Neuropharmacology最新文献

Nicotine use remains one of the leading causes of preventable deaths in the United States and, while the prevalence of combustible cigarette use has declined over the past few years, the popularity of electronic nicotine delivery systems continues to rise. Vaping is not without risks, and its long-term effects, particularly in vulnerable populations, remain largely unknown. This study introduces a novel, oronasal-restricted, nicotine vapor self-administration mouse model to investigate the impact of nicotine concentration, genotype, sex, and age on self-administration and behavioral response to nicotine. Our studies show that male and female young adult mice respond to nicotine, demonstrating notable sex-related differences in intake, locomotor sensitization, and somatic withdrawal signs. In addition, we characterized intake in adolescent mice, showing sex differences as well. Finally, we showed genotype-related differences when using β2 knock-out mice, emphasizing the role of the β2 nAChR in nicotine reward and nicotine intake. This new model offers a more targeted approach to studying the potential risks of nicotine vaping in a more relevant and face-valid model compared to traditional whole-body nicotine vapor exposure in rodents.

Alcohol binge drinking has a multitude of effects on CNS function, including changes in inflammatory cytokines such as IL-6 and IL-1β that may contribute to mood fluctuations associated with the intoxication-withdrawal cycle. Widely throughout the brain, including the amygdala, IL-6 mRNA is enhanced during intoxication, whereas IL-1β is initially suppressed during alcohol intoxication, with increased expression seen shortly after ethanol clearance, during acute hangover. Furthermore, induction of neuroimmune genes appears to be muted during adolescence in the amygdala, suggesting a broader functional immaturity of the adolescent neuroimmune system in structures involved in negative affect associated with ethanol exposure. However, neither the effect of IL-6 or IL-1β on synaptic function within the amygdala nor the impact of acute intoxication and withdrawal on these cytokines' function are known. To test this, we used whole-cell patch-clamp electrophysiology to assess the effects of IL-6 and IL-1β on GABA-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) in BLA pyramidal neurons from male rats in early adolescence (P28-40) or adulthood (P70+). These experiments were done in naïve, intoxicated (3-4 h following an intraperitoneal injection of 3.5 g/kg ethanol), and during acute hangover (11-18 h post ethanol injection). In naïve males, we found that IL-6 (10 ng/ml) significantly enhanced sIPSC amplitude only in adults, with no apparent effect in adolescents; this effect of IL-6 in adults was not different during intoxication. Conversely, IL-1β (10 ng/ml) did not alter sIPSC frequency in any group (naïve or hangover adolescents or adults). Unlike our previous work in adult rats, here we found that contextual fear conditioning was not altered in adolescents when conditioned during acute hangover. Together, these observations suggest that IL-6, but not IL-1β, regulation of BLA GABA transmission emerges as a function of age, but is not affected by acute ethanol exposure or hangover for adolescents or adults. Importantly, these findings provide additional evidence to support functional immaturity of the neuroimmune system in adolescence.

Bipolar disorder (BD) is a severe mental illness characterized by recurrent episodes of depression and mania. Lithium is the gold standard pharmacotherapy for BD, but outcomes are variable, and the relevant therapeutic mechanisms underlying successful treatment response remain uncertain. To identify synaptic markers of BD and lithium response, we measured the effects of lithium on induced pluripotent stem cell-derived neurons from BD patients and controls. We determined that baseline expression of synapsin I (SYN1) and PSD-95 is reduced in BD neurons compared to controls. In control neurons, lithium treatment had modest, transient effects increasing SYN1 and PSD-95 expression. In BD neurons, lithium increased SYN1 expression regardless of lithium response history. However, lithium only increased PSD-95 expression selectively in neurons from lithium-responders and not in neurons from lithium non-responders, leading to group differences in the colocalization of SYN1 and PSD-95. In conclusion, this preliminary work indicates synaptic protein markers are associated with BD pathology and correction of post-synaptic protein expression may be an important mechanism underlying lithium response.

