Ibotenic Acid Lesions in the Bed Nucleus of the Stria terminalis Attenuate Conditioned Stress-Induced Increases in Prolactin, ACTH and Corticosterone

Abstract

The contribution of the bed nucleus of the stria terminalis (BST) to the expression of stress-induced increases in ACTH/corticosterone, prolactin and renin secretion was assessed. Neurons in the lateral part of the BST were destroyed with bilateral injections of the cell-selective neurotoxin ibotenic acid (1.5 µg in 0.1 µl of solution per side). Two weeks later, the rats were stressed using an immobilization or conditioned stress paradigm. Rats with lesions in the lateral part of the BST showed attenuated ACTH and corticosterone responses to conditioned stress. Bilateral ablation of lateral BST significantly reduced the prolactin secretory response to conditioned stress. The same lesions had no effect upon plasma increases in renin that occur in response to conditioned stress. Also, destruction of neurons in the BST did not affect immobilization-induced increases in ACTH, corticosterone, prolactin or renin. Previous studies have demonstrated that ibotenic acid lesions in the central amygdala reduce corticosterone and renin response to conditioned stress. Thus, both the BST and central amygdala are important for the adrenocortical response to conditioned stress. Neurons in the central nucleus of the amygdala are part of the circuitry that mediates renin responses to conditioned stress. Neurons in the BST are important for the full expression of prolactin responses to conditioned stress. The neuronal circuitry and stressor specificity in the mediation of prolactin, renin and ACTH/corticosterone responses are discussed.

Time-Dependent Alterations in mRNA Expression of Brain Neuropeptides Regulating Energy Balance and Hypothalamo-Pituitary-Adrenal Activity after Withdrawal from Intermittent Morphine Treatment

“…Similarly, it was reported recently that CRF expression in the CeA increases with time, after withdrawal from intermittent morphine treatment (Maj et al, 2003). Stressor inputs affect activity in the BNST and amygdala in an interactive manner, and CRF seems to play a large role in the chronic stress response network (Gray et al, 1993;Schulkin et al, 1994;Gray and Bingaman, 1996;Walker and Davis, 1997;Koob and Heinrichs, 1999;Erb et al, 2001;McNally and Akil, 2002). The changes in CRF mRNA in highly interconnected limbic structures with different durations of morphine treatment suggest that some consolidation of responses to the chronic stressor may have occurred, but additional experiments are required for precise interpretation.…”

Contextual conditioning in rats as an animal model for generalized anxiety disorder

“…A study in rats showed significantly higher plasma ACTH levels after reexposure to a conditioned context, as compared with nonshocked controls (Gray, Piechowski, Yracheta, Rittenhouse, Bethea & Van de Kar, 1993). Another study found a positive correlation between ACTH plasma levels and contextual freezing (Tiba, Oliveira, Rossi, Tufik, & Suchecki, 2008).…”

Role of the Hippocampus, the Bed Nucleus of the Stria Terminalis, and the Amygdala in the Excitatory Effect of Corticotropin-Releasing Hormone on the Acoustic Startle Reflex

“…Davis et al (1995) showed that electrolytic lesions of the BNST blocked contextual conditioning or long-term sensitization of startle when fear-potentiated startle training occurred daily but had no effect on fear-potentiated startle itself. Gray et al (1993) reported that lesions of the BNST attenuated increases in plasma levels of AC TH and corticosterone after reintroduction into a context previously paired with foot shocks.…”