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.
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.
Driving under the influence of marijuana is a dangerous public health concern. NIDA researchers have discovered that breath expelled into a Breathalyzer-style collection device contained measurable amounts of THC for up to 2 hours after participants in a recent clinical trial smoked the drug.
Exposing rats to THC increases the likelihood that the animals will later self-administer nicotine. THC-exposed rats are also willing to work harder to obtain nicotine. When extrapolated to people, the findings suggest that THC’s pharmacological impact on the brain may make a person who uses marijuana more vulnerable to developing nicotine addiction, an underappreciated health consequence of marijuana use.