Investigators have shown that 2-AG, an endocannabinoid (i.e., a cannabinoid manufactured within the body, as opposed to plant-derived), augments the cocaine-induced dopamine surge in the brain’s reward system.
The discovery adds to evidence that inhibiting activity in the endocannabinoid system might reduce cocaine’s rewarding and addictive effects.
Drugs can alter the way people think, feel, and behave by disrupting neurotransmission, the process of communication between brain cells. This article discusses the central importance of studying drugs’ effects on neurotransmission and describes some of the most common experimental methods used in this research.
New studies show that two novel compounds powerfully suppressed animals’ pain responses, while producing little or none of the respiratory depression and liability for misuse and abuse associated with morphine and other typical opioids.
Researchers monitored the activity of two types of neurons in mice: “urge” neurons, which promote feelings of reward and repeating behaviors that have produced rewards, and “control” neurons, which dampen those feelings and inhibit behavior.
A new study proposes that research into the discrete roles played by the brain’s two hemispheres could yield important and actionable insights into drug use and addiction. Evidence indicates that two risk factors for substance use, impulsivity and craving, primarily reflect activity in the right and left hemispheres, respectively.
A brain imaging study strongly suggests that regular users of marijuana have smaller orbitofrontal cortex (OFC) volumes. Such a deficit could make it more difficult to change counterproductive behaviors, including drug use.
Giving mice a modified version of a naturally occurring gene blocks cocaine’s stimulant effects without affecting the animals’ physiological or metabolic health. The new evidence advances the proposed therapy a step closer to readiness for testing in people.
Young adults who had been maltreated as children differed from others who had not been maltreated in the connectivity of nine cortical regions. The differences could compromise the maltreated group’s basic social perceptual skills, ability to maintain a healthy balance between introversion and extroversion, and ability to self-regulate their emotions and behavior.
Two researchers share their reasons for researching transcranial magnetic stimulation (TMS) for treating cocaine addiction, and describe challenges to moving forward this potentially promising therapy.
In mice, a cocaine-induced imbalance in the activity of two key populations of neurons in the reward system persists for a longer period after repeated exposure to the drug. For long-term users, this change could both weaken the cocaine “high” and strengthen the compulsion to seek the drug.
A NIDA-supported study has found that a cocaine-addicted person’s chance of managing 1 whole year of abstinence correlates with activity levels in these impaired motivational and decision-making brain areas.
A stressed rat will seek a dose of cocaine that is too weak to motivate an unstressed rat. Researchers traced the physiological pathway that links stress and the stress hormone corticosterone to increased dopamine activity and heightened responsiveness to cocaine.
Can marijuana use put offspring at heightened risk for opiate addiction, even if the use stops before the offspring are conceived? Results from a recent NIDA-funded study are consistent with other studies suggesting that a parent’s history of drug use, even preconception, may affect a child’s brain function and behavior.
Dr. Paul E. M. Phillips spoke on “Phasic Dopamine Transmission During Substance Abuse,” describing investigations that he has led into the role of brief, seconds-long bursts of dopamine signaling in addictive processes. Dr. Rita Z. Goldstein spoke on “Targeting the Brain, Cognition, and Motivation for Intervention in Addiction.”
The Scientific Director of NIDA’s Intramural Research Program talks about switching off animals’ compulsive cocaine seeking by optogenetically activating the prefrontal cortex, and the implications of this work for people. In an accompanying podcast, Dr. Bonci walks viewers through experiments that showed that prefrontal cortex activity levels may constitute a simple switch controlling whether or not animals compulsively seek cocaine.
Two recent studies suggest that genotyping may enable clinicians to base therapies on individual patients’ potential responsiveness to opioid drugs’ therapeutic effects and vulnerability to their harmful effects.
A brain response occurs in the nucleus accumbens when rats encounter a cue that they associate with previous cocaine self-administration, but not a cue associated with a pleasurable non-drug experience. Moreover, the response correlates in time and intensity with the animals’ cue-induced relapse to cocaine-seeking.
One of NIDA’s goals is to try to understand the individual differences that contribute to whether or not someone who takes a drug will become addicted to it. Dr. Rutter’s research focuses on three types of differences: Environmental, developmental, and genetic and epigenetic.
