Psychopharmacology最新文献

Rationale: Stressors play a critical role in the progression of irritable bowel syndrome (IBS). Heterogenous stress causes alterations in our bowel movements which can further cause anxiety and depression-like symptoms, decreasing the ability of individuals worldwide to function in social, academic, and employment settings.

Objectives: This study was aimed to investigate the effect of orally administered Nigella sativa (0.2 mL/kg b.wt.) seed oil (NSSO) on stress-induced IBS, anxiety, and depression-like symptoms in Wistar rats.

Methods: In the present study, modelling IBS induced anxiety and depression-like symptoms in rodents have been employed to correlate the pathophysiological mechanisms behind this disorder. Moreover, evaluation of ameliorative potential of traditionally used NSSO in IBS was also carried out.

Results: Present investigation indicated that acute stress of 1.5 h daily for 20 days induced hyper cortisol, gastrointestinal (GI) hypermotility, diarrhoea, altered levels of short chain fatty acids (SCFAs), and inflammation which are common symptoms of IBS. Furthermore, depression and anxiety-like symptoms were validated in test groups by various behavioral tests and decreased levels of 5-HT-Transporter mRNA gene expression, which are clear indicators of cognitive impairment.

Conclusions: It is possible that these IBS-like symptoms may have contributed to the pathogenesis of cognitive deficits and depression. However, the anti-oxidative, anti-inflammatory, anti-spasmodic, and possibly the anti-anxiolytic properties of NSSO helped in the mitigation of altered gut-brain axis. Because the concurrent treatment of NSSO alleviated the symptoms of modified GI function and consequently, the anxious & depressive behavior of the animals. Overall, this research explored the protective efficacy of NSSO against stress-induced IBS and depression-like symptoms, shedding light on the potential of this natural compound as a therapeutic option in the field of gastroenterology and psychiatry.

Rationale: The literature indicates that nicotine exposure or its discontinuation impair adult hippocampal neurogenesis in rats, though the impact of exercise on this process remains unclear. We have previously shown that disturbances in the number of doublecortin (DCX, a marker of immature neurons)-positive (DCX⁺) cells in the dentate gyrus (DG) of the hippocampus during nicotine deprivation may contribute to a depression-like state in rats.

Objectives: This study aimed to investigate the effect of running on hippocampal neurogenesis, depression-like symptoms, and drug-seeking behaviour during nicotine deprivation.

Methods: The rats were subjected to nicotine (0.03 mg/kg/inf) self-administration via an increasing schedule of reinforcement. After 21 sessions, the animals entered a 14-day abstinence phase during which they were housed in either standard home cages without wheels, cages equipped with running wheels, or cages with locked wheels.

Results: Wheel running increased the number of K_i-67⁺ and DCX⁺ cells in the DG of both nicotine-deprived and nicotine-naive rats. Wheel-running exercise evoked an antidepressant effect on abstinence Day 14 but had no effect on nicotine-seeking behaviour on abstinence Day 15 compared to rats with locked-wheel access.

Conclusions: In summary, long-term wheel running positively affected the number of immature neurons in the hippocampus, which corresponded with an antidepressant response in nicotine-weaned rats. One possible mechanism underlying the positive effect of running on the affective state during nicotine cessation may be the reduction in deficits in DCX⁺ cells in the hippocampus.

Objectives: Substance use disorders (SUDs) represent a significant global health concern, demanding the development of effective pharmacological treatments. To address this, an investigation was conducted to examine the anti-addictive properties of two compounds, (S)-T1 and (S)-T2, which specifically target the α3β4 nicotinic acetylcholine receptor (nAChR).

Methods: The effects of (S)-T1 and (S)-T2 on nicotine-induced conditioned place preference (CPP), locomotor activity and dopamine levels in particular brain regions associated to addiction were investigated and compared in male C57BL/6N mice.

