Whole-brain monosynaptic inputs to lateral periaqueductal gray glutamatergic neurons in mice

Compound 38, a novel potent and selective antagonist of adenosine A2A receptor, enhances arousal in mice

Adenosine A2A receptor (A2AR) plays a pivotal role in the regulation of sleep-wake behaviors. We previously reported an A2AR selective antagonist compound 38 with an IC50 value of 29.0 nM. In this study, we investigated its effect on sleep-wake regulation in mice. Wild-type (WT) mice were administered compound 38 (3.3, 5.0, 7.5, 15, 30 mg/kg, i.p.) at 9:00, and electroencephalography and electromyography were simultaneously recorded. We showed that administration of compound 38 exhibited a dose-dependent effect on wakefulness promotion. To investigate the impact of compound 38 on sleep rebound, we conducted a 6 h (13:00-19:00) sleep deprivation experiment. We found that administration of compound 38 (30 mg/kg) produced a wakefulness-promoting effect lasting for 1 h. Subsequently, we explored the critical role of A2AR in the wakefulness-promoting effect of compound 38 using A2AR knockout (KO) mice and their WT littermates. We found that compound 38 enhanced wakefulness in WT mice, but did not have an arousal-promoting effect in A2AR KO mice, suggesting that the arousal-promoting effect of compound 38 was mediated by A2AR. We conducted immunohistochemistry and selectively ablated A2AR-positive neurons using cell type-specific caspase-3 expression, which revealed an essential role of A2AR-positive neurons in the nucleus accumbens shell for the arousal-promoting effect of compound 38. In conclusion, as a novel A2AR antagonist, compound 38 promotes wakefulness in mice via the A2AR and exhibits promising applications for further advancements in the field of sleep-wake disorders.

A sensory-motor-sensory circuit underlies antinociception ignited by primary motor cortex in mice

Sensory-motor integration is crucial in the processing of chronic pain. The primary motor cortex (M1) is emerging as a promising target for chronic pain treatment. However, it remains elusive how nociceptive sensory inputs influence M1 activity and how rectifying M1 defects, in turn, regulates pain processing at cellular and network levels. We show that injury/inflammation leads to hypoactivity of M1Glu pyramidal neurons by excitation-inhibition imbalance between the primary somatosensory cortex (S1) and the M1. The impaired M1 output further weakens inputs to excitatory parvalbumin neurons of the lateral hypothalamus (LHPV) and impairs the descending inhibitory system, hence exacerbating spinal nociceptive sensitivity. When rectifying M1 defects with repetitive transcranial magnetic stimulation (rTMS), the imbalance of the S1-M1 microcircuitry can be effectively reversed, which aids in restoring the ability of the M1 to trigger the descending inhibitory system, thereby alleviating nociceptive hypersensitivity. Thus, a sensory-motor-sensory loop is identified for pain-related interactions between the sensory and motor systems and can be potentially exploited for treating chronic pain.

Correlation Between Systemic Immune Inflammatory Index and Suicidal Attempt in Patients with First-Episode Untreated Depression and its Risk Factors

Objective

To examine the relationship between the systemic immune inflammatory index (SII) and suicide attempts (SA) in individuals experiencing their first episode of major depressive disorder (MDD).

Methods

A retrospective analysis of 338 MDD patients (2020-2023) at the First Affiliated Hospital of Wannan Medical College and 76 healthy controls (HC) was conducted. MDD patients were categorized based on their history of SA. Differences in SII and clinical characteristics were analyzed, and a receiver operating characteristic (ROC) curve was used to determine the optimal SII cutoff for predicting SA. Binary logistic regression identified independent risk factors associated with SA.

Results

MDD patients exhibited higher levels of neutrophils, platelets, and SII compared to HC (all p<0.05). SA Patients had higher HDRS scores, neutrophil counts, mean platelet counts, and SII values compared to those without SA (all p<0.05). ROC analysis identified an optimal SII cutoff of 515.3, with 67% sensitivity, 70% specificity, and an area under the curve (AUC) of 0.692. After adjusting for gender, age, body mass index, disease duration, and quality of life, individuals with elevated SII values were 8.318 times more likely to have recent SA (OR=8.318, 95% CI: 3.767-17.546, p<0.05). Patients with high SII values were 14.101 times more likely to have recent SA compared to those with low SII values (OR=14.101, 95% CI: 5.356-34.235, p<0.05). However, high SII was not identified as a significant risk factor for previous SA (OR=0.607, 95% CI: 0.061-4.961, p>0.05).

Conclusion

SII represents a cost-effective and accessible method for evaluating suicide risk in patients with MDD.

