History of the development of antifungal azoles: A review on structures, SAR, and mechanism of action.

With the increasing risk of invasive and life threating fungal infections, there is now a great concern regarding the lower discovery rate of antifungal drugs in comparison to antimicrobial agents. Drugs conventionally used in clinics are not adequate enough to combat the increasing fungal infections, especially fungal forms resistant to fluconazole. Among the limited antifungal agents in clinics, azoles have the largest number of drug candidates in clinical trials and are partly marketed due to the particular focus of pharmaceutical companies and medicinal scientific centers. With the rise in the number of papers on azole antifungal design and discovery, a more in-depth understanding the most recent and authentic information about this class of drugs might be beneficial. To this end, we for the first time summarized the state-of-the-art information about azole drugs, with a specific focus on those in the pipelines of pharmaceutical companies, into four generations with regard to their structural similarity. More importantly, this review highlights information on the structure activity relationship (SAR), target description, hybrid antifungal agents as possible future generation, and other useful issues to streamline research towards designing new efficient azole antifungal structures in future.

Ethanol induces maladaptive impulse control and decreased seeking behaviors in mice.

Waiting impulsivity is a risk factor for many psychiatric disorders including alcohol use disorder (AUD). Highly impulsive individuals are vulnerable to alcohol abuse. However, it is not well understood whether chronic alcohol use increases the propensity for impulsive behavior. Here, we establish a novel experimental paradigm demonstrating that continuous binge-like ethanol exposure progressively leads to maladaptive impulsive behavior. To test waiting impulsivity, we employed the 5-choice serial reaction time task (5-CSRTT) in C57BL/6J male mice. We assessed premature responses in the fixed and variable intertrial interval (ITI) 5-CSRTT sessions. We further characterized our ethanol-induced impulsive mice using Open Field, y-maze, two-bottle choice, and an action-outcome task. Our results indicate that continuous binge-like ethanol exposure significantly increased premature responses when mice were tested in variable ITI sessions even during a prolonged abstinent period. Ethanol-induced impulsive mice exhibited anxiety-like behavior during chronic exposures. This behavior was also observed in a separate cohort that was subjected to 20 days of abstinence. Ethanol-treated mice were less motivated for a sucrose reward compared with air-exposed control mice, while also demonstrating reduced responding during action-outcome testing. Overall, ethanol-treated mice demonstrated increased impulsive behavior, but a reduced motivation for a sucrose reward. Although waiting impulsivity has been hypothesized to be a trait or risk factor for AUD, our findings indicate that maladaptive impulse control can also be potentiated or induced by continuous chronic ethanol exposure in mice.

Type 1 equilibrative nucleoside transporter (ENT1) regulates sex-specific ethanol drinking during disruption of circadian rhythms.

Disruptions in circadian rhythms are risk factors for excessive alcohol drinking. The ethanol-sensitive adenosine equilibrative nucleoside transporter type 1 (ENT1, slc29a1) regulates ethanol-related behaviors, sleep, and entrainment of circadian rhythms. However, the mechanism underlying the increased ethanol consumption in ENT1 knockout (KO) mice in constant light (LL) and whether there are sex differences in ethanol consumption in ENT1 mice are less studied. Here, we investigated the effects of loss of ENT1, LL, and sex on ethanol drinking using two-bottle choice. In addition, we monitored the locomotor activity rhythms. We found that LL increased ethanol drinking and reduced accumbal ENT1 expression and adenosine levels in male but not female mice, compared with control mice. Interestingly, only LL-exposed male, not female, ENT1 KO mice exhibited higher ethanol drinking and a longer circadian period with a higher amplitude compared with wild-type (WT) mice. Furthermore, viral-mediated rescue of ENT1 expression in the NAc of ENT1 KO mice reduced ethanol drinking, demonstrating a possible causal link between ENT1 expression and ethanol drinking in males. Together, our findings indicate that deficiency of ENT1 expression contributes to excessive ethanol drinking in a sex-dependent manner.

