Increased AVP activity might be expected as a result of enhanced AVP gene expression, and may be partially responsible for the drug-seeking action in rats triggered by foot shock stress. In support of this idea, our previous study has demonstrated that selective blockade of V1b receptors blunted stress-induced heroin-seeking behavior [16]. Also, activation of V1b receptor pathways in the amygdala has been found to be an important step in the neurobiology of stress-related behaviors [15, 34] and alcohol dependence in rodent models [35]. Both the Me/BLA and central nucleus of the amygdala receive noradrenergic (NA) projections that are sensitive to stress and to adrenergic manipulations [36, 37]. Also, blockade of beta NA receptors within the central amygdala block stress-induced reinstatement [24]. Thus, although this tentative interpretation requires additional investigation, our data suggests that the NA-AVP interaction within the amygdala may be involved in individual differences in heroin-seeking precipitated by stress.