Oxidative stress and inflammation play important roles in diabetic-associated cognitive dysfunction (DACD). Swietenolide (Std), isolated from the fruit of Swietenia macrophylla King, exhibits various potent pharmacological activities, including antioxidant, anti-inflammatory, and anti-tumor properties. However, the effects of Std on DACD remains unexplored. We utilized diabetic db/db mice and the hippocampal cell line HT22 to evaluate the effects and underlying molecular mechanisms of Std on DACD. Molecular docking study, western blotting, immunohistochemistry, and enzyme-linked immunosorbent assay analyses were conducted to elucidate the molecular mechanisms involved. We found that Std significantly improved cognitive dysfunction in diabetic mice and increased cell viability in HT22 cells under high glucose condition. The reduction in superoxide dismutase (SOD) enzamy activity and glutathione (GSH) level, along with an increase in malondialdehyde (MDA) induced by high glucose in hippocampus, were reversed by Std treatment. Furthermore, Std effectively diminished the levels of proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Importantly, Std markedly activated the Nrf2 pathway to inhibit the thioredoxin-interacting protein/NOD-like receptor protein 3 (TXNIP/NLRP3) pathways. However, the neuroprotective effect of Std was significantly weakened by Nrf2 inhibitor ML385. These results indicate that Std provides substantial protection against high glucose-induced hippocampal injury by inhibiting the TXNIP/NLRP3 pathways dependent on Nrf2, which may serve as a promising agent for attenuating DACD.

Anhedonia, a transdiagnostic symptom prevalent in depressive and psychotic disorders, poses a significant challenge for pharmacological intervention due to its association with impaired motivation. Understanding how psychotropic drugs can modulate this pathological domain and elucidating the molecular mechanisms underlying such effects are crucial endeavors in psychiatric research. In this study, we aimed to investigate the pro-motivational properties of lurasidone in a rat (Sprague Dawley males) model of anhedonia and to unravel the interplay between lurasidone and the brain regions critical for reward processing. Exposure to unpredictable chronic stress (UCS) led to a marked reduction in motivation, a deficit that was restored by lurasidone treatment at 3 mg/kg, but not at 10 mg/kg. Interestingly, the stress-induced decrease in reactivity to negative stimuli was reversed by both doses of lurasidone. At the molecular level, stressed animals exhibited reduced expression of neuroplastic markers, that was increased following lurasidone administration. Furthermore, UCS exposure impaired the activation of the medial prefrontal cortex (mPFC) and nucleus accumbens (NAc) in response to hedonic stimuli, an effect amended by lurasidone treatment. Additionally, lurasidone restored the impaired phosphorylation of DARPP-32, a key regulator of dopamine signaling, in mPFC and NAc of UCS rats exposed to a hedonic stimulus. These findings underscore the potential of lurasidone in improving various psychopathological domains, like impaired motivation and emotional reactivity, core elements contributing to the disability associated with mental disorders. These effects highlight the therapeutic potential of lurasidone in addressing the intricate behavioral and neurochemical alterations associated with anhedonia and related mood disorders.

Empathy plays a crucial role in social communication and the perception of affective states and behavioral processes. In this study, we observed that empathic interaction with a mouse experiencing pain resulted in decreased mechanical pain thresholds and anxiety-like behaviors in its bystander, though the underlying mechanisms remain unknown. We demonstrated that CD38 expression in the paraventricular nucleus (PVN) was upregulated during empathic pain, and the pain and emotions of CD38 knockout (CD38KO) mice as bystanders were not affected. Furthermore, fiber photometry recordings indicated that calcium activities of PVN neurons were increased during empathic pain. Interestingly, direct chemogenetic inhibition of PVN neurons attenuated the hyperalgesia and anxiety-like behaviors associated with empathic pain. In contrast, activating PVN neurons through chemogenetics in CD38KO mice induced hyperalgesia and anxiety-like effects in empathic pain. Oxytocin levels in PVN were upregulated during empathic pain, while CD38KO mice inhibit the upregulation in OXT levels, confirming that CD38 is involved in releasing brain OXT and that the CD38-OXT system in the PVN plays a role in empathic pain. Collectively, CD38-mediated oxytocin signaling in PVN is closely linked to empathic pain through its effect on the activation of PVN neurons, and it could be viable targets for novel empathic behavior interventions.