Proteomic Profile of a Chronic Binge Ethanol Exposure Model.

Chronic binge alcohol drinking is known to increase risky decision through pathological impulsive behaviors. Recently, we established a novel rodent model of ethanol-induced waiting impulsivity using 5-choice serial reaction time task (5-CSRTT) in mice. However, molecular mechanisms underlying the chronic binge ethanol-induced waiting impulsivity is not well characterized. Among brain regions involved in impulsivity, the anterior cingulate cortex (ACC) is a major neural substrate for mediating the 5-CSRTT-based waiting impulsivity. Thus, we sought to determine the ACC proteomic profile using label-free proteomics of mice exhibiting ethanol-induced impulsivity. Ingenuity pathway analysis revealed that impulsivity-related proteins involved in ion channel complexes such as KCNIP3 (potassium voltage-gated channel interacting protein 3) and CACNG2 (calcium voltage-gated channel auxiliary subunit gamma 2) are downregulated in the ACC. We identified significant protein expression changes in the mechanistic target of rapamycin (mTOR) canonical pathway between control and ethanol-induced impulsive mice. Impulsive mice showed over 60% of proteins involved in the mTOR canonical pathway have been altered. This pathway has been previously implicated in the neuroadaptation in drugs of abuse and impulsivity. We found substantial changes in the protein levels involved in neurological disorders such as schizophrenia and Alzheimer's disease. Our findings provide a neuroproteomic profile of ethanol-induced impulsive mice.

Novel Adenosine Analog, N6-(4-Hydroxybenzyl)-Adenosine, Dampens Alcohol Drinking and Seeking Behaviors.

Adenosine signaling is associated with ethanol-related behaviors. We previously found that adenosine A2A receptor (A2AR) activation dampens ethanol drinking behaviors in equilibrative nucleoside transporter 1 (ENT1) knockout mice, and A2AR inhibition augments reward-seeking behavior in wild-type mice. The novel adenosine analog N6-(4-hydroxybenzyl)-adenosine (NHBA), which is isolated from the rhizomes of Gastrodia elata, activates A2AR and inhibits ENT1. Here, we examined the effects of NHBA on ethanol drinking in the two-bottle choice test and operant ethanol seeking behaviors. We selected mice exhibiting high ethanol drinking behavior in the two-bottle choice test. NHBA (0.1 mg/kg, i.p.) reduced ethanol drinking behavior in a limited-access 3-hour drinking session in high-consumption ethanol drinking mice, and NHBA (0.1 mg/kg, i.p.) did not alter locomotor activity in the open-field test. Operant conditioning with 10% ethanol and 10% sucrose (10E10S) reward increased zone entries and time spent in the ethanol zone, while NHBA (0.1 mg/kg, i.p.) dampened ethanol zone preference in the Y-maze. Furthermore, NHBA (0.1 mg/kg, i.p.) devalued 10E10S and 10% ethanol (10E) reward after operant conditioning with 10E10S and 10E. Taken together, NHBA through A2AR activation and ENT1 modulation may dampen ethanol drinking and seeking behaviors, suggesting that NHBA is a potential therapeutic agent for treating alcohol use disorder. SIGNIFICANCE STATEMENT: Our work highlights that A2AR activation and ENT1 inhibition by a novel adenosine analog isolated from Gastrodia elata, N6-(4-hydroxybenzyl)-adenosine, decreases ethanol drinking and seeking behaviors. We suggest that NHBA is a potential therapeutic agent to treat alcohol use disorder.

Chronic Ethanol Exposure Disrupts Lactate and Glucose Homeostasis and Induces Dysfunction of the Astrocyte-Neuron Lactate Shuttle in the Brain.

