine neurons degenerate; therefore, we sought to determine if resveratrol could affect methamphetamine-induced changes in the brain.”
Using procedures established by Parkinson’s and Alzheimer’s disease research, rats received resveratrol once a day for seven days in about the same concentration as a human would receive from a healthy diet. After a week of resveratrol, researchers measured how much dopamine was released by methamphetamine. Researchers found that resveratrol significantly diminished methamphetamine’s ability to increase dopamine levels in the brain. Furthermore, resveratrol diminished methamphetamine’s ability to increase activity in mice, a behavior that models the hyperactivity observed in people that use the stimulant.
“People are encouraged by physicians and dieticians to include resveratrol-containing products in their diet and protection against methamphetamine’s harmful effects may be an added bonus,” Miller said. “Additionally, there are no consistently effective treatments to help people who are dependent on methamphetamine. Our initial research suggests that resveratrol could be included in a treatment regimen for those addicted to methamphetamine and it has potential to decrease the craving and desire for the drug. Resveratrol is found in good, colorful foods, and has few side effects. We all ought to consume resveratrol for good brain health; our research suggests it may also prevent the changes in the brain that occur with the development of drug addiction.”
(Source: munews.missouri.edu)
Study Suggests Possibility of Selectively Erasing Unwanted Memories
The human brain is exquisitely adept at linking seemingly random details into a cohesive memory that can trigger myriad associations—some good, some not so good. For recovering addicts and individuals suffering from post-traumatic stress disorder (PTSD), unwanted memories can be devastating. Former meth addicts, for instance, report intense drug cravings triggered by associations with cigarettes, money, even gum (used to relieve dry mouth), pushing them back into the addiction they so desperately want to leave.
Now, for the first time, scientists from the Florida campus of The Scripps Research Institute (TSRI) have been able to erase dangerous drug-associated memories in mice and rats without affecting other more benign memories.
The surprising discovery, published this week online ahead of print by the journal Biological Psychiatry, points to a clear and workable method to disrupt unwanted memories while leaving the rest intact.
“Our memories make us who we are, but some of these memories can make life very difficult,” said Courtney Miller, a TSRI assistant professor who led the research. “Not unlike in the movie Eternal Sunshine of the Spotless Mind, we’re looking for strategies to selectively eliminate evidence of past experiences related to drug abuse or a traumatic event. Our study shows we can do just that in mice — wipe out deeply engrained drug-related memories without harming other memories.”
Changing the Structure of Memory
To produce a memory, a lot has to happen, including the alteration of the structure of nerve cells via changes in the dendritic spines—small bulb-like structures that receive electrochemical signals from other neurons. Normally, these structural changes occur via actin, the protein that makes up the infrastructure of all cells.
In the new study, the scientists inhibited actin polymerization—the creation of large chainlike molecules—by blocking a molecular motor called myosin II in the brains of mice and rats during the maintenance phase of methamphetamine-related memory formation.
Behavioral tests showed the animals immediately and persistently lost memories associated with methamphetamine—with no other memories affected.
In the tests, animals were trained to associate the rewarding effects of methamphetamine with a rich context of visual, tactile and scent cues. When injected with the inhibitor many days later in their home environment, they later showed a complete lack of interest when they encountered drug-associated cues. At the same time, the response to other memories, such as food rewards, was unaffected.
While the scientists are not yet sure why powerful methamphetamine-related memories are also so fragile, they think the provocative findings could be related to the role of dopamine, a neurotransmitter involved in reward and pleasure centers in the brain and known to modify dendritic spines. Previous studies had shown dopamine is released during both learning and drug withdrawal. Miller adds, “We are focused on understanding what makes these memories different. The hope is that our strategies may be applicable to other harmful memories, such as those that perpetuate smoking or PTSD.”
(Source: scripps.edu)
Methamphetamine vaccine shows promise
Methamphetamine is one of the most addictive and thus commonly-used street drugs – according to the United Nations Office on Drugs and Crime, there are currently nearly 25 million meth addicts worldwide. Help may be on the way, however. Scientists from The Scripps Research Institute have had success in using a methamphetamine vaccine to block the effects on meth on lab rats.
The vaccine works by allowing the body’s immune system to attack methamphetamine molecules in the bloodstream, keeping them from entering the nervous system. This keeps the meth from affecting the user’s brain, and thus removes the incentive for using the drug.
Ordinarily, meth molecules are too small to evoke an antibody response from the body. The vaccine, known as M6, gets around this by linking a meth-related chemical to a larger carrier molecule that does cause an antibody response. Once the antibodies are in the bloodstream, they attack both the carrier molecules and the actual meth molecules.
In tests on rats, M6 blocked two of the typical effects of the drug – loss of the ability to regulate body temperature, and in increase in physical activity. In another ongoing Scripps study, meth-targeting antibodies were grown in cultured cells in a lab, then injected into rats in a concentrated dose. This approach also blocked the effects of the drug.
More animal trials are planned for now, with the possibility of human trials occurring in the future.
Fruit Flies On Methamphetamine Die Largely as a Result of Anorexia
The abuse of methamphetamine can have significant harmful side effects in humans. It burdens the body with toxic metabolic byproducts and weakens the heart, muscles and bones. It alters energy metabolism in the brain and kills brain cells.
Previous studies have shown that the fruit fly Drosophila melanogaster is a good model organism for studying the effects of methamphetamine on the body and brain. Researchers have found that meth exposure has similar toxicological effects in fruit flies and in humans and other mammals.