Oxytocin signaling in the treatment of drug addiction: Therapeutic opportunities and challenges

Oxytocin decreases alcohol self-administration in male baboons

The neurohormone oxytocin (OT) has been proposed as a treatment for alcohol and nicotine use disorders. The aim of the present study was to examine whether intravenous (IV) OT decreases alcohol oral self-administration and consumption in nonhuman primates under a 6-h alcohol access procedure as well as alcohol and nicotine (IV) self-administration under 6-h concurrent access conditions. The subjects were five male baboons (Papio anubis) that self-administered oral alcohol (4% w/v) during 6-h sessions under a fixed ratio 3 (FR3) schedule per drink. Baseline levels of alcohol self-administration were established and then OT treatment was initiated. A single dose of OT (20, 40, 80, 120 IU, IV) or its vehicle (saline) was administered before and again in the middle of the 6-h drinking session for 5 consecutive days (total oxytocin dose of 40, 80, 160, 240 IU/day). After each 5-day treatment, baseline levels of alcohol self-administration were reestablished before the next 5-day OT treatment. In addition, the effect of OT on concurrent alcohol and IV nicotine self-administration was explored in 3 of the baboons where alcohol and nicotine were concurrently available during the 6-hr session each under an FR3 schedule for each drug. Establishment of baseline self-administration and 5-day OT treatments were completed as in the alcohol only study. There was a significant overall reduction in alcohol consumption with OT compared to placebo. On post-hoc analysis, after correcting for multiple comparisons, the 40 and 80 IU doses of OT significantly reduced alcohol consumption compared with vehicle, and consumption did not vary significantly within each 5-day treatment period. OT, qualitatively, also reduced the coadministration of both alcohol and nicotine in each baboon for at least one of the OT doses administered. These results underscore the therapeutic potential of oxytocin as a treatment of alcohol use disorder and possibly, co-use of nicotine.

Analysis of physical activity and prescription opioid use among US adults: a cross-sectional study

BACKGROUND

Opioid crisis has become a global concern, but whether physical activity (PA) can effectively reduce prescription opioid use remains unclear. The study aimed to examine the relationship of different domains of PA (e.g., occupation-related PA [OPA], transportation-related PA [TPA], leisure-time PA [LTPA]) with prescription opioid use and duration of prescription opioid use.

METHODS

This cross-sectional study was conducted on 27,943 participants aged ≥ 18 years from National Health and Nutrition Examination Survey (NHANES, 2007- March 2020). We examined the relationship of different domains of PA with prescription opioid use and duration of prescription opioid use using multivariable logistic regression. Stratified analysis and a series of sensitivity analysis were used to elevate robustness. All analyses were conducted using appropriate sampling weights.

RESULTS

Of the 27,943 participants, the mean age was 45.10 years, with 14,018 [weighted, 50.0%] females and 11,045 [weighted, 66.0%] non-Hispanic White. After multivariable adjustment, inverse associations between PA and prescription opioid use were observed for sufficient (≥ 150 min/week) total PA (OR,0.68 95%CI [0.56-0.81]), TPA (OR,0.73 95%CI [0.58-0.92]), and LTPA (OR,0.60 95%CI [0.48-0.75]) compared with insufficient PA(< 150 min/week), but not for sufficient OPA (OR,0.93 95%CI [0.79-1.10]). In addition, the associations were dose-responsive, participants had 22-40%, 27-36%, and 26-47% lower odds of using prescription opioids depending on the duration of total PA, TPA, and LTPA, respectively. Nevertheless, the impact of PA on prescription opioid use varied by duration of opioid use. Sufficient total PA was associated with elevated odds of short-term use of prescription opioids (< 90 days). Comparatively, sufficient total PA, TPA, and LTPA had different beneficial effects on reducing long-term use of prescription opioids (≥ 90 days) depending on the strength of opioids.

CONCLUSIONS

This study demonstrated sufficient total PA, TPA, and LTPA were inversely associated with prescription opioid use and varied depending on the duration and strength of prescription opioid use. These findings highlight PA can provide policy guidance to address opioid crisis.

