Ream Al-Hasani, Ph.D. - US grants

DESCRIPTION (provided by applicant): The overall goal of this research is to better understand role of dynorphin and CRF in negative affective behaviors that are associated with nicotine withdrawal. Both dynorphin and CRF systems have been shown to drive stress and aversive behaviors but few studies have determined how these systems modulate one another to drive these behaviors through the extended amygdala. Dynorphin/Kappa Opioid Receptor (KOR) activity has been known to mediate negative emotional states inducing, dysphoria, aversions, and depression. CRF also produces dysphoria, aversion and anxiety-like behavior via dynorphinergic interactions, and it has been hypothesized that the increased release of CRF may be a primary contributor in the development of anxiety disorders. Therefore, we propose to examine the role and interactions of CRF and dynorphin in the mediation of aversive behaviors and whether this in turn modulates nicotine withdrawal. This five-year project has three specific aims. In the first aim (during the K99 phase) we will determine whether dynorphin regulates aversion in the ventral NAc. The second aim (during the K99 phase) is to examine the mechanisms in which nicotine interacts with the dynorphin/kappa opioid system to regulate negative affective behaviors. Here we will determine whether stimulation of dynorphin containing neurons in the NAc mediates aversion and withdrawal behavior and whether this is KOR-dependent. In these aims we will quantify dynorphin release in the NAc following optogenetic stimulation. During the R00 independent phase (Aim 3) we will quantify dynorphin release in the NAc before and following chronic nicotine exposure. We will also optogenetically stimulate CeA- CRF containing neurons and measure dynorphin release in the NAc, to examine whether CRF regulates dynorphin release and behavior characteristic of withdrawal. Since, both CRF and dynorphin are involved in the stress response and preliminary data has shown that chronic stress can block KOR-induced drug seeking, we will also determine the role of CRF1-R/KOR interactions in reinstatement of nicotine seeking, following exposure to stress. Together this work has important therapeutic implications as it will enhance our understanding of dynorphin/CRF cell-types, neural circuits that modulate negative affective behaviors.

Project Summary The goals of this research are two fold: to better understand the role of dynorphin during fentanyl withdrawal and to develop innovative, novel approaches to allow in vivo detection of endogenously release opioids. The ability to better understand how dynorphin drives negative affect associated with drug withdrawal will be critical in reducing the incidence of relapse and overdose and allow us to consider alternative more affective long-term treatments for addiction. The US Department of Health states that 42,249 people died from overdosing on opioids in 2016, 2.1 million people had an opioid use disorder and the economic cost of this epidemic was $504 billion, but is still rising along with the number of people afflicted. The reasons for this are multifaceted, but include a deep lack of understanding of how opioids alter brain circuitry to cause analgesia- which is good, but also what happens to brain circuitry to drive addiction- which is bad. We also know that pain and addiction are co-morbid with other mental health diseases such as anxiety, depression and stress, which makes cohesive research challenging. The first aim of this proposal will directly measure in vivo changes in dynorphin levels in the nucleus accumbens during withdrawal from Fentanyl. Fentanyl is 80 times more potent than morphine in vivo; its rapid onset of action not only increases the risk of addiction but likely increases the severity of withdrawal symptoms. We will use liquid chromatography/mass spectrometry which will allow detection in sub-fmol range. The second aim focuses on the development of micro-immunoelectrodes to allow more spatiotemporally controlled detection of opioid peptide release in vivo. This technology will allow us to detect peptides changes on a second to minute timescale. The combination of these techniques will, for the first time, allow us to detect dynamic changes in opioid peptides in vivo. Importantly, this will facilitate our knowledge and ability to better treat addiction, but is also very much applicable to multiple disease states and neuropeptides biology in general.