Prolonged cocaine use affects the expression of genes and proteins in the nucleus accumbens (NAc), a region of the brain involved in many reward-related behaviours such as drug use. The findings were published on October 9 in the open-access journal Science Advances.

The researchers from the State University of New York at Buffalo trained adult male rats to self-administer cocaine during ten days; one group had cocaine available for short periods of time, while the other had extended access. Next, they set out to examine the differences in the NAc areas of the two rat groups.

Craving and relapse

The team found that the expression of the INO80, a protein that plays a part in remodelling the DNA structure and, eventually, in controlling gene expression, is increased in the NAc of rats who experienced prolonged use of cocaine but not in rats who used the drug for shorter periods.

The investigators also found that INO80 expression increased after thirty days of abstinence but not on abstinence day one, thus confirming the hypothesis that cocaine craving intensifies over a period of abstinence.

The novelty of this study, according to David M. Dietz, senior author of the paper, is that “it begins to reveal what happens on a cellular basis, what genes are turned on and off during a prolonged period of abstinence”.

References:

Werner C, Mitra S, Martin J et al. Ubiquitin-proteasomal regulation of chromatin remodeler INO80 in the nucleus accumbens mediates persistent cocaine craving. Published 2019. Accessed October 10, 2019. [OPEN ACCESS]

Image Credit: Marco Verch / Flickr

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