Neuroprotective effects of oxytocin against ischemic stroke in rats by blocking glutamate release and CREB-mediated DNA hypermethylation

Glutamate plays a crucial role in cognitive impairments after ischemic stroke. There is a scarcity of information about how glutamate-induced activation of cAMP-response element binding (CREB) signaling pathway regulates both the negative and positive regulators of synaptic plasticity. Recent studies have demonstrated the involvement of prominent epigenetic repressors, such as MeCP2 and DNMTs, in stroke. Neuroprotective effects of oxytocin against ischemia have been previously reported, while the underlying mechanism is still elusive. In this research, the possible role of CREB-mediated DNA hypermethylation and the potential mechanism of oxytocin in a rat model of permanent middle cerebral artery occlusion (pMCAO) were assessed. Adult male Sprague-Dawley rats were pretreated with intraperitoneal injection of oxytocin at the onset of pMCAO. The effects of oxytocin on spines and the expression levels of synaptic genes were determined. The regulatory effects of oxytocin on glutamate level, N-methyl-D-aspartate receptors (NMDARs), its downstream CREB pathway, and global or gene-specific DNA methylation status were evaluated by immunofluorescence, co-immunoprecipitation, and chromatin immunoprecipitation, respectively. We found that CREB could act as a common transcription factor for MeCP2 and DNMT3B after ischemic stroke. Oxytocin dose-dependently deactivated NR2B-related CaM-CREB pathway and inhibited DNA hypermethylation at the CpG islands of Ngf gene in pMCAO-operated rats. Moreover, oxytocin prevented pMCAO-induced reduction in the number of spines and neural cells. DNA hypermethylation in Ngf gene contributed to the cognitive deficits post-stroke. The neuroprotective effects of oxytocin against ischemia could be attributed to inhibiting glutamate release, providing additional evidence on the mechanism of oxytocin against ischemic stroke.

Cocaine use disorder effects on blood oxytocin levels and OXTR DNA methylation

Substance use disorders have been associated with alterations in the oxytocinergic system, but few studies have investigated both the peptide and epigenetic mechanisms potentially implicated in the regulation of oxytocin receptor. In this study, we compared plasma oxytocin and blood DNA methylation in the OXTR gene between people with and without cocaine use disorder (CUD). We measured the oxytocin levels of 51 people with CUD during acute abstinence and of 30 healthy controls using an enzyme immunoassay. The levels of DNA methylation in four CpG sites at exon III of the OXTR gene were evaluated in a subsample using pyrosequencing. The Addiction Severity Index was used to assess clinical characteristics. We found higher oxytocin levels in men with CUD (56.5 pg/mL; 95% CI: 48.2-64.7) than in control men (33.6 pg/mL; 95% CI: 20.7-46.5), while no differences between women with and without CUD were detected. With a moderate effect size, the interaction effect between group and sex remained significant when controlling for height, weight and age data. A positive correlation in the CUD sample was found between oxytocin levels and days of psychological suffering prior to treatment enrollment. No group differences were observed regarding DNA methylation data. This suggests that CUD is associated with higher peripheral oxytocin levels in men during acute abstinence. This finding may be considered in future studies that aim at using exogenous oxytocin as a potential treatment for cocaine addiction.

Oxytocin as neuro-hormone and neuro-regulator exert neuroprotective properties: A mechanistic graphical review

BACKGROUND

Neurodegeneration is progressive cell loss in specific neuronal populations, often resulting in clinical consequences with significant medical, societal, and economic implications. Because of its antioxidant, anti-inflammatory, and anti-apoptotic properties, oxytocin has been proposed as a potential neuroprotective and neurobehavioral therapeutic agent, including modulating mood disturbances and cognitive enchantment.

METHODS

Literature searches were conducted using the following databases Web of Science, PubMed, Elsevier Science Direct, Google Scholar, the Core Collection, and Cochrane from January 2000 to February 2023 for articles dealing with oxytocin neuroprotective properties in preventing or treating neurodegenerative disorders and diseases with a focus on oxidative stress, inflammation, and apoptosis/cell death.

RESULTS

The neuroprotective effects of oxytocin appears to be mediated by its anti-inflammatory properties, inhibition of neuro inflammation, activation of several antioxidant enzymes, inhibition of oxidative stress and free radical formation, activation of free radical scavengers, prevent of mitochondrial dysfunction, and inhibition of apoptosis.