Results: The results demonstrate that neither (S)-T1 nor (S)-T2 induced place conditioning or conditioned place aversion (CPA), suggesting the absence of rewarding or aversive effects. Both compounds significantly attenuated nicotine-induced CPP, with (S)-T1 exhibiting a dose-dependent effect. Furthermore, the co-administration of (S)-T2 (10 mg/kg) with nicotine markedly reduced locomotor activity compared to nicotine treatment alone. Additionally, dopamine analysis revealed that nicotine increased dopamine levels in the nucleus accumbens (NAc) and dorsal striatum, whereas the co-administration of (S)-T1 (1, 3, and 10 mg/kg) and (S)-T2 (10 mg/kg) significantly decreased dopamine levels in these brain regions. No significant effects were observed in the prefrontal cortex (PFC).

Conclusions: These findings suggest that (S)-T1 and (S)-T2 hold promise for treating nicotine addiction by attenuating nicotine-induced CPP and modulating dopamine release in key reward-related brain regions. Further research is needed to gain insights into the underlying mechanisms behind their anti-addictive effects and substantiate their potential for treating nicotine addiction.

Rationale: Traumatic brain injury (TBI) is a critical condition associated with cognitive impairments, including dementia. This study is aimed to construct a long noncoding RNA (lncRNA)-microRNA (miRNA)-messenger RNA (mRNA) network based on bioinformatics analysis and explore molecular mechanisms underlying post-TBI dementia.

Methods: GSE104687 and GSE205661 datasets were downloaded from Gene Expression Omnibus database. Molecular Signatures Database (MSigDB) was used to search oxidative stress-, metabolism- and immune-related genes as the target gene datasets. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes were carried out for functional annotation and enrichment analysis. A TBI mouse model was built to validate the expression of NF2, PLXNA2, NCBP2 and U2SURP in brain tissues.

Results: A total of 7 differentially expressed lncRNAs (DElncRNAs) and 191 DEmRNAs were obtained. Subsequent to differential expression (DE) analysis, a lncRNA-miRNA-mRNA network was established. Notably, 13 key DEmRNAs were identified, potentially playing pivotal roles in the pathogenesis of TBI-induced dementia. By comparing the target gene datasets with 13 DEmRNAs, we identified 4 target genes that overlap with the 13 DEGmRNAs, namely NF2, PLXNA2, NCBP2 and U2SURP. Functional enrichment analysis highlighted the involvement of neuronal projections in the dementia-enriched cluster, while the protective cluster showed associations with protein synthesis and ubiquitination pathways. Importantly, we explored potential drug interventions based on interactions with the above 4 target genes. Additionally, drug interaction prediction showed that NF2 could interact with SELUMETINIB, EVEROLIMUS and TEMSIROLIMUS.

Conclusion: Our study provides insights into the complex regulatory networks underlying post-TBI dementia and suggests a potential role for three classes of drugs in managing dementia symptoms in TBI-induced dementia.

Rationale: Diabetic retinopathy (DR) is linked to an increased risk of psychiatric and neurological conditions, largely due to chronic inflammation, oxidative stress, and microvascular damage associated with the disease. Emerging evidence suggests that Cassia seed extract has significant anti-inflammatory and antioxidant properties. However, the therapeutic potential of obtusin, a major compound in Cassia seed, and its underlying mechanisms remain unclear.

Objective: This study aimed to evaluate the therapeutic efficacy of obtusin in the treatment of DR.

Methods: Db/db mice were treated with obtusin (5 and 10 mg/kg/day) for 12 weeks. Throughout the study, body weight, blood glucose levels, and lipid profiles were monitored. Retinal histopathology and transmission electron microscopy were used to assess the pharmacological effects of obtusin in vivo. Additionally, in vitro assays were conducted on human retinal microvascular endothelial cells cultured under high glucose conditions to explore obtusin's potential role in mitigating DR.

Results: Obtusin treatment in diabetic mice significantly reduced blood glucose levels, improved dyslipidemia, thickened retinal layers, reduced retinal oxidative stress, and inhibited the upregulation of inflammatory cytokines. It also lessened fundus microangiopathy and preserved the retina's normal barrier function. Mechanistic in vitro analysis suggested that obtusin targets the Poldip2-Nox4 oxidative stress axis and the NF-κB-MAPK-VEGFA inflammatory pathway, both of which are implicated in DR.