BACKGROUND: Impairment of monocarboxylate transporter (MCT)-dependent astrocyte-neuron lactate transfer disrupts long-term memory and erases drug-associated memories in mice. However, few studies have examined how drugs of abuse alter astrocyte-neuron lactate transfer in neurocircuits related to addiction. This is particularly pertinent for ethanol (EtOH), which has been demonstrated to impair central nervious system (CNS) glucose uptake and significantly alter peripheral levels of glucose, lactate, acetate, and ketones. METHODS: We subjected C57BL/6J mice to a chronic intermittent EtOH (CIE) exposure paradigm to investigate how chronic EtOH exposure alters the concentration of glucose and lactate within the serum and CNS during withdrawal. Next, we determine how chronic injections of lactate (1 g/kg, twice daily for 2 weeks) influence central and peripheral glucose and lactate concentrations. Finally, we determine how CIE and chronic lactate injection affect astrocyte-neuron lactate transfer by analyzing the expression of MCTs. RESULTS: Our results show that CIE induces lasting changes in CNS glucose and lactate concentrations, accompanied by increased expression of MCTs. Interestingly, although chronic lactate injection mimics the effect of EtOH on CNS metabolites, chronic lactate injection is not associated with increased expression of MCTs. CONCLUSION: CIE increases CNS concentrations of glucose and lactate and augments the expression of MCTs. Although we found that chronic lactate injection mimics EtOH-induced increases in CNS lactate and glucose, lactate failed to alter the expression of MCTs. This suggests that although lactate may influence the homeostasis of bioenergetic molecules in the CNS, EtOH-associated increases in lactate are not responsible for increased MCT expression.

External globus pallidus input to the dorsal striatum regulates habitual seeking behavior in male mice.

The external globus pallidus (GPe) coordinates action-selection through GABAergic projections throughout the basal ganglia. GPe arkypallidal (arky) neurons project exclusively to the dorsal striatum, which regulates goal-directed and habitual seeking. However, the role of GPe arky neurons in reward-seeking remains unknown. Here, we identified that a majority of arky neurons target the dorsolateral striatum (DLS). Using fiber photometry, we found that arky activities were higher during random interval (RI; habit) compared to random ratio (RR; goal) operant conditioning. Support vector machine analysis demonstrated that arky neuron activities have sufficient information to distinguish between RR and RI behavior. Genetic ablation of this arkyGPe→DLS circuit facilitated a shift from goal-directed to habitual behavior. Conversely, chemogenetic activation globally reduced seeking behaviors, which was blocked by systemic D1R agonism. Our findings reveal a role of this arkyGPe→DLS circuit in constraining habitual seeking in male mice, which is relevant to addictive behaviors and other compulsive disorders.

A novel monobactam lacking antimicrobial activity, MC-100093, reduces sex-specific ethanol preference and depressive-like behaviors in mice.

Several ß-lactam derivatives upregulate astrocytic glutamate transporter type 1expression and are known to improve measures in models of mood and alcohol use disorders (AUD) through normalizing glutamatergic states. However, long-term, and high doses of ß-lactams may cause adverse side effects for treating mood disorders and AUD. Studies suggest that MC-100093, a novel ß-lactam lacking antimicrobial activity, rescues GLT1 expression. Thus, we sought to investigate whether MC-100093 improves affective behaviors and reduces voluntary ethanol drinking. We intraperitoneally administered MC-100093 (50 mg/kg) or vehicle once per day to C57BL/6J male and female mice (8-10 weeks old) over 6 days. We employed the open field test and the elevated plus maze to examine the effect of MC-100093 on anxiety-like behaviors. We assayed MC-100093's effects on depressive-like behaviors using the tail suspension and forced swim tests. Next, utilizing a separate cohort of male and female C57BL6 mice, we assessed the effects MC100093 treatment on voluntary ethanol drinking utilizing the 2-bottle choice continuous access drinking paradigm. After screening and selecting high-drinking mice, we systematically administered MC-100093 (50 mg/kg) or vehicle to the high-drinking mice over 6 days. Overall, we found that MC-100093 treatment resulted in sex-specific pharmacological effects with female mice displaying reduced innate depressive-like behaviors during the tail suspension and force swim testing juxtaposed with male treated mice who displayed no changes in tail suspension and a paradoxical increased depressive-like behavior during the forced swim testing. Additionally, we found that MC100093 treatment reduced female preference for 10% EtOH during the 2-bottle choice continuous access drinking with no effects of MC100093 treatment detected in male mice. Overall, this data suggests sex-specific regulation of innate depressive-like behavior and voluntary EtOH drinking by MC100093 treatment. Western blot analysis of the medial prefrontal cortex and hippocampus revealed no changes in male or female GLT1 protein abundance relative to GAPDH.