CONCLUSION

Oxytocin acts as a neuroprotective agent by preventing neuro-apoptosis, neuro-inflammation, and neuronal oxidative stress, and by restoring mitochondrial function.

Male-selective effects of oxytocin agonism on alcohol intake: behavioral assessment in socially housed prairie voles and involvement of RAGE

Targeting the oxytocin (OXT) peptide system has emerged as a promising new approach for the treatment of alcohol use disorder (AUD). However, further advancements in this development depend on properly modeling various complex social aspects of AUD and its treatment. Here we examined behavioral and molecular underpinnings of OXT receptor (OXTR) agonism in prairie voles, a rodent species with demonstrated translational validity for neurobiological mechanisms regulating social affiliations. To further improve translational validity of these studies, we examined effects of intranasal (IN) OXT administration in male and female prairie voles socially housed in the presence of untreated cagemates. IN OXT selectively inhibited alcohol drinking in male, but not female, animals. Further, we confirmed that exogenously administered OXT penetrates the prairie vole brain and showed that Receptor for Advanced Glycation End-products assists this penetration after IN, but not intraperitoneal (IP), OXT administration. Finally, we demonstrated that IP administration of LIT-001, a small-molecule OXTR agonist, inhibits alcohol intake in male, but not female, prairie voles socially housed in the presence of untreated cagemates. Taken together, results of this study support the promise of selectively targeting OXTR for individualized treatment of AUD.

Effect of light needle in the treatment of opioid use disorder: A protocol for a randomized controlled trial

BACKGROUND

Opioid use disorder occurs worldwide and creates an increasing economic burden and public health crisis. Some problems are associated with using opioid agonists; therefore, there is a need to develop non-opioid treatments to improve acute and long-term opioid withdrawal syndromes.

METHODS

We will enroll 100 participants with opioid use disorders receiving methadone maintenance treatment at an addiction treatment center and randomly allocate them to an experimental or control group. The experimental group will receive 12 sessions of light needle therapy within 4 weeks, while the control group will receive sham light needle treatment without any laser output. Urinary morphine levels were assessed before and after treatment. Participants will be asked to self-report their number of episodes or days of heroin use and heroin craving/refusal to use heroin in the previous week before and after treatment on a visual analogue scale score of 0 to 10. Quality of life will be reported using the Short Form-12v2 before and after 4 weeks of treatment. Pulse diagnosis and heart rate variability will be evaluated before and after treatment. Baseline patient characteristics will be compared between the groups using the independent t test and the χ2 test. Data between the 2 groups will be compared using generalized estimation equations, and paired t tests.

OBJECTIVE

This study aims to investigate the effect of adjuvant light needle therapy in patients with opioid use disorder on methadone maintenance treatment.

Oxytocin moderates corticolimbic social stress reactivity in cocaine use disorder and healthy controls

Social stress can contribute to the development of substance use disorders (SUDs) and increase the likelihood of relapse. Oxytocin (OT) is a potential pharmacotherapy that may buffer the effects of social stress on arousal and reward neurocircuitry. However, more research is needed to understand how OT moderates the brain’s response to social stress in SUDs. The present study examined the effect of intransasal OT (24 IU) versus placebo (PBO) on corticolimbic functional connectivity associated with acute social stress in individuals with cocaine use disorder (CUD; n = 67) and healthy controls (HC; n = 52). Psychophysiological interaction modeling used the left and right amygdala as seed regions with the left and right orbitofrontal and anterior cingulate cortex as a priori regions of interest. Moderators of the OT response included childhood trauma history and biological sex, which were examined in independent analyses. The main finding was that OT normalized corticolimbic connectivity (left amygdala-orbitofrontal and left amygdala-anterior cingulate) as a function of childhood trauma such that connectivity was different between trauma-present and trauma-absent groups on PBO, but not between trauma groups on OT. Effects of OT on corticolimbic connectivity were not different as a function of diagnosis (CUD vs HC) or sex. However, OT reduced subjective anxiety during social stress for CUD participants who reported childhood trauma compared to PBO and normalized craving response as a function of sex in CUD. The present findings add to some prior findings of normalizing effects of OT on corticolimbic circuitry in individuals with trauma histories and provide some initial support that OT can normalize subjective anxiety and craving in CUD.

