Brain Chemical Stimulates Cocaine Craving in Animals
Hypocretin-1 provokes stress-like state that drives rats to cocaine
FRIDAY, Dec. 16 (HealthDay News) -- Brain infusions of the neuropeptide hypocretin-1 (Hcrt-1) can cause rats to seek cocaine again after being weaned from the drug, possibly by inducing a stress-like state, according to a study published online Dec. 12 in the early edition of the Proceedings of the National Academy of Sciences.
Benjamin Boutrel, Ph.D., of the University of Lausanne in Switzerland, and colleagues trained 54 rats to self-administer intravenous cocaine infusions via catheters inserted into their jugular veins, and studied their reactions to various stimuli during and after withdrawal.
The researchers found that intracerebroventricular infusions of Hcrt-1, which is normally produced by a few thousand neurons in the hypothalamus, caused the rats to seek cocaine again and dramatically elevated self-stimulation thresholds, indicating that hypocretin-1 negatively regulates the activity of brain reward circuitries.
"Here, we show that the Hcrt-1 peptide reinstates previously extinguished cocaine-seeking behavior and induces a long-lasting brain reward deficit," the authors write. "Overall, these data highlight a dynamic relationship between Hcrt and stress pathways in regulating the reinstatement of previously extinguished drug-seeking behaviors," they conclude.