A comprehensive review of the ten main platelet receptors involved in platelet activity and cardiovascular disease.

Cardiovascular disease (CVD) is a major cause of death worldwide. Although there are many variables that contribute to the development of this disease, it is predominantly the activity of platelets that provides the mechanisms by which this disease prevails. While there are numerous platelet receptors expressed on the surface of platelets, it is largely the consensus that there are 10 main platelet receptors that contribute to a majority of platelet function. Understanding these key platelet receptors is vitally important for patients suffering from myocardial infarction, CVD, and many other diseases that arise due to overactivation or mutations of these receptors. The goal of this manuscript is to review the main platelet receptors that contribute most to platelet activity.

Adenosine receptors: Emerging non-opioids targets for pain medications.

Physical and emotional pain deteriorates the quality of well-being. Also, numerous non-invasive and invasive treatments for diagnosed diseases such as cancer medications and surgical procedures cause various types of pain. Despite the multidisciplinary approaches available to manage pain, the unmet needs for medication with minimal side effects are substantial. Especially with the surge of opioid crisis during the last decades, non-opioid analgesics may reduce life-threatening overdosing and addictive liability. Although many clinical trials supported the potential potency of cannabis and cannabidiol (CBD) in pain management or treatment, the long-term benefits of cannabis or CBD are still not evident. At the same time, growing evidence shows the risk of overusing cannabis and CBD. Therefore, it is urgent to develop novel analgesic medications that minimize side effects. All four well-identified adenosine receptors, A1, A2A, A2B, and A3, are implicated in pain. Recently, a report demonstrated that an adenosine A1R-specific positive allosteric modulator (PAM) is a potent analgesic without noticeable side effects. Also, several A3R agonists are being considered as promising analgesic agent. However, the importance of adenosine in pain is relatively underestimated. To help readers understand, first, we will summarize the historical perspective of the adenosine system in preclinical and clinical studies. Then, we will discuss possible interactions of adenosine and opioids or the cannabis system focusing on pain. Overall, this review will provide the potential role of adenosine and adenosine receptors in pain treatment.

The effects of estrogen and hormone replacement therapy on platelet activity: a review.

Many studies have shown that an increase in cardiovascular disease in women is related to hormonal changes occurring particularly after menopause with increasing age. While the results of large clinical trials reporting no benefit of hormone replacement therapy (HRT) in cardiovascular disease have been known for some time, there is an increasing body of knowledge regarding the various mechanisms by which estrogen modulates platelet function that could in part explain the higher cardiovascular risk occurring in postmenopausal women and potential benefits of HRT on cardiovascular health. Our review summarizes our current knowledge regarding the effect of endogenous and exogenous estrogen on platelet activity, which can help researchers design future studies. We collected information from 21 peer-reviewed articles published from 1993 to 2021. Studies have indicated that postmenopausal women have higher platelet activity than premenopausal women, which can increase the risk of thrombo-embolic events and cardiovascular disease. Although some studies have reported pro-thrombotic effects of estrogen replacement therapy such as increased platelet activation and adhesion, other studies demonstrated decreased platelet aggregation by inhibiting GP IIb/IIIa receptor expression. This is mediated by estrogen receptors on the platelet membrane in a non-genomic manner and suggests an opportunity for the usage of estrogen replacement therapy with subtle changes in the formulation and route, particularly if started early after menopause. The effect of estrogen on platelet activity is promising as an important factor in reducing the risk of cardiovascular events, warranting further investigation.

