Genetic cell targeting uncovers specific neuronal types and distinct subregions in the bed nucleus of the stria terminalis

Abstract

The bed nucleus of the stria terminalis (BNST) plays an important role in fear, stress, and anxiety. It contains a collection of sub-nuclei delineated by gross cytoarchitecture features; however, there has yet to be a systematic examination of specific BNST neuronal types and their associated neurochemical makeup. The present study focuses on improved characterization of the anterior BNST based on differing molecular and chemical expression aided by mouse genetics. Specific Cre driver lines crossed with a fluorescent reporter line were used for genetic cell targeting and immunochemical staining. Using this new approach, we were able to robustly identify specific excitatory and inhibitory cell types in the BNST. The presence and distribution of excitatory neurons were firmly established; glutamatergic neurons in the anterior BNST accounted for about 14% and 31% of dorsal and ventral BNST cells, respectively. GABAergic neurons expressing different isoforms of glutamic acid decarboxylase were found to have differential sub-regional distributions. Almost no parvalbumin-expressing cells were found in the BNST, while somatostatin-expressing cells and calretinin-expressing cells account for modest proportions of BNST cells. In addition, vasoactive intestinal peptide-expressing axonal plexuses were prominent in the oval and juxtacapsular (jc) subregions. In addition, we discovered that corticotropin-releasing hormone (CRH) expressing cells contain GABAergic and glutamatergic subpopulations. Together, this study reveals new information on excitatory and inhibitory neurons in the BNST, which will facilitate genetic dissection and functional studies of BNST subregions.

Characterization of the relaxin family peptide receptor 3 system in the mouse bed nucleus of the stria terminalis

“…With the exception of cerebellar Purkinje cells and the commissural nucleus, CaMKIIα does not co‐localize with glutamic acid decarboxylase (GAD) in the rodent brain, implying that CaMKIIα is predominantly expressed in non‐GABAergic neurons and is recognized as a marker for excitatory neurons (Benson et al, ; McDonald, Muller, & Mascagni, ). We noted strong CaMKIIα IR in the alBNST and to a lesser extent in the pBNST, in line with previous reports in rats (Erondu & Kennedy, ) and mice (Nguyen et al, ; Olsen et al, ).…”

“…However, no co‐localization of PV or CR in RXFP3+ cells was detected. The paucity of PV immunolabeling in the BNST is in line with previous studies (Nguyen et al, ).…”

“…We conducted double-labeling for these three different calcium-binding proteins and tdTomato (n = 4 brains examined). In agreement with previous reports (Nguyen, Dela Cruz, Sun, Holmes, & Xu, 2016), PV immunoreactivity was negligible, with sparse PV+ cell bodies present throughout the entire BNST. CR immunofluorescence in the dBNST was also sparse.…”

“…BNST, bed nucleus of the stria terminalis [Color figure can be viewed at wileyonlinelibrary.com] cells was detected. The paucity of PV immunolabeling in the BNST is in line with previous studies (Nguyen et al, 2016).…”

The Corticotropin Releasing Factor Receptor 1 in Alcohol Use Disorder: Still a Valid Drug Target?

“…The lateral capsular subregion of the CeA, which contains serotonergic inputs in both species, has a dense CRF fiber plexus in mice that is absent in rats, providing an anatomical basis for interspecies differences in CRF-serotonergic interactions in the CeA (Asan et al, 2005). In addition, CRF neurons in the mouse dorsal BNST are widely distributed and lie outside of the oval nucleus, whereas in rat they cluster in the oval nucleus (Nguyen et al, 2016, Pomrenze et al, 2015). Adding to the anatomical differences, there is evidence that BNST CRF neurons have different morphological and electrophysiological properties when compared in rat, mouse, and non-human primates (Daniel et al., 2017).…”