CART neurons in the hypothalamic ventral premammillary nucleus (PMv) in rats mediate maternal, but not inter-male aggression

Compared to males, aggression is less frequently noticed in females. Fierce maternal-aggression to thwart the attack/threat of male-conspecific/intruder is transiently expressed as she defends her pups. The odor cues emanated by the intruder provoke aggressive behavior by robustly activating the ventral-premammillary nucleus (PMv) in the hypothalamic-attack area (HAA). But, how PMv activation triggers aggression is unclear. In view of neuropeptide CART's potential to reconfigure neural circuits for behavioral demands, occurrence throughout aggression-circuitry, and abundance particularly in PMv, we test the role of PMvCART in maternal and inter-male aggression in the rats. Males/dams actively attacked the intruder; virgin-females did not. The dams/males without intruder showed isolated cFos-cells in PMv, but intruder's presence triggered cFos-activation in different PMv-subdivisions in dams/males. Compared to dams without intruder, confrontation with intruder robustly activated PMvCART-neurons, augmented CART-ir in ventral-PMv and cart-mRNA in PMv-containing tissues in dams. Conversely, in males, intruder's presence activated lateral-PMv CART neurons, but CART-levels remained unaltered. Intra-PMv CART-siRNA administration suppressed maternal-aggression but male-aggression was unaffected. Since PMv is strongly connected with ventrolateral-ventromedial hypothalamus (VMHvl) and medial-preoptic nucleus (MPN), we test whether CART-signalling to these nuclei triggers maternal-aggression. While VMHvl showed stronger CARTergic-axonal input than MPN, immunoneutralization of CART in VMHvl but not MPN, blocked maternal-aggression. CART may drive the circuit beyond HAA since VMHvl neurons contacted by CART-axons project to periaqueductal-gray. We identify engagement of vPMv and lPMv during maternal and inter-male aggression, respectively, and CART as a key mediator in PMv-VMHvl-pathway to express maternal-aggression in rats.Significance statement Pregnant/lactating rat transiently become fiercely aggressive to protect her pups when challenged by an intruder. The neural mechanism underlying this transitory expression of aggressive behavior is not clear. We identify the role of neuropeptide CART-containing neurons in the hypothalamic premammillary nucleus (PMv) in dams that gives her the behavioral flexibility to display maternal-aggression. A subset of PMvCART neurons in dams shows dramatic activation when provoked by an intruder while silencing of these neurons suppressed maternal- but not male-male aggression. Further, CART signals the ventrolateral part of the ventromedial hypothalamus to trigger aggression in dams. The study shows CART as a novel messenger in aggression circuitry and PMvCART a key regulator of maternal-aggression.

Activation of the periaqueductal gray controls respiratory output through a distributed brain network

Introduction

The periaqueductal gray (PAG) has been previously established to play a key role in producing the vital changes in respiration occurring in response to threat. However, it is not fully understood how PAG activation alters the ongoing respiratory output, nor it is understood which pathways mediate these effects, as several regions have been previously identified to influence respiratory activity.

Methods

We used optogenetic tools in conjunction with EMG recordings of inspiratory and expiratory musculature to determine how PAG activation on short (250 ms) and longer (10-15 s) timescales alters respiratory muscle activity. Through cFOS mapping, we also identified key downstream brain regions which were likely modulated by PAG activation including the preBötzinger Complex (preBötC) and the lateral parafacial area (pFL). We then stimulated PAG terminals in those regions to determine whether their activity can account for the observed effects of PAG stimulation.

Results

Directly stimulating the PAG resulted in prominent changes to all recorded muscle activities and reset the breathing rhythm in either a phase-independent or phase-dependent manner. In contrast, stimulating PAG terminals in either preBötC or pFL with long or shorter timescale stimuli could not completely replicate the effects of direct PAG stimulation and also did not produce any respiratory reset.

Conclusions

Our results show that the effects of PAG activity on respiration are not mediated solely by PAG inputs to either the preBötC or pFL and more likely involve integration across a larger network of brainstem areas.

Lateral periaqueductal gray participate in the regulation of irritable bowel syndrome induced by chronic restraint stress

Irritable bowel syndrome (IBS) is a functional bowel disorder defined by recurrent abdominal pain, coupled with irregular bowel habits and alterations in the frequency as well as the consistency of stool. At present, IBS is considered as a disease of gut-brain interaction, and an increasing number of studies are focusing on the brain-gut axis. However, the brain regions associated with IBS have not been fully studied yet. In this study, we utilized the chronic restraint stress (CRS) model to evoke IBS-like symptoms in mice, which were accompanied by anxiety-like behaviors and hyperalgesia. Through cFOS staining, we observed the activation of the lateral periaqueductal gray (LPAG) in the mice after CRS. By inhibiting the activity of the LPAG through tetanus toxin or chemogenetics, we found that IBS-like symptoms could be relieved, whereas chemogenetic activation of the LPAG induced IBS-like symptoms. Finally, we utilized the classic analgesic drug sufentanil and found that it could alleviate CRS-induced IBS-like symptoms.

