Adrenalectomy decreases corticotropin-releasing hormone gene expression and increases noradrenaline and dopamine extracellular levels in the rat lateral bed nucleus of the stria terminalis

Abstract

The bed nucleus of the stria terminalis (BNST) has a high density of corticotropin-releasing hormone (CRH)-containing neurons that are significantly innervated by noradrenergic and dopaminergic nerve terminals. This limbic structure is involved in the extrahypothalamic response to stress. The purpose of the present work is to study whether the absence of glucocorticoids, induced by a long-term adrenalectomy, regulates CRH gene expression and noradrenaline and dopamine extracellular levels in the rat BNST. The results showed that adrenalectomy decreases CRH mRNA in the dorsal lateral BNST but not in the ventral lateral BNST. Adrenalectomy also decreases CRH-like immunoreactivity both in BNST subnuclei and in the central nucleus of the amygdala. In addition, adrenalectomy significantly increases noradrenaline and dopamine extracellular levels in the lateral BNST. The present results suggest that adrenalectomy regulates CRH gene expression and noradrenaline and dopamine extracellular levels in the BNST in an opposite way. Thus, the present study adds novel evidence further supporting that the BNST and the central nucleus of the amygdala form part of an adrenal steroid-sensitive extrahypothalamic circuit that has been involved in fear and anxiety responses and in clinical syndromes such as melancholic depression, posttraumatic stress disorders, and addiction.