Researchers at the University of Alabama at Birmingham have discovered that the protein reelin serves as a marker for neurons activated by cocaine in the brain’s nucleus accumbens, a region critical to motivation and addiction. Published in Science Advances, their study reveals that reelin not only identifies these neurons but also plays a pivotal role in cocaine-induced behavioral and cellular changes. The findings could open new avenues for targeted treatments for cocaine use disorder.
Cocaine activates only 10 to 20 percent of neurons in the nucleus accumbens, yet this small population drives significant changes in gene expression, neural circuitry, and behavior. Using single-nucleus RNA sequencing, the team found that over 80 percent of these activated neurons expressed reelin mRNA at levels ten times higher than non-activated neurons.
To investigate reelin’s role, the researchers employed a CRISPR interference strategy to reduce its expression in rats. This knockdown altered gene activity linked to cocaine response, disrupted neuronal excitability, and diminished behaviors associated with cocaine reward, such as increased movement and place preference. Notably, it also reduced the rats’ self-administration of cocaine.
Dr. Jeremy Day’s team highlighted reelin’s unexpected prominence in this process, given its known roles in brain development and synaptic plasticity. The study suggests that reelin enables neurons to respond to cocaine by initiating long-term functional changes.
“Reelin is essential for the cellular and behavioral effects of cocaine,” said Kasey Brida, lead author of the study. “Targeting the reelin signaling pathway could offer a precise therapeutic strategy for addiction.”
The study underscores reelin’s dual role as a biomarker and regulator of cocaine-activated neurons, providing a potential target for future treatments. Further research could explore how modulating reelin signaling might mitigate addiction-related behaviors in humans.
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