Oral fentanyl consumption and withdrawal impairs fear extinction learning and enhances basolateral amygdala principal neuron excitatory-inhibitory balance in male and female mice.

The number of opioid overdose deaths has increased over the past several years, mainly driven by an increase in the availability of highly potent synthetic opioids, like fentanyl, in the un-regulated drug supply. Over the last few years, changes in the drug supply, and in particular the availability of counterfeit pills containing fentanyl, have made oral use of opioids a more common route of administration. Here, we used a drinking in the dark (DiD) paradigm to model oral fentanyl self-administration using increasing fentanyl concentrations in male and female mice over 5 weeks.

Ethanol self-administration targets GluA2-containing AMPA receptor expression and synaptic activity in the nucleus accumbens in a manner that drives the positive reinforcing properties of the drug.

Rationale: The positive reinforcing effects of alcohol (ethanol) drive repetitive use and contribute to alcohol use disorder (AUD). Ethanol alters the expression of glutamate AMPA receptor (AMPAR) subunits in reward-related brain regions, but the extent to which this effect regulates ethanol's reinforcing properties is unclear.

Objective: This study investigates whether ethanol self-administration changes AMPAR subunit expression and synaptic activity in the nucleus accumbens core (AcbC) to regulate ethanol's reinforcing effects in male C57BL/6 J mice.

Diversity of ancestral brainstem noradrenergic neurons across species and multiple biological factors.

The brainstem region, locus coeruleus (LC), has been remarkably conserved across vertebrates. Evolution has woven the LC into wide-ranging neural circuits that influence functions as broad as autonomic systems, the stress response, nociception, sleep, and high-level cognition among others. Given this conservation, there is a strong possibility that LC activity is inherently similar across species, and furthermore that age, sex, and brain state influence LC activity similarly across species.

Xylazine is an agonist at kappa opioid receptors and exhibits sex-specific responses to opioid antagonism.

Xylazine is in the unregulated drug supply at increasing rates, usually combined with fentanyl, necessitating understanding of its pharmacology. Despite commentary from politicians, and public health officials, it is unknown how xylazine impacts naloxone efficacy, and. few studies have examined it alone.

β-arrestin-biased Allosteric Modulator of Neurotensin Receptor 1 Reduces Ethanol Drinking and Responses to Ethanol Administration in Rodents.

Alcohol use disorders (AUDs) impose an enormous societal and financial burden, and world-wide, alcohol misuse is the 7 leading cause of premature death. Despite this, there are currently only 3 FDA approved pharmacological treatments for the treatment of AUDs in the United States. The neurotensin (Nts) system has long been implicated in modulating behaviors associated with alcohol misuse.

GABA release from central amygdala neurotensin neurons differentially modulates ethanol consumption in male and female mice.

The central nucleus of the amygdala is known to play key roles in alcohol use and affect. Neurotensin neurons in the central nucleus of the amygdala have been shown to regulate alcohol drinking in male mice. However, little is known about which neurotransmitters released by these cells drive alcohol consumption or whether these cells drive alcohol consumption in female mice.

Reducing the harms of xylazine: clinical approaches, research deficits, and public health context.

Objectives: Xylazine has emerged as a consistent part of the unregulated drug supply in recent months. We discuss major domains of xylazine's harm, current knowledge deficits, clinical and harm reduction strategies for minimizing harm, and xylazine's public health and policy context. As an interdisciplinary team from across the USA, we have pooled our knowledge to provide an overview of xylazine's current and emerging contexts.

GABA Release From Central Amygdala Neurotensin Neurons Differentially Modulates Reward and Consummatory Behavior in Male and Female Mice.

The central nucleus of the amygdala is known to play key roles in alcohol use and affect. Neurotensin neurons in the central nucleus of the amygdala have been shown to regulate alcohol drinking in male mice. However, little is known about which neurotransmitters released by these cells drive alcohol consumption or whether these cells drive alcohol consumption in female mice.

Neurotensin and energy balance.

The neurotensin system spans across the central nervous system, to the enteric nervous system (gut), and the periphery to govern behaviors and physiological responses that tune energy balance to maintain homeostasis. Neurotensin transmission is not only modulated by metabolic signals, neurotensin transmission itself can also impact metabolic state by exerting control over consumption, physical activity, and satiety signals. Many responses to sensory experiences and sleep processes are dictated by neurotensinergic activity via mechanisms that allow the organism to balance energy seeking and utilization to thrive in its environment.

All Hands on Deck: We Need Multiple Approaches To Uncover the Neuroscience behind the Opioid Overdose Crisis.

Opioid use disorder (OUD) affects millions of people throughout the United States, yet there are only three Food and Drug Administration-approved pharmacological treatments. Though these treatments have been shown to be effective, the number of overdose deaths continues to rise. The increase of fentanyl, fentanyl analogs, and adulterants in the illicit drug supply has further complicated treatment strategies.

Probing different paradigms of morphine withdrawal on sleep behavior in male and female C57BL/6J mice.

Opioid misuse has dramatically increased over the last few decades resulting in many people suffering from opioid use disorder (OUD). The prevalence of opioid overdose has been driven by the development of new synthetic opioids, increased availability of prescription opioids, and more recently, the COVID-19 pandemic. Coinciding with increases in exposure to opioids, the United States has also observed increases in multiple Narcan (naloxone) administrations as a life-saving measures for respiratory depression, and, thus, consequently, naloxone-precipitated withdrawal.

