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.
Methamphetamine use and HIV infection raise the risk for functional dependence, or the need for assistance with everyday tasks. People who use methamphetamine and are HIV positive showed the highest levels of functional dependence in most domains of daily life.
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.