ABSTRACT
Kappa opioid receptors (KORs) are involved in a variety of aversive behavioral states, including anxiety. To date, a circuit-based mechanism for KOR-driven anxiety has not been described. Here, we show that activation of KORs inhibits glutamate release from basolateral amygdala (BLA) inputs to the bed nucleus of the stria terminalis (BNST) and occludes the anxiolytic phenotype seen with optogenetic activation of BLA-BNST projections. In addition, deletion of KORs from amygdala neurons results in an anxiolytic phenotype. Furthermore, we identify a frequency-dependent, optically evoked local dynorphin-induced heterosynaptic plasticity of glutamate inputs in the BNST. We also find that there is cell type specificity to the KOR modulation of the BLA-BNST input with greater KOR-mediated inhibition of BLA dynorphin-expressing neurons. Collectively, these results provide support for a model in which local dynorphin release can inhibit an anxiolytic pathway, providing a discrete therapeutic target for the treatment of anxiety disorders.
Subject(s)
Amygdala/drug effects , Anxiety , Dynorphins/pharmacology , 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer/pharmacology , Amygdala/metabolism , Animals , Behavior, Animal/drug effects , Calcium-Calmodulin-Dependent Protein Kinase Type 2/genetics , Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism , Channelrhodopsins , Evoked Potentials/drug effects , Glutamic Acid/pharmacology , Imidazoles/pharmacology , Male , Maze Learning/drug effects , Memory/drug effects , Mice , Mice, Inbred C57BL , Mice, Inbred DBA , Microscopy, Fluorescence , Patch-Clamp Techniques , Pyridines/pharmacology , Receptors, Opioid, kappa/agonists , Receptors, Opioid, kappa/genetics , Receptors, Opioid, kappa/metabolism , Septal Nuclei/physiology , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
Binge alcohol drinking is a tremendous public health problem because it leads to the development of numerous pathologies, including alcohol abuse and anxiety. It is thought to do so by hijacking brain systems that regulate stress and reward, including neuropeptide Y (NPY) and corticotropin-releasing factor (CRF). The central actions of NPY and CRF have opposing functions in the regulation of emotional and reward-seeking behaviors; thus, dysfunctional interactions between these peptidergic systems could be involved in the development of these pathologies. We used converging physiological, pharmacological and chemogenetic approaches to identify a precise neural mechanism in the bed nucleus of the stria terminalis (BNST), a limbic brain region involved in pathological reward and anxiety behaviors, underlying the interactions between NPY and CRF in the regulation of binge alcohol drinking in both mice and monkeys. We found that NPY Y1 receptor (Y1R) activation in the BNST suppressed binge alcohol drinking by enhancing inhibitory synaptic transmission specifically in CRF neurons via a previously unknown Gi-mediated, PKA-dependent postsynaptic mechanism. Furthermore, chronic alcohol drinking led to persistent alterations in Y1R function in the BNST of both mice and monkeys, highlighting the enduring, conserved nature of this effect across mammalian species. Together, these data provide both a cellular locus and signaling framework for the development of new therapeutics for treatment of neuropsychiatric diseases, including alcohol use disorders.
