OBJECTIVE: To investigate the role of α7-nicotinic acetylcholine receptor (α7-nAChR) in the regulation of neuronal activity and expression of synapse-related proteins in the thalamic reticular nucleus (TRN) of insomnia rats treated by acupuncture. METHODS: A total of 36 male Sprague-Dawley (SD) rats of clean grade were randomly divided into a control group, a model group, an acupuncture group, and an acupuncture+antagonist group, with 9 rats in each group. The model group, the acupuncture group, and the acupuncture+antagonist group were treated with intraperitoneal injection of p-chlorophenylalanine (PCPA) to establish insomnia model. After successful modeling, the acupuncture group and the acupuncture+antagonist group received acupuncture at bilateral Neiguan (PC6) and Zusanli (ST36) once daily for 5 consecutive days. Thirty min before each acupuncture session, the acupuncture+antagonist group was intraperitoneally injected with methyllycaconitine citrate (MLA), an α7-nAChR antagonist, at a dosage of 5 mg/kg while the acupuncture group received the same volume of 0.9% sodium chloride solution. The rats' daytime spontaneous activity was observed. Neuronal discharge in the TRN was detected using neuroelectrophysiological methods. Immunofluorescence staining was used to detect parvalbumin-positive (PV⁺) neurons and co-expression of PV⁺ and postsynaptic density protein-95 (PSD-95) in the TRN. RESULTS: Compared with the control group, the model group showed increased daytime spontaneous activity (P<0.01); decreased average fluorescence intensity and positive number of PV⁺ neurons in the TRN (P<0.01); decreased neuronal discharge frequency (P<0.01), prolonged inter-discharge intervals (P<0.01) in the TRN; reduced number of PV⁺/PSD-95 double-positive cells in the TRN (P<0.01). Compared with the model group, the acupuncture group showed decreased daytime spontaneous activity (P<0.01); increased average fluorescence intensity and positive number of PV⁺ neurons in the TRN (P<0.01); increased neuronal discharge frequency (P<0.01), shortened inter-discharge intervals (P<0.01) in the TRN; increased number of PV⁺/PSD-95 double-positive cells in the TRN (P<0.05). Compared with the acupuncture group, the acupuncture+antagonist group exhibited increased daytime spontaneous activity (P<0.01); reduced average fluorescence intensity and positive number of PV⁺ neurons in the TRN (P<0.01); decreased neuronal discharge frequency (P<0.05), prolonged inter-discharge intervals (P<0.05) in the TRN; reduced number of PV⁺/PSD-95 double-positive cells in the TRN (P<0.01). CONCLUSION α7-nAChR are involved in mediating the regulatory effect of acupuncture on circadian rhythm disturbances in PCPA-induced insomnia rats. Blocking α7-nAChR attenuates the activating effect of acupuncture on TRN neurons, and reduces the expression of PSD-95 protein on GABAergic neurons.
Animals ; Male ; Acupuncture Therapy ; alpha7 Nicotinic Acetylcholine Receptor/genetics* ; Rats, Sprague-Dawley ; Rats ; Sleep Initiation and Maintenance Disorders/physiopathology* ; Neurons/metabolism* ; Humans ; Thalamic Nuclei/physiopathology* ; Acupuncture Points ; Disks Large Homolog 4 Protein

The purpose of this study was to investigate the anxiety-like behaviors, circadian rhythms and sleep, and to elucidate the possible underlying mechanisms of the abnormal sleep behavior in Shank3 gene knockout (Shank3-KO) mice. The anxiety-like behaviors were detected by elevated plus-maze (EPM) test, open field test (OFT) and tail suspension test (TST). The circadian rhythms were detected by running wheel test. The electroencephalogram (EEG)/electromyogram (EMG) recordings were performed synchronically by polysomnograph. The distribution of SHANK3 in anterior cingulate cortex (ACC), paraventricular thalamus (PVT), nucleus accumbens (NAc), basolateral amygdala (BLA) and hippocampal CA2 region in wild type (WT) mice was detected by immunofluorescence assay. The protein expression of c-Fos in PVT, ACC and NAc was also detected by immunofluorescence assay during light cycle. The colocalization of c-Fos and vesicular glutamate transporter 2 (Vglut2, a marker for glutamatergic neurons) in the PVT was detected by immunofluorescence double labeling experiment. The results of EPM test showed that, compared with the WT mice, the Shank3-KO mice showed less time in open arms and less number of open arm entries. The results of OFT showed that the Shank3-KO mice showed less time in central area and less number of central area entries. The immobility time of Shank3-KO mice was increased in the TST. The results of running wheel rhythm test showed that the phase shift time of Shank3-KO mice in the continuous dark period was increased. The results of EEG/EMG recording showed that, compared with the WT mice, the duration of wakefulness in Shank3-KO mice was increased and the duration of non-rapid eye movement (NREM) sleep was decreased during light phase; The bout number of wakefulness was increased, the bout number of NREM sleep was decreased, NREM-wake transitions were increased, and wake-NREM transitions were decreased during light phase. SHANK3 was expressed in ACC, PVT, NAc and BLA in the WT mice. The expression of c-Fos in the PVT of Shank3-KO mice was up-regulated 2 h after entering the light phase, and majority of c-Fos was co-localized with Vglut2. These results suggest that the anxiety level of Shank3-KO mice is increased, the regulation of the internal rhythms is decreased, and the bout number of wakefulness is increased during light phase. The glutamatergic neurons in PVT may be involved in the regulation of abnormal sleep behavior in Shank3-KO mice during the light phase.
Animals ; Mice, Knockout ; Mice ; Neurons/metabolism* ; Nerve Tissue Proteins/physiology* ; Male ; Midline Thalamic Nuclei/cytology* ; Circadian Rhythm/physiology* ; Sleep/physiology* ; Anxiety/physiopathology* ; Proto-Oncogene Proteins c-fos/metabolism* ; Vesicular Glutamate Transport Protein 2/metabolism* ; Mice, Inbred C57BL ; Microfilament Proteins

