Neurogenesis of the sexually dimorphic vasopressin cells of the bed nucleus of the stria terminalis and amygdala of rats

Abstract

The bed nucleus of the stria terminalis (BNST) and centromedial amygdala share many neuroanatomical and neurochemical characteristics, suggesting similarities in their development. Here we compare the neurogenesis of a group of cells for which already several common characteristics have been documented, that is, the sexually dimorphic arginine vasopressin‐immunoreactive (AVP‐ir) cells of the BNST and amygdala. To determine when these cells are born, pregnant rats received intraperitoneal injections of the thymidine analogue bromo‐2‐deoxy‐5‐uridine (BrdU) on one of nine embryonic days, E10 to E18; E1 being the day that a copulatory plug was found. At 3 months of age, the offsprings of these females were killed and their brains stained immunocytochemically for BrdU and AVP. Most AVP‐ir cells were labeled with BrdU by injections on E12 and E13. Although BrdU labeling of AVP‐ir cells did not differ between the BNST and amygdala, it differed between males and females. From E12 to E13, the percentage of BrdU‐labeled AVP‐ir cells decreased more in males than in females. AVP‐ir cells appeared to be born earlier than most other cells in the same area, the majority of which were labeled with BrdU by injections on E14, E15, and E16. The similarities in the birthdates of AVP‐ir cells in the BNST and amygdala may help to explain why these cells take on so many similar characteristics. The sex difference in birthdates of AVP‐ir cells may help to explain which cellular processes underlie the sexual differentiation of these cells. © 1996 John Wiley & Sons, Inc.

Estrogen Masculinizes Neural Pathways and Sex-Specific Behaviors

“…An equivalent number of cells expresses aromatase in both sexes in the BNST and MeA at P1, whereas there are more βgal positive cells in these regions in males compared to females at P14 (Figure 5A–E, and data not shown). Neurons in the BNST and MeA are born prenatally in rodents (al-Shamma and De Vries, 1996; Bayer, 1980), and we therefore asked if the sexual dimorphisms in these regions resulted from sex specific apoptosis. We labeled apoptotic nuclei in the neonatal BNST and MeA with the TUNEL assay.…”

The Androgen Receptor Governs the Execution, but Not Programming, of Male Sexual and Territorial Behaviors

“…We show here that the masculinization of AR expression in the BNST and POA, two limbic regions previously implicated in sexual and territorial behaviors, is controlled by estrogen signaling. This postnatal sexual differentiation of AR is unlikely to result from estrogen regulated neurogenesis as neurons that populate these regions are born prenatally (al-Shamma and De Vries, 1996; Bayer, 1980; Bayer and Altman, 1987). Previous work has implicated dimorphic apoptosis as playing a critical role in the sexual differentiation of the BNST, POA, and other brain regions (Arai et al, 1996; Davis et al, 1996; Forger, 2009; Holmes et al, 2009; Waters and Simerly, 2009; Wu et al, 2009).…”

Sexually dimorphic effects of a prenatal immune challenge on social play and vasopressin expression in juvenile rats

“…Differences in birth date of AVP neurons may contribute to differences in LPS effects on various AVP-expressing brain regions in this study. AVP neurons in the BST and MeA are born on embryonic days 11 and 12 [42,43] and therefore all of these cells could be affected by LPS treatment on embryonic day 15. In contrast, SCN cells are born on embryonic days 14–17 [44], which is, by and large, at or after the LPS treatment given in this paper.…”