N6-substituated adenosine analog J4 attenuates anxiety-like behaviors in mice.

RATIONALE: Withdrawal from chronic alcohol exposure produces various physical and mental withdrawal symptoms. Activation of adenosine receptors is known to inhibit withdrawal-induced excitation. However, limited studies investigate how adenosine analogs may prove helpful tools to alleviate alcohol withdrawal-related affective behaviors. OBJECTIVES: This study aimed to investigate the effects of J4 compared with saline using the mice vapor or voluntary ethanol drinking model on behavioral endpoints representing ethanol-withdrawal negative emotionality commonly observed during abstinence from chronic alcohol use. METHODS: We subjected C57BL/6 J mice to chronic intermittent ethanol (CIE) exposure schedule to investigate how 72-h withdrawal from alcohol alters affective-like behavior. Next, we determined how treatment with J4, a second-generation adenosine analog, influenced affective behaviors produced by alcohol withdrawal. Finally, we determined how J4 treatment alters voluntary ethanol drinking using the two-bottle-choice drinking paradigm. RESULTS: Our results show that 72-h withdrawal from chronic intermittent ethanol exposure produces limited affective-like disturbances in male C57BL/6 J mice exposed to 4 cycles ethanol vapor. Most importantly, J4 treatment irrespective of ethanol exposure decreases innate anxiety-like behavior in mice. CONCLUSIONS: Withdrawal from chronic intermittent ethanol exposure and subsequent behavioral testing 72 h later produces minimal affective-like behavior. J4 treatment did however reduce marble-burying behavior and increased time spent in open arms of the elevated plus maze, suggesting J4 may be useful as a general anxiolytic.

Implication of Adult Hippocampal Neurogenesis in Alzheimer's Disease and Potential Therapeutic Approaches.

Alzheimer's disease is the most common neurodegenerative disease, affecting more than 6 million US citizens and representing the most prevalent cause for dementia. Neurogenesis has been repeatedly reported to be impaired in AD mouse models, but the reason for this impairment remains unclear. Several key factors play a crucial role in AD including Aß accumulation, intracellular neurofibrillary tangles accumulation, and neuronal loss (specifically in the dentate gyrus of the hippocampus). Neurofibrillary tangles have been long associated with the neuronal loss in the dentate gyrus. Of note, Aß accumulation plays an important role in the impairment of neurogenesis, but recent studies started to shed a light on the role of APP gene expression on the neurogenesis process. In this review, we will discuss the recent approaches to neurogenesis in Alzheimer disease and update the development of therapeutic methods.

A Comprehensive Review of PCSK9 Inhibitors.

Cardiovascular disease (CVD) is the leading cause of death in the United States and worldwide. A major risk factor for this condition is increased serum low-density lipoprotein cholesterol (LDL-C) levels for which statins have been successful in reducing serum LDL-C to healthy concentrations. However, patients who are statin intolerant or those who do not achieve their treatment goals while on high-intensity statin therapy, such as those with familial hypercholesterolemia, remain at risk. With the discovery of PCSK9 inhibitors, the ability to provide more aggressive treatment for patients with homozygous and heterozygous familial hypercholesterolemia has increased. Ezetimibe reduces LDL-C by 15%-20% when combined with statin.2,3 Protein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have been found to achieve profound reductions in LDL-C (54%-74%) when added to statins. They have shown dramatic effects at lowering major adverse cardiovascular events (MACE) in high-risk patients4 with LDL-C levels ≥70 mg/dL and can be used in populations that are statin intolerant or not at goal levels with maximally tolerated statin therapy. PCSK9 inhibitors also produce minimal side effects. Myopathy, a common side effect for patients on statins, has been rare in patients on PCSK9 inhibitors. Randomized trials have shown that reduction in LDL-C has translated to clinical benefits even in patients who have not achieved their LDL-C target.