The ventral anterior (VA) nucleus of the thalamus is a major target of the basal ganglia and is closely associated with the pathogenesis of Parkinson's disease (PD). Notably, the VA receives direct innervation from the hypothalamic histaminergic system. However, its role in PD remains unknown. Here, we assessed the contribution of histamine to VA neuronal activity and PD motor deficits. Functional magnetic resonance imaging showed reduced VA activity in PD patients. Optogenetic activation of VA neurons or histaminergic afferents significantly alleviated motor deficits in 6-OHDA-induced PD rats. Furthermore, histamine excited VA neurons via H1 and H2 receptors and their coupled hyperpolarization-activated cyclic nucleotide-gated channels, inward-rectifier K⁺ channels, or Ca²⁺-activated K⁺ channels. These results demonstrate that histaminergic afferents actively compensate for Parkinsonian motor deficits by biasing VA activity. These findings suggest that targeting VA histamine receptors and downstream ion channels may be a potential therapeutic strategy for PD motor dysfunction.
Animals ; Histamine/metabolism* ; Male ; Oxidopamine/toxicity* ; Rats ; Ventral Thalamic Nuclei/physiopathology* ; Rats, Sprague-Dawley ; Disease Models, Animal ; Parkinson Disease/metabolism* ; Neurons/physiology* ; Humans ; Optogenetics

The thalamic reticular nucleus (TRN) plays a crucial role in regulating sensory encoding, even at the earliest stages of visual processing, as evidenced by numerous studies. Orientation selectivity, a vital neural response, is essential for detecting objects through edge perception. Here, we demonstrate that somatostatin (SOM)-expressing and parvalbumin (PV)-expressing neurons in the TRN project to the dorsal lateral geniculate nucleus and modulate orientation selectivity and the capacity for visual information processing in the primary visual cortex (V1). These findings show that SOM-positive and PV-positive neurons in the TRN are powerful modulators of visual information encoding in V1, revealing a novel role for this thalamic nucleus in influencing visual processing.
Animals ; Somatostatin/metabolism* ; Parvalbumins/metabolism* ; Neurons/physiology* ; Thalamic Nuclei/physiology* ; Visual Pathways/physiology* ; Mice ; Mice, Inbred C57BL ; Visual Perception/physiology* ; Male ; Mice, Transgenic ; Visual Cortex/physiology* ; Primary Visual Cortex/cytology*

