Method for GPU-based spectral data cube reconstruction of integral field snapshot imaging spectrometers.

In this paper, the principles of spectral data cube reconstruction based on an integral field snapshot imaging spectrometer and GPU-based acceleration are presented. The primary focus is on improving the reconstruction algorithm using GPU parallel computing technology to enhance the computational efficiency for real-time applications. And the computational tasks of the spectral reconstruction algorithm were transferred to the GPU through program parallelization and memory optimization, resulting in significant performance gains. Experimental results indicate that the average processing time of the GPU-based parallel algorithm is approximately 29.43 ms, showing a substantial acceleration ratio of about 14.27 compared to the traditional CPU serial algorithm with an average processing time of around 420.46 ms. The study aims to refine the GPU parallelization algorithm for continued improvement in computational efficiency and overall performance. The anticipated applications of this research include providing crucial technical support for the perception and monitoring of crop growth traits in agricultural production, contributing to the modernization and advancement of intelligence in the field.

CRF regulates pain sensation by enhancement of corticoaccumbal excitatory synaptic transmission.

Both peripheral and central corticotropin-releasing factor (CRF) systems have been implicated in regulating pain sensation. However, compared with the peripheral, the mechanisms underlying central CRF system in pain modulation have not yet been elucidated, especially at the neural circuit level. The corticoaccumbal circuit, a structure rich in CRF receptors and CRF-positive neurons, plays an important role in behavioral responses to stressors including nociceptive stimuli. The present study was designed to investigate whether and how CRF signaling in this circuit regulated pain sensation under physiological and pathological pain conditions. Our studies employed the viral tracing and circuit-, and cell-specific electrophysiological methods to label the CRF-containing circuit from the medial prefrontal cortex to the nucleus accumbens shell (mPFCCRF-NAcS) and record its neuronal propriety. Combining optogenetic and chemogenetic manipulation, neuropharmacological methods, and behavioral tests, we were able to precisely manipulate this circuit and depict its role in regulation of pain sensation. The current study found that the CRF signaling in the NAc shell (NAcS), but not NAc core, was necessary and sufficient for the regulation of pain sensation under physiological and pathological pain conditions. This process was involved in the CRF-mediated enhancement of excitatory synaptic transmission in the NAcS. Furthermore, we demonstrated that the mPFCCRF neurons monosynaptically connected with the NAcS neurons. Chronic pain increased the protein level of CRF in NAcS, and then maintained the persistent NAcS neuronal hyperactivity through enhancement of this monosynaptic excitatory connection, and thus sustained chronic pain behavior. These findings reveal a novel cell- and circuit-based mechanistic link between chronic pain and the mPFCCRF → NAcS circuit and provide a potential new therapeutic target for chronic pain.

An Ascending Excitatory Circuit from the Dorsal Raphe for Sensory Modulation of Pain.

The dorsal raphe nucleus (DRN) is an important nucleus in pain regulation. However, the underlying neural pathway and the function of specific cell types remain unclear. Here, we report a previously unrecognized ascending facilitation pathway, the DRN to the mesoaccumbal dopamine (DA) circuit, for regulating pain. Chronic pain increased the activity of DRN glutamatergic, but not serotonergic, neurons projecting to the ventral tegmental area (VTA) (DRNGlu-VTA) in male mice. The optogenetic activation of DRNGlu-VTA circuit induced a pain-like response in naive male mice, and its inhibition produced an analgesic effect in male mice with neuropathic pain. Furthermore, we discovered that DRN ascending pathway regulated pain through strengthened excitatory transmission onto the VTA DA neurons projecting to the ventral part of nucleus accumbens medial shell (vNAcMed), thereby activated the mesoaccumbal DA neurons. Correspondingly, optogenetic manipulation of this three-node pathway bilaterally regulated pain behaviors. These findings identified a DRN ascending excitatory pathway that is crucial for pain sensory processing, which can potentially be exploited toward targeting pain disorders.

