Noradrenergic control of the bed nucleus of the stria terminalis in stress and reward

Abstract

The bed nucleus of the stria terminalis (BNST) is a group of inter-connected subnuclei that play critical roles in stress-reward interactions. An interesting feature of this brain region is the massive noradrenergic input that it receives. Important roles for norepinephrine in this region have been documented in a number of stress and reward related behaviors. This work has been paralleled over the last several years by efforts to understand the actions of norepinephrine on neuronal function in the region. In this review, we will summarize the current state of these research areas.

Figure 1. Schematic of the actions of Norepinephrine in the BNST

Left Panel) General schematic of the BNST surrounding the anterior commissure, illustrating top-down excitatory input from regions such as the medial prefrontal cortex (mPFC), insular (Ins), hippocampus and basolateral amygdala (BLA). The region integrates this input with ascending inputs from a variety of sources, including the noradrenergic (NE) input from through the ventral noradrenergic bundle (VNAB). Right panel) Graph illustrating potential time-dependent overall actions of different NE receptor classes on BNST function. Left axis is the relative excitation or inhibition of BNST function over time, right axis is extracellular NE levels. Restraint stress is known to produce a rise in extracellular NE levels in the BNST. Data suggest that overall actions of α₂ receptors on excitatory transmission are inhibitory, and as this receptor has a higher affinity for NE than other receptors, this action could be tonic in nature. β adrenergic receptors produce a rapid enhancement of excitatory drive in the BNST. α₁ adrenergic receptors produce a biphasic action. See text for discussion.