Alcohol use disorder is associated with altered function of cortical-amygdala-striatal circuits such as the orbitofrontal cortex (OFC), basolateral amygdala (BLA) and their connections to the dorsal medial striatum (DMS) shown to be involved in goal-directed actions. Using retrobead tracing, we previously reported enhanced excitability of DMS-projecting OFC neurons in mice following 3-to-7-day withdrawal from chronic intermittent ethanol (CIE) exposure. In the same animals, spiking of DMS-projecting BLA neurons was decreased at 3-days post-withdrawal followed by an increase in firing at 7- and 14-days. In the current study, we used transsynaptic labeling and slice electrophysiology to investigate the effects of CIE exposure on DMS neurons that receive convergent inputs from the OFC and BLA. Mice were infused with anterograde transsynaptic AAVs in the OFC (AAV1-Cre) and BLA (AAV1-Flpo) and a Cre-On/Flp-On-YFP AAV in the DMS followed by 4 weekly cycles of Air or CIE vapor exposure. Current-clamp recordings of YFP + DMS^OFC-BLA neurons showed three distinct patterns of firing: regular spiking, regular spiking followed by depolarization block and regular spiking with the appearance of broadened action potentials and plateau potentials at higher current steps (termed FANS). In both male and female mice, withdrawal from CIE exposure significantly increased the excitability of regular spiking neurons as compared to air controls. More subtle effects were observed on FANS neurons with both increases and decreases in firing that were current step and sex-dependent. These findings add to a growing literature demonstrating how neurons within cortical-amygdala-striatal circuits implicated in compulsive/habitual behaviors are impacted by chronic alcohol exposure.

Seizures can lead to cardiac dysfunction. Multiple pathways contribute to this phenomenon, of which the chaperone sigma-1 receptor (S1R) signaling represents a promising nexus between the abnormalities seen in both epilepsy and ensuing cardiac complications. The study explored the potential of Berberine (BER), a promising S1R agonist, in treating epilepsy and associated cardiac abnormalities in a pentylenetetrazol (PTZ) kindling rat model of epilepsy. Male Wistar albino rats received PTZ (35 mg/kg) every other day alone, with BER, with phenytoin (PHT), with both BER and PHT and with both BER and an S1R blocker (NE-100) over 27 days. BER decreased seizure severity and improved hemodynamic parameters. Histopathological abnormalities were more pronounced in the PTZ, and blocker group than in other groups, in heart tissue. In cardiac tissue, BER enhanced the AKT/eNOS signaling pathway and mitigated ferroptosis by boosting the cystine/glutamate transporter/Glutathione/Glutathione Peroxidase 4 (XCT/GSH/GPX4) system and ferritin heavy chain-1 (FTH-1) expression, while reducing iron and Transferrin receptor protein 1 (TFR1) levels. Such effects were largely negated by NE-100 pretreatment. In conclusion, BER shows protective effects on cardiac dysfunction induced by the PTZ kindling model by acting as an S1R agonist and influencing the AKT/eNOS signaling pathway and ferroptosis.

Methamphetamine (METH) is a synthetic drug with potent addictive, relapse, and neurotoxic properties. METH abuse contributes to severe damage to the central nervous system, potentially causing cognitive impairments, behavioral changes, and neurodegenerative diseases. METH-induced neuronal damage is closely related to apoptosis and cell cycle abnormalities, while gene expression regulator microRNAs (miRNAs) may play extensive roles in this progress, but the specific mechanisms remain unclear. We found that the novel miRNA 146 (miR_146) was downregulated in METH-induced apoptosis and cell cycle arrest in tree shrew primary neurons, while the expression of its target gene Tfdp2 was increased after METH exposure. Overexpression of miR_146 or silencing of Tfdp2 significantly alleviated METH-induced cell cycle arrest and apoptosis in primary tree shrew neurons. These findings provide new insights into the role of the miR_146-Tfdp2 axis in METH-induced neurotoxic injury and offer a theoretical basis for miR_146 as potential therapeutic targets in drug abuse.

Hypoactive sexual desire disorder (HSDD) is the most reported sexual dysfunction among premenopausal women worldwide. Bremelanotide, trade name Vyleesi, has been approved by the United States Food and Drug Administration to treat HSDD. However, despite approval, very little is known about its neurobiological mechanism of action. In this study, we utilized a female Syrian hamster model to investigate the effects of bremelanotide on melanocortin receptor expression in the mesolimbic dopamine system and sexual reward. We found that the majority of melanocortin 3 and 4 (MC4R) receptor mRNA is expressed in dopamine neurons in the ventral tegmental area (VTA). Fewer neurons express MC4R in the nucleus accumbens (NAc) or dorsal striatum, where they rarely colocalize with neurons expressing dopamine D1 or D2 receptors. Instead, MC4R mRNA is expressed in nucleus accumbens interneurons. Neither the low nor the high dose of bremelanotide had an effect on the expression of melanocortin receptor mRNA in the mesolimbic dopamine system. Finally, sexual experience resulted in a conditioned place preference (CPP) in female Syrian hamsters, though bremelanotide treatment failed to enhance sexual reward in this test. The results of this study are discussed in conjunction with similar studies in rats, with the conclusion that bremelanotide does not act on the VTA-NAc reward circuit and does not enhance the rewarding effects of sexual interactions.