A common neuronal ensemble in nucleus accumbens regulates pain-like behaviour and sleep.

A comorbidity of chronic pain is sleep disturbance. Here, we identify a dual-functional ensemble that regulates both pain-like behaviour induced by chronic constrictive injury or complete Freund's adjuvant, and sleep wakefulness, in the nucleus accumbens (NAc) in mice. Specifically, a select population of NAc neurons exhibits increased activity either upon nociceptive stimulation or during wakefulness. Experimental activation of the ensemble neurons exacerbates pain-like (nociceptive) responses and reduces NREM sleep, while inactivation of these neurons produces the opposite effects. Furthermore, NAc ensemble primarily consists of D1 neurons and projects divergently to the ventral tegmental area (VTA) and preoptic area (POA). Silencing an ensemble innervating VTA neurons selectively increases nociceptive responses without affecting sleep, whereas inhibiting ensemble-innervating POA neurons decreases NREM sleep without affecting nociception. These results suggest a common NAc ensemble that encodes chronic pain and controls sleep, and achieves the modality specificity through its divergent downstream circuit targets.

Disinhibition of Mesolimbic Dopamine Circuit by the Lateral Hypothalamus Regulates Pain Sensation.

Our recent study demonstrated the critical role of the mesolimbic dopamine (DA) circuit and its brain-derived neurotropic factor (BDNF) signaling in mediating neuropathic pain. The present study aims to investigate the functional role of GABAergic inputs from the lateral hypothalamus (LH) to the ventral tegmental area (VTA; LHGABA→VTA) in regulating the mesolimbic DA circuit and its BDNF signaling underlying physiological and pathologic pain. We demonstrated that optogenetic manipulation of the LHGABA→VTA projection bidirectionally regulated pain sensation in naive male mice. Optogenetic inhibition of this projection generated an analgesic effect in mice with pathologic pain induced by chronic constrictive injury (CCI) of the sciatic nerve and persistent inflammatory pain by complete Freund's adjuvant (CFA). Trans-synaptic viral tracing revealed a monosynaptic connection between LH GABAergic neurons and VTA GABAergic neurons. Functionally, in vivo calcium/neurotransmitter imaging showed an increased DA neuronal activity, decreased GABAergic neuronal activity in the VTA, and increased dopamine release in the NAc, in response to optogenetic activation of the LHGABA→VTA projection. Furthermore, repeated activation of the LHGABA→VTA projection was sufficient to increase the expression of mesolimbic BDNF protein, an effect seen in mice with neuropathic pain. Inhibition of this circuit induced a decrease in mesolimbic BDNF expression in CCI mice. Interestingly, the pain behaviors induced by activation of the LHGABA→VTA projection could be prevented by pretreatment with intra-NAc administration of ANA-12, a TrkB receptor antagonist. These results demonstrated that LHGABA→VTA projection regulated pain sensation by targeting local GABAergic interneurons to disinhibit the mesolimbic DA circuit and regulating accumbal BDNF release.SIGNIFICANCE STATEMENT The mesolimbic dopamine (DA) system and its brain-derived neurotropic factor (BDNF) signaling have been implicated in pain regulation, however, underlying mechanisms remain poorly understood. The lateral hypothalamus (LH) sends different afferent fibers into and strongly influences the function of mesolimbic DA system. Here, utilizing cell type- and projection-specific viral tracing, optogenetics, in vivo calcium and neurotransmitter imaging, our current study identified the LHGABA→VTA projection as a novel neural circuit for pain regulation, possibly by targeting the VTA GABA-ergic neurons to disinhibit mesolimbic pathway-specific DA release and BDNF signaling. This study provides a better understanding of the role of the LH and mesolimbic DA system in physiological and pathological pain.

Neural and molecular investigation into the paraventricular thalamic-nucleus accumbens circuit for pain sensation and non-opioid analgesia.