Hippocampal regenerative medicine: neurogenic implications for addiction and mental disorders.

Psychiatric illness is a prevalent and highly debilitating disorder, and more than 50% of the general population in both middle- and high-income countries experience at least one psychiatric disorder at some point in their lives. As we continue to learn how pervasive psychiatric episodes are in society, we must acknowledge that psychiatric disorders are not solely relegated to a small group of predisposed individuals but rather occur in significant portions of all societal groups. Several distinct brain regions have been implicated in neuropsychiatric disease. These brain regions include corticolimbic structures, which regulate executive function and decision making (e.g., the prefrontal cortex), as well as striatal subregions known to control motivated behavior under normal and stressful conditions. Importantly, the corticolimbic neural circuitry includes the hippocampus, a critical brain structure that sends projections to both the cortex and striatum to coordinate learning, memory, and mood. In this review, we will discuss past and recent discoveries of how neurobiological processes in the hippocampus and corticolimbic structures work in concert to control executive function, memory, and mood in the context of mental disorders.

Astrocytic glutamate transporter 1 (GLT1) deficient mice exhibit repetitive behaviors.

Glutamatergic dysregulation is known to contribute to obsessive-compulsive disorder (OCD). Astrocytic glutamate transporter 1 (GLT1) is responsible for the majority of glutamate clearance. However, the role of GLT1 in OCD-like behavior remains unclear. Here, we found that astrocytic GLT1 deficient mice showed increased wheel running activity but reduced home cage activity. Notably, they exhibited elevated grooming/rearing time and increased repetitive behavior counts in contextual and cued fear conditioning. In addition, they showed increased rearing counts in the metabolic chamber, and also augmented rearing time and jumping counts in the open field test. Taken together, our findings suggest that astrocytic GLT1 deficiency promotes OCD-like repetitive behaviors.

Design, Synthesis, and In Vitro and In Vivo Evaluation of Novel Fluconazole-Based Compounds with Promising Antifungal Activities.

Demand has arisen for developing new azole antifungal agents with the growth of the resistant rate of infective fungal species to current azole antifungals in recent years. Accordingly, the present study reports the synthesis of novel fluconazole (FLC) analogues bearing urea functionality that led to discovering new azole agents with promising antifungal activities. In particular, compounds 8b and 8c displayed broad-spectrum activity and superior in vitro antifungal capabilities compared to the standard drug FLC against sensitive and resistant Candida albicans (C. albicans). The highly active compounds 8b and 8c had potent antibiofilm properties against FLC-resistant C. albicans species. Additionally, these compounds exhibited very low toxicity for three mammalian cell lines and human red blood cells. Time-kill studies revealed that our synthesized compounds displayed a fungicidal mechanism toward fungal growth. Furthermore, a density functional theory (DFT) calculation, additional docking, and independent gradient model (IGM) studies were performed to analyze their structure-activity relationship (SAR) and to assess the molecular interactions in the related target protein. Finally, in vivo results represented a significant reduction in the tissue fungal burden and improvements in the survival rate in a mice model of systemic candidiasis along with in vitro and in silico studies, demonstrating the therapeutic efficiency of compounds 8b and 8c as novel leads for candidiasis drug discovery.

Chronic Alcohol Exposure Induces Aberrant Mitochondrial Morphology and Inhibits Respiratory Capacity in the Medial Prefrontal Cortex of Mice.

