Activation of β-adrenoceptors in the bed nucleus of the stria terminalis induces food intake reduction and anxiety-like behaviors

Abstract

We previously demonstrated the critical role of noradrenergic transmission within the ventral part of the bed nucleus of the stria terminalis (vBNST) in pain-induced aversion. We showed that activation of β-adrenoceptors in this brain region by intra-vBNST injection of isoproterenol, a β-adrenoceptor agonist, produced aversive responses. In the present study, we examined the effects of a β-adrenoceptor agonist injected into the vBNST on food intake and anxiety-like behaviors in male Sprague-Dawley rats. Bilateral intra-vBNST injection of isoproterenol (3 and 10 nmol/side) caused a dose-dependent decrease in food intake; this suppressive effect was reversed by co-administration of timolol, a β-adrenoceptor antagonist. Dose-dependent (10 and 30 nmol/side) induction of anxiety-like behaviors by isoproterenol was observed in the elevated plus maze (EPM) test, which was also reversed by co-administration of timolol. Off-site control injections of isoproterenol into the lateral ventricle did not show any significant effect in the food consumption and EPM tests. These results suggest that the vBNST is one of the neuroanatomical substrates which may be involved in the close relationship between negative affective states and reduction of food intake, and that noradrenergic transmission within this brain region plays a critical role in inducing anxiety-like behaviors and reduced food intake.