The paucity of medications with novel mechanisms for pain treatment combined with the severe adverse effects of opioid analgesics has led to an imperative pursuit of non-opioid analgesia and a better understanding of pain mechanisms. Here, we identify the putative glutamatergic inputs from the paraventricular thalamic nucleus to the nucleus accumbens (PVTGlut→NAc) as a novel neural circuit for pain sensation and non-opioid analgesia. Our in vivo fiber photometry and in vitro electrophysiology experiments found that PVTGlut→NAc neuronal activity increased in response to acute thermal/mechanical stimuli and persistent inflammatory pain. Direct optogenetic activation of these neurons in the PVT or their terminals in the NAc induced pain-like behaviors. Conversely, inhibition of PVTGlut→NAc neurons or their NAc terminals exhibited a potent analgesic effect in both naïve and pathological pain mice, which could not be prevented by pretreatment of naloxone, an opioid receptor antagonist. Anterograde trans-synaptic optogenetic experiments consistently demonstrated that the PVTGlut→NAc circuit bi-directionally modulates pain behaviors. Furthermore, circuit-specific molecular profiling and pharmacological studies revealed dopamine receptor 3 as a candidate target for pain modulation and non-opioid analgesic development. Taken together, these findings provide a previously unknown neural circuit for pain sensation and non-opioid analgesia and a valuable molecular target for developing future safer medication.

Corticotropin-releasing factor neurones in the paraventricular nucleus of the hypothalamus modulate isoflurane anaesthesia and its responses to acute stress in mice.

BACKGROUND: Corticotropin-releasing factor (CRF) neurones in the paraventricular nucleus (PVN) of the hypothalamus (PVNCRF neurones) can promote wakefulness and are activated under anaesthesia. However, whether these neurones contribute to anaesthetic effects is unknown. METHODS: With a combination of chemogenetic and molecular approaches, we examined the roles of PVNCRF neurones in isoflurane anaesthesia in mice and further explored the underlying cellular and molecular mechanisms. RESULTS: PVN neurones exhibited increased Fos expression during isoflurane anaesthesia (mean [standard deviation], 218 [69.3] vs 21.3 [7.3]; P<0.001), and ∼75% were PVNCRF neurones. Chemogenetic inhibition of PVNCRF neurones facilitated emergence from isoflurane anaesthesia (11.7 [1.1] vs 13.9 [1.2] min; P=0.001), whereas chemogenetic activation of these neurones delayed emergence from isoflurane anaesthesia (16.9 [1.2] vs 13.9 [1.3] min; P=0.002). Isoflurane exposure increased CRF protein expression in PVN (4.0 [0.1] vs 2.2 [0.3], respectively; P<0.001). Knockdown of CRF in PVNCRF neurones mimicked the effects of chemogenetic inhibition of PVNCRF neurones in facilitating emergence (9.6 [1.1] vs 13.0 [1.4] min; P=0.003) and also abolished the effects of chemogenetic activation of PVNCRF neurones on delaying emergence from isoflurane anaesthesia (10.3 [1.3] vs 16.0 [2.6] min; P<0.001). Acute, but not chronic, stress delayed emergence from isoflurane anaesthesia (15.5 [1.5] vs 13.0 [1.4] min; P=0.004). This effect was reversed by chemogenetic inhibition of PVNCRF neurones (11.7 [1.6] vs 14.7 [1.4] min; P=0.001) or knockdown of CRF in PVNCRF neurones (12.3 [1.5] vs 15.3 [1.6] min; P=0.002). CONCLUSIONS: CRF neurones in the PVN of the hypothalamus neurones modulate isoflurane anaesthesia and acute stress effects on anaesthesia through CRF signalling.

Low-dose naloxone for prophylaxis of sufentanil-induced choking and postoperative nausea and vomiting.

