Anel A Jaramillo - US grants

PROJECT SUMMARY/ABSTRACT All drugs of abuse produce unique interoceptive/subjective (i.e., discriminative stimulus) effects that can impact drug-taking, seeking, and relapse in both clinical and preclinical studies. However, the neural circuitry modulating the interoceptive effects of alcohol has yet to be established. The nucleus accumbens core (AcbC), a region known to mediate alcohol-related behaviors, also plays a central role in modulating the discriminative stimulus effects of alcohol. Therefore, to begin to establish the circuitry modulating the interoceptive effects of alcohol, two brain regions with projections to the AcbC will be the focus of the proposed studies: the insular cortex (IC) and the rhomboid/reuniens ventral midline thalamic nuclei (RhRe). Despite the implicated role of the IC in processing interoceptive cues and responding to alcohol-related cues, its functional role in modulating alcohol-induced interoceptive effects has not been investigated to date. Additionally, the RhRe are proposed to modulate inhibition, behavior flexibility, and motivation, but their role in modulating any drug-related behaviors has yet to be determined. However, our preliminary data demonstrate that chemogenetic inactivation of the IC increases sensitivity to alcohol and pharmacological inactivation of IC and RhRe (independently) results in partial ?alcohol-like? interoceptive effects, thus implicating a functional role for the IC and RhRe in modulating the discriminative stimulus effects of alcohol. Therefore, by investigating the two novel brain regions (IC and RhRe) and their projections to the AcbC, this application proposes to investigate the neural circuitry underlying alcohol-induced interoceptive states. Using drug discrimination methods, rats will be trained to discriminate alcohol vs. water, and we will chemogenetically inactivate the brain regions and their specific incoming AcbC projections to examine whether sensitivity to alcohol is altered. Thus, experiments in Aim 1 will determine whether IC and its projections to the AcbC modulate the discriminative stimulus effects of alcohol. Aim 2 will use a similar approach to determine the role of RhRe and its projections to the AcbC. Together these experiments will demonstrate a functional role for two novel brain regions in modulating the interoceptive effects of alcohol, while identifying potential AcbC-related neural circuitry. By conducting these experiments in parallel, this innovative approach has the ability to inform the alcohol field of regions not previously implicated or understudied while demonstrating the importance and neurobiology underlying alcohol interoceptive states/internal cues, thus helping bridge the clinical and preclinical fields.

PROJECT SUMMARY/ABSTRACT Abstinence from alcohol use induces a negative affective state that can lead to maladaptive responses to stress and relapse. Preclinical studies have begun to identify neurocircuits and peptide targets that regulate negative affect during abstinence. As the field has begun to develop a deeper understanding of the circuitries participating in addiction and negative affect, the next step is to understand how communication within these circuits is modulated particularly at the neuropeptide and microcircuit level. The bed nucleus of the stria terminalis (BNST) is a fundamental component of abstinence-relevant neurocircuitry as it modulates stress and alcohol-related behavior in a neuropeptide-dependent manner. To investigate peptide-specific BNST circuitry modulating negative-affect during abstinence, we will focus on afferents from the parabrachial nucleus (PBN), a brainstem region that functions as a danger signal. PBN projections to the BNST release calcitonin gene- related peptide (CGRP) and pituitary adenylate cyclase activating polypeptide (PACAP), peptides that modulate pain and fear circuits, respectively. Our studies implicate heterogenous and sexually dimorphic control within the PBNàBNST circuit as PBN projections induce heterogeneous ex vivo activity in BNST cells and female-specific anxiety-like behavior with BNSTPBN activation. Furthermore, our preliminary studies suggest a role for the PBN in alcohol-withdrawal, as inactivation is anxiolytic following alcohol exposure. This proposal will significantly build on this foundational evidence by investigating how CGRP and PACAP contribute to PBNàBNST circuit induced abstinence-induced behavior, in vivo and ex vivo activity. Accordingly, the mentored K99 phase will build on my in vivo fiber photometry recordings and provide training in ex vivo recordings to determine the role of CGRP on BNSTàPBN activity, abstinence-induced behavior (AIM1), and the contribution of PACAP on the CGRP-neuromodulation (AIM2). The independent R00 phase will investigate the role of PACAP on BNSTàPBN at the microcircuit level and alcohol-related states, with the goal to further delineate the intricacies of peptide crosstalk (AIM3). The proposed studies and related career development training plan in this MOSAIC Pathway to Independence Award collectively provide the ideal mechanism to transition the applicant to a career as an independent addiction neuroscientist. The results will significantly advance our understanding of neurocircuit mechanisms at the peptide and microcircuit level in protracted abstinence while informing the use of peptidergic pharmacotherapies in alcohol use disorders.