Helicid Alleviates Neuronal Apoptosis of Rats with Depression-Like Behaviors by Downregulating lncRNA-NONRATT030918.2

Helicid (HEL) has been found to possess antidepressant pharmacological activity. The paper was to testify to the precise molecular mechanism through which HEL regulates lncRNA-NONRATT030918.2 to exert an antidepressant impression in depression models. A depression model stimulated using chronic unpredictable mild stress (CUMS) was created in rats, and the depressive state of the rats was assessed through behavioral experiments. Additionally, an in vitro model of PC12 cells induced by corticosterone (CORT) was established, and cytoactive was tested using the CCK8. The subcellular localization of the NONRATT030918.2 molecule was confirmed through a fluorescence in situ hybridization experiment. The relationship between NONRATT030918.2, miRNA-128-3p, and Prim1 was analyzed using dual-luciferase reporter gene assay, RNA Binding Protein Immunoprecipitation assay, and RNA pull-down assay. The levels of NONRATT030918.2, miRNA-128-3p, and Prim1 were tested using Q-PCR. Furthermore, the levels of Prim1, Bax, Bcl-2, and caspase3 were checked through Western blot. The HEL can alleviate the depression-like behavior of CUMS rats (P < 0.05), and reduce the mortality of hippocampal via downregulating the level of NONRATT030918.2 (P < 0.05). In CORT-induced PC12 cells, intervention with HEL led to decreased expression of NONRATT030918.2 and Prim1 (P < 0.05), as well as increased expression of miRNA-128-3p (P < 0.05). This suggests that HEL regulates the expression of NONRATT030918.2 to upregulate miRNA-128-3p (P < 0.05), which in turn inhibits CORT-induced apoptosis in PC12 cells by targeting Prim1 (P < 0.05). The NONRATT030918.2/miRNA-128-3p/Prim1 axis could potentially serve as a crucial regulatory network for HEL to exert its neuroprotective effects.

Commissural and monosynaptic inputs to medial vestibular nucleus GABAergic neurons in mice

Objective

MVN GABAergic neurons is involved in the rebalance of commissural system contributing to alleviating acute peripheral vestibular dysfunction syndrome. This study aims to depict monosynaptic inputs to MVN GABAergic neurons.

Methods

The modified rabies virus-based retrogradation method combined with the VGAT-IRES-Cre mice was used in this study. Moreover, the commissural connections with MVN GABAergic neurons were analyzed.

Results

We identified 60 nuclei projecting to MVN GABAergic neurons primarily distributed in the cerebellum and the medulla. The uvula-nodulus, gigantocellular reticular nucleus, prepositus nucleus, intermediate reticular nucleus, and three other nuclei sent dense inputs to MVN GABAergic neurons. The medial (fastigial) cerebellar nucleus, dorsal paragigantocellular nucleus, lateral paragigantocellular nucleus and 10 other nuclei sent moderate inputs to MVN GABAergic neurons. Sparse inputs to MVN GABAergic neurons originated from the nucleus of the solitary tract, lateral reticular nucleus, pedunculopontine tegmental nucleus and 37 other nuclei. The MVN GABAergic neurons were regulated by the contralateral MVN, lateral vestibular nucleus, superior vestibular nucleus, and inferior vestibular nucleus.

Conclusion

Our study contributes to further understanding of the vestibular dysfunction in terms of neural circuits and search for new strategies to facilitate vestibular compensation.

Vestibular Neurostimulation for Parkinson's Disease: A Novel Device-Aided Non-Invasive Therapeutic Option

Dopaminergic replacement therapy remains the mainstay of symptomatic treatment for Parkinson's disease (PD), but many unmet needs and gaps remain. Device-based treatments or device-aided non-oral therapies are typically used in the advanced stages of PD, ranging from stereotactic deep brain stimulation to levodopa or apomorphine infusion therapies. But there are concerns associated with these late-stage therapies due to a number of procedural, hardware, or long-term treatment-related side effects of these treatments, and their limited nonmotor benefit in PD. Therefore, there is an urgent unmet need for low-risk adjuvants or standalone therapies which can address the range of burdensome motor and nonmotor symptoms that occur in PD. Recent studies suggest that non-invasive neurostimulation of the vestibular system may be able to address these gaps through the stimulation of the vestibular brainstem sensory network which extensively innervates brain regions, regulating both motor and a range of nonmotor functions. Therapeutic non-invasive vestibular stimulation is a relatively modern concept that may potentially improve a broad range of motor and nonmotor symptoms of PD, even at early stages of the disease. Here, we review previous studies supporting the therapeutic potential of vestibular stimulation for the treatment of PD and discuss ongoing clinical trials and potential areas for future investigations.