Sufentanil, a potent opioid, serves as the first option for perioperative analgesia owing to its analgesic effect, long duration and stable hemodynamics, whereas its side effects frequently blunt its application. The intravenous (IV) injection of sufentanil during anesthesia induction has high incidence of choking or bucking reaction, which is defined as sufentanil-induced cough (SIC). Moreover, postoperative nausea and vomiting (PONV) is a common and stressful complication, which is also related to the usage of opioid. High incidence of PONV is reported in the patients with SIC. Hence, we sought to determine whether naloxone, an opioid antagonist, at low dose would decrease the incidences of SIC and PONV. 216 female patients undergoing gynecological laparoscopic operation (<2 h) under general anesthesia were recruited in this study, and randomly assigned into two groups: Group N (patients receiving naloxone and Group C (patients receiving vehicle). Sufentanil (0.5 µg/kg within 5 s) was given in anesthesia induction, and low-dose naloxone (1.25 µg/kg) or identical vehicle was initially injected 5 min prior to induction, with the incidence and severity of SIC estimated. Subsequently, naloxone or vehicle was continuously infused at the rate of 0.5 µg/kg/h in the initiation of operation until the end of the operation, and the transverse abdominal fascia block (TAP) was performed for postoperative analgesia. The PONV profiles such as incidence and the severity, grading, and the frequencies of antiemetic usage within 24 h were evaluated, with VAS scores and remedial measures for analgesia during the first 24 h postoperatively were recorded. Our results revealed that one bolus of low-dose naloxone prior to the induction significantly mitigated the incidence of SIC, and intraoperative continuous infusion of low-dose naloxone reduced the incidence and the severity of PONV, so that the postoperative VAS scores and further remedial analgesia were not altered. These results not only provide clinical solutions for prophylaxis of SIC and PONV, but also suggests that opioids may act as a key role in both SIC and PONV, whereas opioid antagonist may hit two tasks with one stone. Moreover, further investigations are required to address the underlying mechanism of SIC and PONV. Clinical Trial Registration: [www.chictr.org.cn], identifier [ChiCTR2200064865].

Contralateral Projection of Anterior Cingulate Cortex Contributes to Mirror-Image Pain.

Long-term limb nerve injury often leads to mirror-image pain (MIP), an abnormal pain sensation in the limb contralateral to the injury. Although it is clear that MIP is mediated in part by central nociception processing, the underlying mechanisms remain poorly understood. The anterior cingulate cortex (ACC) is a key brain region that receives relayed peripheral nociceptive information from the contralateral limb. In this study, we induced MIP in male mice, in which a unilateral chronic constrictive injury of the sciatic nerve (CCI) induced a decreased nociceptive threshold in both hind limbs and an increased number of c-Fos-expressing neurons in the ACC both contralateral and ipsilateral to the injured limb. Using viral-mediated projection mapping, we observed that a portion of ACC neurons formed monosynaptic connections with contralateral ACC neurons. Furthermore, the number of cross-callosal projection ACC neurons that exhibited c-Fos signal was increased in MIP-expressing mice, suggesting enhanced transmission between ACC neurons of the two hemispheres. Moreover, selective inhibition of the cross-callosal projection ACC neurons contralateral to the injured limb normalized the nociceptive sensation of the uninjured limb without affecting the increased nociceptive sensation of the injured limb in CCI mice. In contrast, inhibition of the non-cross-callosal projection ACC neurons contralateral to the injury normalized the nociceptive sensation of the injured limb without affecting the MIP exhibited in the uninjured limb. These results reveal a circuit mechanism, namely, the cross-callosal projection of ACC between two hemispheres, that contributes to MIP and possibly other forms of contralateral migration of pain sensation.SIGNIFICANCE STATEMENT Mirror-image pain (MIP) refers to the increased pain sensitivity of the contralateral body part in patients with chronic pain. This pathology requires central processing, yet the mechanisms are less known. Here, we demonstrate that the cross-callosal projection neurons in the anterior cingulate cortex (ACC) contralateral to the injury contribute to MIP exhibited in the uninjured limb, but do not affect nociceptive sensation of the injured limb. In contrast, the non-cross-callosal projection neurons in the ACC contralateral to the injury contribute to nociceptive sensation of the injured limb, but do not affect MIP exhibited in the uninjured limb. Our study depicts a novel cross-callosal projection of ACC that contributes to MIP, providing a central mechanism for MIP in chronic pain state.