Methamphetamine alters brain structures involved in decision-making and impairs the ability to suppress habitual behaviors that have become useless or counterproductive. The two effects were correlated, indicating that the structural change underlies the decline in mental flexibility.
Ketoprofen, an anti-inflammatory agent commonly prescribed to treat arthritis, reduces neuronal damage in rats that have been exposed to chronic stress and methamphetamine. If this finding of a recent NIDA-supported study extrapolates to humans, anti-inflammatory medications may gain a place in the treatment of methamphetamine addiction.
Researchers have shut down laboratory rats’ compulsive cocaine seeking by stimulating an area of the animals’ prefrontal cortex. The finding raises the possibility that stimulating neurons in this brain area may weaken or break cocaine’s grip on the behavior of people who are addicted to the drug.
A meta-analysis of 13 genome-wide association studies of African Americans’ smoking patterns confirms the significance of genetic variation in region 15q25.1. The analysis also tentatively implicates several genome locations that have not previously been associated with smoking behaviors.
Dr. Marilyn Huestis of NIDA’s Intramural Research Program talks about conducting research on drug effects with human subjects, developing tests to help law enforcement identify drugged drivers, and an assay to help identify children whose prenatal exposure to anti-HIV drugs may put them at risk for adverse developmental outcomes.
New research demonstrated that, in rhesus monkeys, ongoing cocaine exposure weakens two brain functions that people require for successful behavioral change: cognitive flexibility and memory. But the study determined that these changes may not be permanent.
Clinical trials of N-acetylcysteine to help people recovering from drug abuse avoid relapse have demonstrated only moderate efficacy. New NIDA-supported research shows that while a low dose of the medication activates receptors associated with lowered drug-seeking behavior, a higher dose appears to activate receptors associated with increased drug-seeking behavior. The result suggests that a medication or combination of medications that stimulate the receptor GluR2/3 and block mGluR5 may work better than N-acetylcysteine alone.
The immune system has an extraordinary ability to recognize compounds foreign to the body and eliminate them. NIDA-sponsored scientists are working to harness this ability to create vaccines that will protect individuals against the psychogenic and addictive effects of abused drugs. This animation shows one of the most promising strategies, which has already yielded partial success in producing effective vaccines against nicotine, cocaine, and other drugs.
Dr. J. David Jentsch is the recipient of the 2011 Jacob P. Waletzky Memorial Award for Innovative Research in Drug Addiction and Alcoholism. Dr. Jentsch and colleagues at the University of California, Los Angeles, are studying genetic and neurochemical factors that influence individual differences in inhibitory control.
New research establishes that benzodiazepines cause addiction in a way similar to that of opioids, cannabinoids, and the club drug GHB. The discovery opens the door to designing new benzodiazepines that counteract anxiety but are not addictive.
New research suggests that differences in tobacco consumption reflect, in part, differences in the functional efficacy of a specific type of receptor in a pathway of the brain. In animal studies, nicotinic acetylcholine receptors with the α5 subunit played a key role in producing aversive responses to nicotine, thereby dissuading further consumption of the drug.
In a new series of studies tracing the molecular events that occur in the brain as memories are formed and preserved, researchers find that certain epigenetic changes may promote vulnerability to relapse.
Describes research findings that show that chronic cocaine abuse may change the production of many proteins in the neurons of the brain’s reward system, aiding in our understanding how the drug causes addiction.
Reports on an evaluation of the Chief Resident Immersion Training (CRIT) program to assess its effectiveness in improving knowledge, confidence, and preparedness to diagnose, manage, and teach about substance abuse.
Describes research results reporting that people who favor novelty have lower-than-average availability of a receptor that inhibits dopamine's release from neurons, which likely stimulates the activity of reward circuits.
Describes a literature analysis reporting on the prevalence of people with bipolar disorder who also have a substance use disorder and discusses the genetic link that may contribute to this comorbidity.
Describes research findings demonstrating that the immune system participates in the shaping of brain circuits during a child's development, a finding that may shed light on the origins of neurodegenerative diseases.
Reports on research showing that the neurons that deliver dopamine to two regions of the brain's mesolimbic reward system respond differently to opioids, an important finding for drug treatment research.