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Social stress-related corticolimbic connectivity was affected by childhood trauma under placebo.

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Under oxytocin, corticolimbic connectivity differences due to childhood trauma were absent.

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Oxytocin reduced subjective anxiety in cocaine users with childhood trauma.

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Oxytocin reduced subjective craving in male cocaine users.

Oxytocin and cardiometabolic interoception: Knowing oneself affects ingestive and social behaviors

Maintaining homeostasis while navigating one's environment involves accurately assessing and interacting with external stimuli while remaining consciously in tune with internal signals such as hunger and thirst. Both atypical social interactions and unhealthy eating patterns emerge as a result of dysregulation in factors that mediate the prioritization and attention to salient stimuli. Oxytocin is an evolutionarily conserved peptide that regulates attention to exteroceptive and interoceptive stimuli in a social environment by functioning in the brain as a modulatory neuropeptide to control social behavior, but also in the periphery as a hormone acting at oxytocin receptors (Oxtr) expressed in the heart, gut, and peripheral ganglia. Specialized sensory afferent nerve endings of Oxtr-expressing nodose ganglia cells transmit cardiometabolic signals via the Vagus nerve to integrative regions in the brain that also express Oxtr(s). These brain regions are influenced by vagal sensory pathways and coordinate with external events such as those demanding attention to social stimuli, thus the sensations related to cardiometabolic function and social interactions are influenced by oxytocin signaling. This review investigates the literature supporting the idea that oxytocin mediates the interoception of cardiovascular and gastrointestinal systems, and that the modulation of this awareness likewise influences social cognition. These concepts are then considered in relation to Autism Spectrum Disorder, exploring how atypical social behavior is comorbid with cardiometabolic dysfunction.

Oxytocin: An Old Hormone, A Novel Psychotropic Drug And Possible Use In Treating Psychiatric Disorders

BACKGROUND

Oxytocin is a nonapeptide synthesized in the paraventricular and supraoptic nuclei of the hypothalamus. Historically, this molecule has been involved as a key factor in the formation of infant attachment, maternal behavior and pair bonding and, more generally, in linking social signals with cognition, behaviors and reward. In the last decades, the whole oxytocin system has gained a growing interest as it was proposed to be implicated in etiopathogenesis of several neurodevelopmental and neuropsychiatric disorders.

METHODS

With the main goal of an in-depth understanding of the oxytocin role in the regulation of different functions and complex behaviors as well as its intriguing implications in different neuropsychiatric disorders, we performed a critical review of the current state of art. We carried out this work through PubMed database up to June 2021 with the search terms: 1) "oxytocin and neuropsychiatric disorders"; 2) "oxytocin and neurodevelopmental disorders"; 3) "oxytocin and anorexia"; 4) "oxytocin and eating disorders"; 5) "oxytocin and obsessive-compulsive disorder"; 6) "oxytocin and schizophrenia"; 7) "oxytocin and depression"; 8) "oxytocin and bipolar disorder"; 9) "oxytocin and psychosis"; 10) "oxytocin and anxiety"; 11) "oxytocin and personality disorder"; 12) "oxytocin and PTSD".

RESULTS

Biological, genetic, and epigenetic studies highlighted quality and quantity modifications in the expression of oxytocin peptide or in oxytocin receptor isoforms. These alterations would seem to be correlated with a higher risk of presenting several neuropsychiatric disorders belonging to different psychopathological spectra. Collaterally, the exogenous oxytocin administration has shown to ameliorate many neuropsychiatric clinical conditions.

CONCLUSION

Finally, we briefly analyzed the potential pharmacological use of oxytocin in patient with severe symptomatic SARS-CoV-2 infection due to its anti-inflammatory, anti-oxidative and immunoregulatory properties.