OBJECTIVE: To determine whether the glutamatergic neurons in the paraventricular nucleus of the thalamus (PVT) is involved in the change of consciousness induced by propofol through a combination of behavioral and electroencephalography (EEG) recordings. METHODS: Healthy male VGluT2-IRES-Cre mice aged 8-12 weeks were used in this experiment. (1) The glutamatergic neurons in the PVT was selectively damaged, and its effect on propofol anesthesia induction and recovery times as well as the energy of EEG in different frequency bands were observed. (2) Optogenetics was utilized to selectively activate or inhibit glutamatergic neurons in the PVT to assess their influence on anesthesia induction and recovery times under propofol as well as the energy of EEG in different frequency bands. RESULTS: (1) Selective ablation of glutamatergic neurons in the PVT significantly delayed recovery from propofol anesthesia with statistical difference as compared with the control group (s: 409.43±117.49 vs. 273.71±51.52, P < 0.05), but had no significant effect on anesthesia induction time. During the recovery phase of propofol, selective ablation of glutamatergic neurons in the PVT exhibited higher α-wave (1-4 Hz) power and reduced β-wave (12-15 Hz) power as compared with the control group. (2) Optogenetic activation of glutamatergic neurons in the PVT significantly prolonged anesthesia induction time under propofol (s: 161.67±29.09 vs. 119.33±18.98, P < 0.05) while significantly shortening the recovery time from propofol anesthesia (s: 208.67±57.19 vs. 288.83±34.52, P < 0.05). During the induction phase of propofol, activation of glutamatergic neurons in PVT reduced α-wave and α-wave (8-12 Hz) power, while during the recovery phase, α-wave power significantly increased as compared with the control group. (3) Optogenetic inhibition of glutamatergic neurons in the PVT delayed recovery from propofol anesthesia (s: 403.50±129.06 vs. 252.83±45.31, P < 0.05), but had no significant effect on induction time. During both the induction phase and recovery phase of propofol, the optogenetic inhibition of glutamatergic neurons in the PVT exhibited increased α-wave power. CONCLUSION Glutamatergic neurons in the PVT are involved in the regulation of propofol anesthesia recovery process.
Animals ; Propofol/pharmacology* ; Mice ; Neurons/physiology* ; Male ; Electroencephalography ; Wakefulness ; Midline Thalamic Nuclei ; Optogenetics

At present, the problem of drug addiction treatment mainly lies in the high relapse rate of drug addicts. Addictive drugs will bring users a strong sense of euphoria and promote drug seeking. Once the drug is withdrawn, there will be withdrawal symptoms such as strong negative emotions and uncomfortable physical reactions. The recurrence of context-induced withdrawal memory is an important reason for drug relapse. Our previous study has shown increased c-Fos expression in prelimbic cortex (PrL) neurons projecting to paraventricular nucleus of the thalamus (PVT) (PrL^-PVT) during conditioned context-induced retrieval of morphine withdrawal memory. However, whether PrL^-PVT neurons are involved in withdrawal memory retrieval and the underlying molecular mechanisms remain unknown. In this study, we used conditioned place aversion (CPA) model combined with in vivo calcium signal recording, chemogenetics and nucleus drug injection methods to investigate the role and molecular mechanism of PrL^-PVT neurons in retrieval of morphine withdrawal memory. The results showed that the calcium signals of PrL^-PVT neurons were significantly enhanced by withdrawal-related context; Inhibition of PrL^-PVT neurons blocked the conditioned context-induced morphine withdrawal memory retrieval; Activation of PrL^-PVT neurons caused animals to escape from the context; After the inhibition of NMDA receptors in the PrL, withdrawal-related context failed to increase c-Fos and Arc expressions in PrL^-PVT neurons. The above results suggest that NMDA receptors in PrL^-PVT neurons are associated with retrieval of morphine withdrawal memory. This study is of great significance for further understanding the neural circuit mechanism of withdrawal memory retrieval as well as the intervention and prevention of drug relapse.
Animals ; Substance Withdrawal Syndrome/physiopathology* ; Morphine/adverse effects* ; Neurons/physiology* ; Receptors, N-Methyl-D-Aspartate/metabolism* ; Male ; Rats ; Paraventricular Hypothalamic Nucleus/metabolism* ; Memory ; Rats, Sprague-Dawley ; Morphine Dependence/physiopathology* ; Midline Thalamic Nuclei/physiology* ; Neural Pathways/metabolism*

Sleep deprivation has been shown to exacerbate pain sensitivity and may contribute to the onset of chronic pain, yet the precise neural mechanisms underlying this association remain elusive. In our study, we explored the contribution of cholinergic neurons within the medial habenula (MHb) to hyperalgesia induced by sleep deprivation in rats. Our findings indicate that the activity of MHb cholinergic neurons diminishes during sleep deprivation and that chemogenetic stimulation of these neurons can mitigate the results. Interestingly, we did not find a direct response of MHb cholinergic neurons to pain stimulation. Further investigation identified the interpeduncular nucleus (IPN) and the paraventricular nucleus of the thalamus (PVT) as key players in the pro-nociceptive effect of sleep deprivation. Stimulating the pathways connecting the MHb to the IPN and PVT alleviated the hyperalgesia. These results underscore the important role of MHb cholinergic neurons in modulating pain sensitivity linked to sleep deprivation, highlighting potential neural targets for mitigating sleep deprivation-induced hyperalgesia.
Animals ; Habenula/physiology* ; Sleep Deprivation/physiopathology* ; Cholinergic Neurons/physiology* ; Male ; Hyperalgesia/physiopathology* ; Rats, Sprague-Dawley ; Rats ; Interpeduncular Nucleus/physiology* ; Pain Threshold/physiology* ; Midline Thalamic Nuclei/physiology* ; Neural Pathways/physiopathology*

