The noradrenergic nucleus locus coeruleus (LC) is an important mediator of stress responses and dysfunction of this system is implicated in affective disorders such as anxiety and depression. Elevated norepinephrine levels in the extended amygdala have been implicated in heightened anxiety following withdrawal from drugs of abuse. This region receives its noradrenergic input from the A1/A2 cell groups in the caudal medulla. We are interested to know whether blockade of the mGlu5 receptor attenuates anxiety associated with protracted withdrawal from cocaine and if the anxiolytic actions of these compounds are dependent on their ability to limit increases in extracellular NE.