Barriers and Breakthroughs in Targeting the Oxytocin System to Treat Alcohol Use Disorder

Development of better treatments for alcohol use disorder (AUD) is urgently needed. One promising opportunity for this development is the potential of targeting the oxytocin peptide system. Preclinical studies showed that administration of exogenous oxytocin or, more recently, stimulation of neurons expressing endogenous oxytocin lead to a decreased alcohol consumption across several rodent models. Initial clinical studies also showed that administration of oxytocin decreased craving for alcohol and heavy alcohol drinking. However, several more recent clinical studies were not able to replicate these effects. Thus, although targeting the oxytocin system holds promise for the treatment of AUD, more nuanced approaches toward development and application of these treatments are needed. In this mini-review we discuss potential caveats resulting in differential success of attempts to use oxytocin for modulating alcohol use disorder-related behaviors in clinical studies and evaluate three directions in which targeting the oxytocin system could be improved: (1) increasing potency of exogenously administered oxytocin, (2) developing oxytocin receptor agonists, and (3) stimulating components of the endogenous oxytocin system. Both advances and potential pitfalls of these directions are discussed.

Oxytocin, a Novel Treatment for Methamphetamine Use Disorder

The treatment of substance abuse with oxytocin is a novel approach to a challenging public health issue that continues to contribute to a growing economic cost for societies worldwide. Methamphetamine addiction is one of the leading causes of mortality worldwide, and despite advances in understanding the neurobiology of methamphetamine addiction, treatment options are limited. There are no medications that the Food and Drug Administration currently approves for stimulant use disorder. Off-label use of therapies for stimulant misuse include antidepressants, anxiolytics, and milder stimulants as replacement agents. Due to the shortcomings of these attempts to treat a complicated psychiatric disorder, recent attention to oxytocin therapy (OT) has gained momentum in clinical studies as a possible therapy in the context of social stress, social anxiety, social cognition, and psychosis. Oxytocin produces enhanced connectivity between cortical regions. The results from studies in rodents with OT suggest that central neuromodulation of oxytocin may be beneficial across transition states of stimulant dependence and may alleviate intense withdrawal symptoms. Studies of oxytocin in the context of other drugs of abuse, including cocaine, cannabis, and alcohol, also support the potential of oxytocin to treat stimulant use disorder, methamphetamine type. Methamphetamine abuse continues to be a significant cause of distress and dysfunction throughout the world. The effects of oxytocin on methamphetamine use outlined in this review should act as a catalyst for further investigation into the efficacy of treating stimulant use disorder, methamphetamine type with oxytocin in humans. More human-based research should initiate studies involving the long-term efficacy, side effects, and patient selection.

Repeated oxytocin treatment during abstinence inhibited context- or restraint stress-induced reinstatement of methamphetamine-conditioned place preference and promoted adult hippocampal neurogenesis in mice

Propensity to relapse, even after long-term abstinence, is a crucial feature of methamphetamine (METH) abuse. We and other laboratories have reported that acute treatment of oxytocin (OXT), a hormone and neuropeptide, could inhibit reinstatement of METH seeking in animal studies. However, the effects of repeated OXT treatment on METH reinstatement as well as underlying mechanisms are still unclear. In the present study, the effects of repeated OXT treatment during abstinence on context- or restraint stress-induced reinstatement were investigated using the mice conditioned place preference (CPP) paradigm. After three intermittent injections of METH (2 mg/kg, i.p.) to induce CPP, mice received a daily bilateral intra-hippocampus injection of OXT (0.625, 1.25 or 2.5 μg) for 8 consecutive days before the context- or restraint stress-induced reinstatement test. Meanwhile, adult hippocampal neurogenesis (AHN) level was detected using immunostaining. To further clarify the role of AHN underlying OXT's effects on METH-CPP reinstatement, temozolomide (TMZ, 25 mg/kg, i.p.) was employed to deplete AHN prior to OXT treatment. The data showed that repeated OXT treatment (1.25 and 2.5 μg, intra-hippocampus) significantly inhibited both context- and restraint stress-induced METH-CPP reinstatement and concomitantly promoted AHN in a dose-dependent manner. Notably, TMZ pre-treatment markedly abolished all the above-mentioned effects of OXT, suggesting that AHN was closely involved in OXT's inhibition on reinstatement induced by both triggers. Taken together, the present study indicated that repeated OXT treatment during abstinence could inhibit both context- and restraint stress-induced METH-CPP reinstatement possibly by promoting AHN in mice, which provided a better understanding for OXT's beneficial effects on METH addiction.