Project Summary Alcohol use disorder (AUD) is characterized as an impaired ability to stop or control alcohol use, leading to compulsive intake, trouble limiting intake, and the occurrence of a negative affective state during alcohol withdrawal. Many negative symptoms arise during alcohol withdrawal, including heightened sensitivity to painful stimuli. Nearly 75% of individuals with AUD report experiencing pain as a result of their alcohol use, and many of those individuals will use alcohol to try to cope with their pain. In addition, chronic alcohol exposure contributes to the development of hyperalgesia and chronic pain in mice and rats during withdrawal. A better understanding of the mechanisms that lead to the development and maintenance of pain in AUD patients is needed. The parabrachial nucleus (PBN) projects to multiple brain areas involved in physiological processing, including the central amygdala, and this pathway is considered to be a hub for pain and aversion. Glutamatergic PBN neurons express neuropeptide Y (NPY) receptor 1 (Y1), and chronic alcohol exposure can reduce CNS Y1 expression. Additionally, our preliminary work illustrates PBN Y1 neurons project to the CeA. Y1s work to inhibit neuronal functioning and our laboratory has found that activation of Y1 receptors on PBN neurons reduces neuropathic pain-like behavior in mice. My central hypothesis is that chronic alcohol exposure increases the activity of PBN Y1 neurons, leading to sensory and affective components of chronic alcohol withdrawal induced pain (CAWIP). I predict PBN Y1 neuron activity is increased during alcohol withdrawal, and that inhibiting PBN Y1 neurons will attenuate pain associated with alcohol withdrawal. Specific Aim 1 will determine activity of PBN Y1 neurons in alcohol withdrawn mice during nociception. Specific Aim 2 will inhibit PBN Y1 neurons and pharmacologically activate PBN Y1 receptors to attenuate hypersensitivity associated with alcohol withdrawal. Conducting these experiments will elucidate the PBN Y1 circuitry that underlies CAWIP.