可卡因上瘾 z-bo 2020-11-02 297

　　In the recently published "Journal of Neuroscience", researchers from the South Carolina Medical University and the National Institutes of Health described how drug reminders change specific brain cells responsible for motivation, thereby increasing the desire to seek drugs. These connections with other brain cells will be strengthened, because dendritic spines are the parts of the brain cells that receive information from other neurons and expand in response to cell-to-cell communication of molecules in the brain. This enhanced connectivity increases the urge to participate in drug use and makes the possibility of relapse higher. Understanding this communication pathway may lead to more targeted treatments for drug addiction.

　　This research was led by Dr. Peter W. Kalivas, a professor in the Department of Neuroscience of MUSC, and Dr. Constanza Garcia-Keller, an assistant professor working in the Kalivas laboratory.

　　For decades, the Kalivas laboratory has been studying the mechanisms of drug addiction. In previous studies, Kalivas and his research team showed that the increase in the size of these spines is related to the degree to which the animals act on drugs such as cocaine. Interestingly, these spinous processes enlarged in response to signals not from other neurons but from the extracellular matrix surrounding these cells. They found that these signals from the outside of brain cells caused changes in neurons, which changed their connections with other neurons.

　　Kalivas explained: “The key finding is that the enlargement of the spinous process is necessary and is caused by cues related to addictive drugs, not cues related to natural rewards.”

　　This is an important difference, because it means that a variety of therapies can be developed to reduce the craving for drugs without depriving the patient of the pleasant experience.

　　Researchers were able to use high-resolution confocal microscopes to image fine images of neurons in the nucleus accumbens of the brain, an area related to drug addiction. They can see the changes in the spinous processes under different conditions, and even the signaling molecules inside the cells that cause the spine to increase in size.

　　One of these molecules in neurons is focal adhesion kinase (FAK). When Kalivas and his team suppressed the protein with a drug, the animals did not seek cocaine when prompted by exposure to the drug. In addition, they also found that the modification of the kinase and actin binding protein cofilin leads to enlargement of the spine and strengthens the connection of specific cell types in the brain. This connection is the spinous neuron-nucleus accumbens in D1. Neurons can stimulate specific behaviors.

　　Kalivas said: "There are actually two cell populations in the nucleus accumbens. One stimulates motivation and the other inhibits behavior." "Our research shows that this signal is transmitted through cell populations that promote motivational behaviors, not those responsible for inhibiting behavior. Cell population."

　　In other words, cocaine is changing the structure and function of the brain, especially in the D1 medium spiny neurons, to motivate animals to look for more cocaine.

　　A better understanding of how drugs change the structure of neurons by changing brain signals is essential for developing effective therapies to avoid recurrence.