Association Between Burst-Suppression Latency and Burst-Suppression Ratio Under Isoflurane or Adjuvant Drugs With Isoflurane Anesthesia in Mice.

The same doses of anesthesia may yield varying depths of anesthesia in different patients. Clinical studies have revealed a possible causal relationship between deep anesthesia and negative short- and long-term patient outcomes. However, a reliable index and method of the clinical monitoring of deep anesthesia and detecting latency remain lacking. As burst-suppression is a characteristic phenomenon of deep anesthesia, the present study investigated the relationship between burst-suppression latency (BSL) and the subsequent burst-suppression ratio (BSR) to find an improved detection for the onset of intraoperative deep anesthesia. The mice were divided young, adult and old group treated with 1.0% or 1.5% isoflurane anesthesia alone for 2 h. In addition, the adult mice were pretreated with intraperitoneal injection of ketamine, dexmedetomidine, midazolam or propofol before they were anesthetized by 1.0% isoflurane for 2 h. Continuous frontal, parietal and occipital electroencephalogram (EEG) were acquired during anesthesia. The time from the onset of anesthesia to the first occurrence of burst-suppression was defined as BSL, while BSR was calculated as percentage of burst-suppression time that was spent in suppression periods. Under 1.0% isoflurane anesthesia, we found a negative correlation between BSL and BSR for EEG recordings obtained from the parietal lobes of young mice, from the parietal and occipital lobes of adult mice, and the occipital lobes of old mice. Under 1.5% isoflurane anesthesia, only the BSL calculated from EEG data obtained from the occipital lobe was negatively correlated with BSR in all mice. Furthermore, in adult mice receiving 1.0% isoflurane anesthesia, the co-administration of ketamine and midazolam, but not dexmedetomidine and propofol, significantly decreased BSL and increased BSR. Together, these data suggest that BSL can detect burst-suppression and predict the subsequent BSR under isoflurane anesthesia used alone or in combination with anesthetics or adjuvant drugs. Furthermore, the consistent negative correlation between BSL and BSR calculated from occipital EEG recordings recommends it as the optimal position for monitoring burst-suppression.

GABAergic Neurons in the Dorsal-Intermediate Lateral Septum Regulate Sleep-Wakefulness and Anesthesia in Mice.

BACKGROUND: The γ-aminobutyric acid-mediated (GABAergic) inhibitory system in the brain is critical for regulation of sleep-wake and general anesthesia. The lateral septum contains mainly GABAergic neurons, being cytoarchitectonically divided into the dorsal, intermediate, and ventral parts. This study hypothesized that GABAergic neurons of the lateral septum participate in the control of wakefulness and promote recovery from anesthesia. METHODS: By employing fiber photometry, chemogenetic and optogenetic neuronal manipulations, anterograde tracing, in vivo electrophysiology, and electroencephalogram/electromyography recordings in adult male mice, the authors measured the role of lateral septum GABAergic neurons to the control of sleep-wake transition and anesthesia emergence and the corresponding neuron circuits in arousal and emergence control. RESULTS: The GABAergic neurons of the lateral septum exhibited high activities during the awake state by in vivo fiber photometry recordings (awake vs. non-rapid eye movement sleep: 3.3 ± 1.4% vs. -1.3 ± 1.2%, P < 0.001, n = 7 mice/group; awake vs. anesthesia: 2.6 ± 1.2% vs. -1.3 ± 0.8%, P < 0.001, n = 7 mice/group). Using chemogenetic stimulation of lateral septum GABAergic neurons resulted in a 100.5% increase in wakefulness and a 51.2% reduction in non-rapid eye movement sleep. Optogenetic activation of these GABAergic neurons promoted wakefulness from sleep (median [25th, 75th percentiles]: 153.0 [115.9, 179.7] s to 4.0 [3.4, 4.6] s, P = 0.009, n = 5 mice/group) and accelerated emergence from isoflurane anesthesia (514.4 ± 122.2 s vs. 226.5 ± 53.3 s, P < 0.001, n = 8 mice/group). Furthermore, the authors demonstrated that the lateral septum GABAergic neurons send 70.7% (228 of 323 cells) of monosynaptic projections to the ventral tegmental area GABAergic neurons, preferentially inhibiting their activities and thus regulating wakefulness and isoflurane anesthesia depth. CONCLUSIONS: The results uncover a fundamental role of the lateral septum GABAergic neurons and their circuit in maintaining awake state and promoting general anesthesia emergence time.