Conclusions: Our findings suggest that the Poldip2-Nox4 oxidative stress axis and the NF-κB-MAPK-VEGFA inflammatory pathway could be therapeutic targets for obtusin in the treatment of DR and its associated psychiatric and neurological conditions.

Rationale: Due to the numerous limitations of ketamine as a rapid-acting antidepressant drug (RAAD), research is still being conducted to find an effective and safe alternative to this drug. Recent studies indicate that the partial mGlu₅ receptor negative allosteric modulator (NAM), 2-(2-(3-methoxyphenyl)ethynyl)-5-methylpyridine (M-5MPEP), has therapeutic potential as an antidepressant.

Objectives: The study aimed to investigate the potential rapid antidepressant-like effect of M-5MPEP in a mouse model of depression and to determine the mechanism of this action.

Methods: Chronic unpredictable mild stress (CUMS) was used as an animal model of depression. The effects of single and four-day administration of M-5MPEP on CUMS-induced animal behaviors reflecting anhedonia, apathy, and helplessness were studied. Western blot was applied to measure the levels of proteins potentially involved in a rapid antidepressant effect, including mammalian target of rapamycin (mTOR), eukaryotic elongation factor 2 (eEF2), tropomyosin receptor kinase B (TrkB), and serotonin transporter (SERT), both in the hippocampus and the prefrontal cortex (PFC). Furthermore, excitatory synaptic transmission and long-term potentiation (LTP) were measured in the medial PFC (mPFC).

Results: We showed that M-5MPEP administration for four consecutive days abolished CUMS-induced apathy- and anhedonia-like symptoms in a mouse model of depression. We also found that these effects were accompanied by changes in hippocampal TrkB levels and mTOR and eEF2 levels in the PFC. Using electrophysiological techniques, we showed that the four-day M-5MPEP treatment reversed chronic stress-induced increases in excitatory synaptic potential and CUMS-impaired LTP in the mPFC.

Conclusions: Partial mGlu₅ receptor NAM, M-5MPEP, appears to be a potentially effective new RAAD and deserves further study.

Rationale: Ketamine, a non-competitive NMDA receptor antagonist, produces antidepressant effects at subanesthetic doses. The therapeutic effect, however, is often accompanied by cognitive side effects, including memory impairments. Yet, the specific effects of ketamine on different processes of implicit and explicit memory remain to be elucidated.

Objectives: We examined the effect of an antidepressant dose of ketamine (10 mg/kg, IP) on the encoding, retrieval, and modulation processes of fear memory and spatial memory in adult Wistar rats.

Methods: Ketamine was administered before the fear acquisition, retrieval, or extinction procedures in a Pavlovian fear conditioning task. In another set of experiments, it was administered before the training, probe trial, or reversal training phases of the Morris Water Maze (MWM).

Results: The antidepressant dose of ketamine partially impaired fear extinction when administered before the acquisition or retrieval. In contrast, it facilitated memory modulation and decreased the escape latency in the first day of reversal training in the MWM when administered before the training or reversal training sessions. Encoding or retrieval performance in either type of memory was not affected.

Conclusions: These findings show that ketamine does not impair the acquisition or retrieval processes of cued fear or spatial memory; but exerts differential effects on memory modulation of these implicit and explicit memory paradigms, by disrupting fear extinction and facilitating reversal spatial learning.

Rationale: Given the nascency of tobacco-free oral nicotine pouches (NPs) and the heterogeneity of commercially available NP brands, there is a need for scientific evaluation of different NP formulations. Nordic Spirit, novel NPs are distinguished by their unique composition.

Objectives: To characterize blood nicotine delivery, pharmacokinetics (PK), subjective and physiological effects and to monitor safety of three Nordic Spirit NPs (6 mg, 9 mg and 11.2 mg/pouch) compared with LD tobacco snus (11.2 mg/pouch) and Nicorette® gum (4 mg/unit) following single 30 min use.

Methods: This was a randomized, open-label, ten-sequence, single-use, cross-over clinical study with 30 healthy adult Swedish snus users.

