A group of researchers at National Institute on Alcohol Abuse and Alcoholism have found that the brain system triggering stress and anxiety could be explored as a possible therapeutic target for reducing alcoholism.
Previous studies have shown that a brain chemical known as Substance P (SP) is released in response to stress, produces symptoms of anxiety, and binds preferentially to NK1R.
SP and NK1R are highly expressed in brain areas involved in stress responses and drug reward.
Both pre-clinical and clinical trials have demonstrated that brain molecule, neurokinin 1 receptor, or NK1R appears to play a crucial role in stress-related drinking and deactivating the molecule can significantly reduced alcohol consumption.
The laboratory trials have shown that genetically engineered mice lacking NK1 receptors consumed much less alcohol than normal mice with fully functional NK1R.
Consequently, clinical studies showed that an experimental compound designed to block NK1 receptors reduced alcohol craving and improved overall well-being among recently detoxified alcohol-dependent individuals with high levels of anxiety.
With the help of functional brain imaging, the researchers showed that the augmented sensitivity to negative stimuli seen in alcoholics was reduced with the medication.
"The driving force behind dependent individuals' alcohol use transitions from what we call reward craving to relief craving," said Dr. Heilig.
"By the time people seek treatment for alcoholism, the pleasurable or rewarding effects of the drug are gone for most patients. Instead, alcohol-dependent individuals often feel low, anxious and are sensitive to stress, and they use alcohol to relieve these bad feelings," he added.
"These findings advance our understanding of the link between stress and alcohol dependence and raise the prospect of a new class of medications for treating alcoholism," said NIAAA Director Ting-Kai Li.
The study is reported online in Science Express.