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NK1R
Neurokinin-1 receptor
Researchers with the National Institutes of Health already knew that the drug in question neutralizes the action of a protein called NK1R (short for neurokinin-1 receptor), which is involved in the stress response in the brain. The first hint that the drug might be useful in cutting alcohol cravings surfaced when the investigators noticed that mice who didn't have NK1R seemed to have less desire to consume alcohol.
Ref. https://abcnews.go.com/Health/Drugs/story?id=4291394&page=1