Alcohol use disorder (AUD) is characterized as a chronic, relapsing disease with a pattern of excessive drinking despite negative consequences to an individual's life. Severe chronic alcohol use impairs the function of the medial prefrontal cortex (mPFC), which contributes to alcohol-induced cognitive and executive dysfunction. The mPFC contains more mitochondria compared to other cortical areas, which suggests mitochondrial damage may occur in AUD and trigger subsequent behavior change. Here, we identified morphological and functional changes in mitochondria in the mPFC in C57BL6/J mice after 8 h of withdrawal from chronic intermittent alcohol (CIA) exposure. Three-dimensional serial block-face scanning electron microscopy (SBFSEM) reconstruction revealed that CIA exposure elongated mPFC mitochondria and formed mitochondria-on-a-string (MOAS). Furthermore, alcohol significantly affected mitochondrial bioenergetics, including oxidative phosphorylation and electron transport, with inhibited aerobic respiration in mPFC mitochondria after CIA exposure. We also found decreased expression of fusion (mitofusin 2, Mfn2) and increased fission (mitochondrial fission 1 protein, Fis1) proteins in the mPFC of alcohol-treated mice. In sum, our study suggests that CIA exposure impairs mitochondrial dynamics and function in the mPFC.

Astrocytic Glutamate Transporter 1 (GLT1) Deficiency Reduces Anxiety- and Depression-Like Behaviors in Mice.

Glutamatergic dysregulation is known to contribute to altered emotional regulation. Astrocytic glutamate transporter 1 (GLT1) is responsible for the majority of glutamate clearance from synapse. However, the role of astrocytic GLT1 in affective processes such as anxiety- and depression-like behavior is not fully understood. Here, we found that astrocytic GLT1 deficient mice entered more frequently, and spent more time in the open arms of elevated plus maze without difference in overall distance traveled in the open field, nor were there any metabolic changes observed in the metabolic chamber compared to wildtype mice. Moreover, mice lacking astrocytic GLT1 exhibited less immobile time and moved greater area in the tail suspension test. Similarly, in the forced swim test, they showed less immobile time and moved greater area. In addition, we found that astrocytic GLT1 deficiency reduced freezing responses in the fear contextual and cued tests. Taken together, our findings suggest that astrocytic GLT1 deficiency decreases anxiety and depression-like behaviors.

Activation of Astrocytes in the Dorsomedial Striatum Facilitates Transition From Habitual to Goal-Directed Reward-Seeking Behavior.

BACKGROUND: Habitual reward-seeking behavior is a hallmark of addictive behavior. The role of the dorsomedial striatum (DMS) in regulating goal-directed reward-seeking behavior has been long appreciated. However, it remains unclear how the astrocytic activities in the DMS differentially affect the behavioral shift. METHODS: To investigate the astrocytic activity-driven neuronal synaptic events and behavioral consequences, we chemogenetically activated astrocytes in the DMS using GFAP promoter-driven expression of hM3Dq, the excitatory DREADDs (designer receptors exclusively activated by designer drugs). First, we confirmed the chemogenetically induced cellular activity in the DMS astrocytes using calcium imaging. Then, we recorded electrophysiological changes in the synaptic activity of the two types of medium spiny neurons (MSNs): direct and indirect pathway MSNs. To evaluate the behavioral consequences, we trained mice in nose-poking operant chambers that developed either habitual or goal-directed reward-seeking behaviors. RESULTS: The activation of DMS astrocytes reduced the frequency of spontaneous excitatory postsynaptic currents in the direct pathway MSNs, whereas it increased the amplitude of the spontaneous excitatory postsynaptic currents and decreased the frequency of spontaneous inhibitory postsynaptic currents in the indirect pathway MSNs. Interestingly, astrocyte-induced DMS neuronal activities are regulated by adenosine metabolism, receptor signaling, and transport. Importantly, mice lacking an astrocytic adenosine transporter, ENT1 (equilibrative nucleoside transporter 1; Slc29a1), show no transition from habitual to goal-directed reward-seeking behaviors upon astrocyte activation, while restoring ENT1 expression in the DMS facilitated this transition. CONCLUSIONS: Our findings reveal that DMS astrocyte activation differentially regulates MSNs' activity and facilitates shifting from habitual to goal-directed reward-seeking behavior.