Results: Peak nicotine concentrations (C_max) ranged from 10.92 to 17.32 ng/mL for the three Nordic Spirit NPs, with a trend toward dose proportionality, and 8.18 ng/mL and 9.23 ng/mL for the LD snus and Nicorette® gum comparators, respectively. Peak concentration for Nordic Spirit NPs was reached (T_max) after 30 to 38 min, and after 45 min for LD snus and Nicorette® gum. No notable safety concerns were observed after single use for any of the study products.

Conclusions: Delivery of nicotine from the three Nordic Spirit NPs appeared to be nicotine content-dependent, based on C_max and AUC. The amount of nicotine extracted showed positive correlation with the reported C_max and AUC. For Nordic Spirit NPs, T_max was immediately after end of use. The characteristics of Nordic Spirit NPs were found to be favourable for profiling NP nicotine delivery and safety in human use, and for further product development. ISRCTN registry study no. ISRCTN75583947.

Rationale: Tobacco monoamine oxidase (MAO) inhibitors have long been suspected of influencing tobacco dependence, but direct evidence of their effects has been difficult to obtain. Recently we have identified two new groups of monoamine oxidase inhibitors, hydroquinones and polyunsaturated fatty acids (linoleic and linolenic acid), abundant in tobacco smoke.

Objectives: To test, in relevant animal models, whether the combined effect of these inhibitors is sufficient to affect addictive responses to nicotine.

Methods: Here we report the first tests of the effects of mixed tobacco MAO inhibitors in three animal behavioural tests relevant to nicotine addiction, conditioned place preference, locomotor sensitisation and nicotine self-administration. Inhibitors used were the aforementioned linoleic and linolenic acid, and catechol, 4-ethylcatechol, 4-methyl catechol and hydroquinone, together with the already known inhibitors harman and norharman. They were administered together in the ratios found in tobacco smoke.

Results: In conditioned place preference and in self-administration tests the addition of these tobacco MAO inhibitors significantly increased responding to nicotine and motivation to self-administer nicotine, supporting the hypothesis that inhibition of MAO enzymes in the brain enhances addictive responses such as that for nicotine. The combined MAO inhibitors without nicotine did not cause increased locomotor activity and did not induce a place conditioned response.

Conclusions: Our results show that the combined effect of three groups of major MAO inhibitors present in tobacco smoke can enhance the addictive responses to nicotine in rats. There is no evidence from this study that these MAO inhibitors are addictive in themselves.

Rationale: There is a debate about whether doctors should prophylactically use benzhexol in schizophrenic patients to reduce the occurrence of extrapyramidal side effects (EPS) after risperidone treatment.

Objectives: We conducted a prospective animal model to explore the efficacy and safety of the prophylactic use of benzhexol after risperidone treatment and the mechanism of the process.

Methods: C57/BL mice were injected with MK-801 (0.5 mg/kg, i.p.) once a day for two weeks. The open field test (OFT) and the novel object recognition test (NORT) assessed the schizophrenia-like behavior of mice. After four weeks of treatment with benzhexol (10 mg/kg, i.g.) and risperidone (3 mg/kg, i.g.), the inclined screen test (IST), rotarod test (RT), open field test (OFT), novel object recognition test (NORT) and the Morris water maze test (MWM) were conducted successively. The expression of BDNF, p-Tau, and Tau in the hippocampus was detected by Western blot assay.

Results: We showed that benzhexol can significantly attenuate risperidone-induced motor coordination impairments and catalepsy and did not affect the efficacy of risperidone in reducing spontaneous activity. Notably, the prophylactic use of benzhexol reduced the recognition memory and spatial memory in MK-801-induced model mice after risperidone. In addition, benzhexol increased the ratio of p-Tau/Tau and decreased BDNF expression levels in the hippocampus.

Conclusions: We found that the prophylactic use of benzhexol can reduce the occurrence of EPS and does not affect the efficacy of risperidone in the treatment of positive symptoms. Benzhexol may impair cognitive function but did not cause further deterioration of cognitive function in MK-801 mice.