Chronic Ethanol Exposure Modulates Periaqueductal Gray to Extended Amygdala Dopamine Circuit.

The bed nucleus of the stria terminalis (BNST) is a component of the extended amygdala that regulates motivated behavior and affective states and plays an integral role in the development of alcohol-use disorder (AUD). The dorsal subdivision of the BNST (dBNST) receives dense dopaminergic input from the ventrolateral periaqueductal gray (vlPAG)/dorsal raphe (DR). To date, no studies have examined the effects of chronic alcohol on this circuit.

Probing different paradigms of morphine withdrawal on sleep behavior in male and female C57BL/6J mice.

Unlabelled: Opioid misuse has dramatically increased over the last few decades resulting in many people suffering from opioid use disorder (OUD). The prevalence of opioid overdose has been driven by the development of new synthetic opioids, increased availability of prescription opioids, and more recently, the COVID-19 pandemic. Coinciding with increases in exposure to opioids, the United States has also observed increases in multiple Narcan (naloxone) administrations as life-saving measures for respiratory depression, and, thus, consequently, naloxone-precipitated withdrawal.

Tauopathy and alcohol consumption interact to alter locus coeruleus excitatory transmission and excitability in male and female mice.

Alcohol use disorder is a major public health concern in the United States. Recent work has suggested a link between chronic alcohol consumption and the development of tauopathy disorders, such as Alzheimer's disease and frontotemporal dementia. However, relatively little work has investigated changes in neural circuitry involved in both tauopathy disorders and alcohol use disorder.

Noradrenergic circuits and signaling in substance use disorders.

The central noradrenergic system innervates almost all regions of the brain and, as such, is well positioned to modulate many neural circuits implicated in behaviors and physiology underlying substance use disorders. Ample pharmacological evidence demonstrates that α, α, and β adrenergic receptors may serve as therapeutic targets to reduce drug -seeking behavior and drug withdrawal symptoms. Further, norepinephrine is a key modulator of the stress response, and stress has been heavily implicated in reinstatement of drug taking.

Calcium-permeable AMPA receptor activity and GluA1 trafficking in the basolateral amygdala regulate operant alcohol self-administration.

Addiction is viewed as maladaptive glutamate-mediated neuroplasticity that is regulated, in part, by calcium-permeable AMPA receptor (CP-AMPAR) activity. However, the contribution of CP-AMPARs to alcohol-seeking behavior remains to be elucidated. We evaluated CP-AMPAR activity in the basolateral amygdala (BLA) as a potential target of alcohol that also regulates alcohol self-administration in C57BL/6J mice.

Periaqueductal gray/dorsal raphe dopamine neurons contribute to sex differences in pain-related behaviors.

Sex differences in pain severity, response, and pathological susceptibility are widely reported, but the neural mechanisms that contribute to these outcomes remain poorly understood. Here we show that dopamine (DA) neurons in the ventrolateral periaqueductal gray/dorsal raphe (vlPAG/DR) differentially regulate pain-related behaviors in male and female mice through projections to the bed nucleus of the stria terminalis (BNST). We find that activation of vlPAG/DR neurons or vlPAG/DR terminals in the BNST reduces nociceptive sensitivity during naive and inflammatory pain states in male mice, whereas activation of this pathway in female mice leads to increased locomotion in the presence of salient stimuli.

Neurotensin in reward processes.

Neurotensin (NTS) is a neuropeptide neurotransmitter expressed in the central and peripheral nervous systems. Many studies over the years have revealed a number of roles for this neuropeptide in body temperature regulation, feeding, analgesia, ethanol sensitivity, psychosis, substance use, and pain. This review provides a general survey of the role of neurotensin with a focus on modalities that we believe to be particularly relevant to the study of reward.

Manipulations of Central Amygdala Neurotensin Neurons Alter the Consumption of Ethanol and Sweet Fluids in Mice.

The central nucleus of the amygdala plays a significant role in alcohol use and other affective disorders; however, the genetically-defined neuronal subtypes and projections that govern these behaviors are not well known. Here we show that neurotensin neurons in the central nucleus of the amygdala of male mice are activated by ethanol consumption and that genetic ablation of these neurons decreases ethanol consumption and preference in non-ethanol-dependent animals. This ablation did not impact preference for sucrose, saccharin, or quinine.

Divergent behavioral responses in protracted opioid withdrawal in male and female C57BL/6J mice.

Persons suffering from opioid use disorder (OUD) experience long-lasting dysphoric symptoms well into extended periods of withdrawal. This protracted withdrawal syndrome is notably characterized by heightened anxiety and hyperkatifeia. Here, we investigated if an exacerbated withdrawal model of acute morphine dependence results in lasting behavioral adaptation 6 weeks into forced abstinence in C57BL/6J mice.

Chronic intermittent ethanol exposure dysregulates a GABAergic microcircuit in the bed nucleus of the stria terminalis.

Neuroadaptations in brain regions that regulate emotional and reward-seeking behaviors have been suggested to contribute to pathological behaviors associated with alcohol-use disorder. One such region is the bed nucleus of the stria terminalis (BNST), which has been linked to both alcohol consumption and alcohol withdrawal-induced anxiety and depression. Recently, we identified a GABAergic microcircuit in the BNST that regulates anxiety-like behavior.