Gamma-aminobutyric acid and glutamate/glutamine levels in the dentate nucleus and periaqueductal gray in new daily persistent headache: a magnetic resonance spectroscopy study

BACKGROUND

Magnetic resonance spectroscopy (MRS) studies have indicated that the imbalance between gamma-aminobutyric acid (GABA) and glutamate/glutamine (Glx) levels was the potential cause of migraine development. However, the changes in the GABA and Glx levels in patients with New daily persistent headache (NDPH) remain unclear. This study aimed to investigate the changes in GABA and Glx levels in the periaqueductal gray (PAG) and dentate nucleus (DN) in patients with NDPH using the MEGA-PRESS sequence.

METHODS

Twenty-one NDPH patients and 22 age- and sex-matched healthy controls (HCs) were included and underwent a 3.0T MRI examination, using the MEGA-PRESS sequence to analyze GABA and Glx levels of PAG and DN. The correlations between these neurotransmitter levels and clinical characteristics were also analyzed.

RESULTS

There were no significant differences in the GABA+/Water, GABA+/Cr, Glx/Water, and Glx/Cr levels in both PAG and DN between the two groups (all p > 0.05). Moderate-severe NDPH patients had lower levels of Glx/Water (p = 0.034) and Glx/Cr (p = 0.012) in DN than minimal-mild NDPH patients. In patients with NDPH, higher Glx/Water levels in the PAG (r=-0.471, p = 0.031, n = 21) and DN (r=-0.501, p = 0.021, n = 21) and higher Glx/Cr levels in DN (r=-0.483, p = 0.026, n = 21) were found to be correlated with lower Visual Analogue Scale scores. Additionally, a positive correlation was observed between the GABA+/Cr levels in the DN and the Generalized Anxiety Disorder-7 scores (r = 0.519, p = 0.039, n = 16).

CONCLUSIONS

The results of this study indicated that the GABA and Glx levels in the PAG and DN may not be the primary contributor to the development of NDPH. The correlations between certain clinical scales and the neurotransmitter levels may be derived from the NDPH related symptoms.

Effects of cognitive training and behavior modification on aggressive behavior and sleep quality in schizophrenia

Background

Schizophrenia (SCZ) is linked to a heightened risk of impulsive aggression and disturbances in sleep patterns. Cognitive and social cognitive impairments have been connected to aggression, with social cognitive deficits appearing to play a more immediate role. In this investigation, we conducted a retrospective analysis of the impact of cognitive training and sleep interventions on aggressive behavior and the quality of sleep among individuals with SCZ who were hospitalized.

Methods

This study divided 80 hospitalized patients into two groups according to medical advice, namely the normal group and the study group. The control group received routine drug treatment and education; The research group implemented cognitive training and sleep intervention based on the normal group. Collect basic clinical data, aggressive behavior indicators, and sleep quality indicators.

Results

There is no difference in the basic information statistics between the two groups. Both groups can reduce aggressive behavior and improve sleep quality. In the study group, there was a notable decrease in aggressive behavior compared to the control group. Furthermore, the sleep quality in the study group exhibited significant improvement when compared to the control group.

Conclusion

Cognitive training and sleep intervention have been proven to be effective nonpharmacological treatments, effectively reducing aggressive behavior and improving sleep quality.

The contribution of periaqueductal gray in the regulation of physiological and pathological behaviors

Periaqueductal gray (PAG), an integration center for neuronal signals, is located in the midbrain and regulates multiple physiological and pathological behaviors, including pain, defensive and aggressive behaviors, anxiety and depression, cardiovascular response, respiration, and sleep-wake behaviors. Due to the different neuroanatomical connections and functional characteristics of the four functional columns of PAG, different subregions of PAG synergistically regulate various instinctual behaviors. In the current review, we summarized the role and possible neurobiological mechanism of different subregions of PAG in the regulation of pain, defensive and aggressive behaviors, anxiety, and depression from the perspective of the up-down neuronal circuits of PAG. Furthermore, we proposed the potential clinical applications of PAG. Knowledge of these aspects will give us a better understanding of the key role of PAG in physiological and pathological behaviors and provide directions for future clinical treatments.