The incidence rate of anxiety and depression is significantly higher in patients with inflammatory bowel diseases (IBD) than in the general population. The mechanisms underlying dextran sulfate sodium (DSS)-induced depressive-like behaviors are still unclear. We clarified that IBD mice induced by repeated administration of DSS presented depressive-like behaviors. The paraventricular thalamic nucleus (PVT) was regarded as the activated brain region by the number of c-fos-labeled neurons. RNA-sequencing analysis showed that lipocalin 2 (Lcn2) was upregulated in the PVT of mice with DSS-induced depressive behaviors. Upregulating Lcn2 from neuronal activity induced dendritic spine loss and the secreted protein induced chemokine expression and subsequently contributed to microglial activation leading to blood-brain barrier permeability. Moreover, Lcn2 silencing in the PVT alleviated the DSS-induced depressive-like behaviors. The present study demonstrated that elevated Lcn2 in the PVT is a critical factor for DSS-induced depressive behaviors.
Mice ; Humans ; Animals ; Lipocalin-2/genetics* ; Midline Thalamic Nuclei ; Brain ; Inflammatory Bowel Diseases ; Proto-Oncogene Proteins c-fos ; Mice, Inbred C57BL

Stimulus-specific adaptation (SSA), defined as a decrease in responses to a common stimulus that only partially generalizes to other rare stimuli, is a widespread phenomenon in the brain that is believed to be related to novelty detection. Although cross-modal sensory processing is also a widespread phenomenon, the interaction between the two phenomena is not well understood. In this study, the thalamic reticular nucleus (TRN), which is regarded as a hub of the attentional system that contains multi-modal neurons, was investigated. The results showed that SSA existed in an interactive oddball stimulation, which mimics stimulation changes from one modality to another. In the bimodal integration, SSA to bimodal stimulation was stronger than to visual stimulation alone but similar to auditory stimulation alone, which indicated a limited integrative effect. Collectively, the present results provide evidence for independent cross-modal processing in bimodal TRN neurons.
Acoustic Stimulation ; Animals ; Auditory Perception/physiology* ; Geniculate Bodies ; Rats ; Rats, Wistar ; Thalamic Nuclei/physiology*

BACKGROUND: Anterior thalamic nuclei (ATN) deep brain stimulation (DBS) is an effective method of controlling epilepsy, especially temporal lobe epilepsy. Mossy fiber sprouting (MFS) plays an indispensable role in the pathogenesis and progression of epilepsy, but the effect of ATN-DBS on MFS in the chronic stage of epilepsy and the potential underlying mechanisms are unknown. This study aimed to investigate the effect of ATN-DBS on MFS, as well as potential signaling pathways by a kainic acid (KA)-induced epileptic model. METHODS: Twenty-four rhesus monkeys were randomly assigned to control, epilepsy (EP), EP-sham-DBS, and EP-DBS groups. KA was injected to establish the chronic epileptic model. The left ATN was implanted with a DBS lead and stimulated for 8 weeks. Enzyme-linked immunosorbent assay, Western blotting, and immunofluorescence staining were used to evaluate MFS and levels of potential molecular mediators in the hippocampus. One-way analysis of variance, followed by the Tukey post hoc correction, was used to analyze the statistical significance of differences among multiple groups. RESULTS: ATN-DBS is found to significantly reduce seizure frequency in the chronic stage of epilepsy. The number of ectopic granule cells was reduced in monkeys that received ATN stimulation (P < 0.0001). Levels of 3',5'-cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA) in the hippocampus, together with Akt phosphorylation, were noticeably reduced in monkeys that received ATN stimulation (P = 0.0030 and P = 0.0001, respectively). ATN-DBS also significantly reduced MFS scores in the hippocampal dentate gyrus and CA3 sub-regions (all P < 0.0001). CONCLUSION ATN-DBS is shown to down-regulate the cAMP/PKA signaling pathway and Akt phosphorylation and to reduce the number of ectopic granule cells, which may be associated with the reduced MFS in chronic epilepsy. The study provides further insights into the mechanism by which ATN-DBS reduces epileptic seizures.
Adenosine Monophosphate ; Anterior Thalamic Nuclei ; Cyclic AMP-Dependent Protein Kinases ; Deep Brain Stimulation ; Epilepsy/therapy* ; Epilepsy, Temporal Lobe/therapy* ; Hippocampus ; Humans ; Mossy Fibers, Hippocampal ; Signal Transduction