Bed nucleus of the stria terminalis noradrenergic system modulates contextual fear conditionig: possible interaction with CRF and glutamatergic and nitrergic neurotransmission

Abstract

The bed nucleus of the stria terminalis (BNST) seems to be critically involved with expression of anxiety-related responses. The BNST is one of the main targets of noradrenergic innervation in the central nervous system. Moreover, some evidence showed that during aversive situations noradrenaline releases is increased in BNST. Previous studies from our laboratory showed that BNST noradrenergic neurotransmission is involved with conditioned emotional response (CER) by activation of both ±1 and ²1-adrenergic receptors. In addition, previous studies described that BNST ²1-adrenergic receptors activation increases the local release of glutamate. Moreover, this glutamate releases is dependent of CRF1 receptors. In fact, there is evidence for the involvement of BNST in stress responses mediated by CRF and the anxiogenic-like effects of CRF in BNST are mediated by CRF1 receptors. Therefore, the modulation of CER by the BNST noradrenergic system could involve the participation of other neurotransmitters; however, this possibility was not tested in BNST for contextual fear conditioning (CFC). Therefore, we believe that the BNST noradrenergic system interacts with other mediators present in BNST on the modulation of CFC. To test this hypothesis, we will have the pharmacological manipulation of CRF1 receptors, glutamate and nitrergic system. (AU)