Neurons of the bed nucleus of the stria terminalis (BNST). Electrophysiological properties and their response to serotonin.

A descending pathway from the bed nucleus of the stria terminalis (BNST) to nuclei within the hypothalamus and brainstem has been implicated in the generation of anxiety.1 Drugs such as the 5-HT1A agonist, buspirone, and specific serotonin reuptake inhibitors (SSRIs), which are used to treat anxiety behaviors, act to modulate serotonin (5-HT) transmission.2 Hence, 5-HT may act as a neuromodulator in the BNST to regulate anxiety states. The BNST receives serotonergic afferents from the midbrain raphé nuclei,4 and has high densities of 5-HT1-like receptors.3 Moreover, infusion of buspirone into the BNST blocks light-enhanced startle.1 It is, therefore, important to know how excitation is regulated within the BNST, and how 5-HT may affect neuronal excitation and hence signal transduction. The aim of this study was to determine the electrophysiological properties of individual neurons, and to examine the effects of serotonin on these intrinsic properties, using whole-cell patch clamp recording from BNST neurons, in vitro.