KCNQ Channels in the Mesolimbic Reward Circuit Regulate Nociception in Chronic Pain in Mice.

Mesocorticolimbic dopaminergic (DA) neurons have been implicated in regulating nociception in chronic pain, yet the mechanisms are barely understood. Here, we found that chronic constructive injury (CCI) in mice increased the firing activity and decreased the KCNQ channel-mediated M-currents in ventral tegmental area (VTA) DA neurons projecting to the nucleus accumbens (NAc). Chemogenetic inhibition of the VTA-to-NAc DA neurons alleviated CCI-induced thermal nociception. Opposite changes in the firing activity and M-currents were recorded in VTA DA neurons projecting to the medial prefrontal cortex (mPFC) but did not affect nociception. In addition, intra-VTA injection of retigabine, a KCNQ opener, while reversing the changes of the VTA-to-NAc DA neurons, alleviated CCI-induced nociception, and this was abolished by injecting exogenous BDNF into the NAc. Taken together, these findings highlight a vital role of KCNQ channel-mediated modulation of mesolimbic DA activity in regulating thermal nociception in the chronic pain state.

Medial septum glutamatergic neurons control wakefulness through a septo-hypothalamic circuit.

The medial septum (MS) is involved in arousal-based behaviors and modulates general anesthesia response. However, the role of MS in wakefulness control remains unknown. Here, combining double fluorescence in situ hybridization and optrode recording, we showed that MS glutamatergic neurons exhibited higher activities preferentially during wakefulness. Activating these neurons, either optogenetically or chemogenetically, strongly promoted wakefulness, mainly through the transition from non-rapid eye movement (NREM) sleep to wakefulness. In contrast, inactivation of these neurons reduced wakefulness by the transition from wakefulness to NREM sleep. Furthermore, both rabies-mediated monosynaptic retrograde and anterograde tracing showed that MS glutamatergic neurons monosynaptically innervated lateral hypothalamus (LH) glutamatergic neurons, which were also wake-active as well as wake-promoting. Activating MS-derived glutamatergic terminals in LH enhanced wakefulness, whereas silencing MS glutamatergic neurons destabilized the wake-active preference of LH glutamatergic neurons. These results reveal a vital role of MS glutamatergic neurons in wakefulness control and depict a novel septo-hypothalamic circuit for wakefulness.

Cryopreservation of peripheral blood mononuclear cells using uncontrolled rate freezing.

Peripheral blood mononuclear cells are widely used as source material for anticancer immunotherapies. The conventional cryopreservation method for peripheral blood mononuclear cells is time-consuming and expansive, which involves controlled rate freezing followed by storage in liquid nitrogen. Instead, the convenient uncontrolled rate freezing cryopreservation method had been reported successfully in peripheral blood hematopoietic stem cells and peripheral blood progenitor cells. Therefore, we hypothesized that uncontrolled rate freezing cooling method maybe also applied to peripheral blood mononuclear cells cryopreservation. In this study, we evaluated the performance of uncontrolled rate freezing and controlled rate freezing cooling methods through cell recovery rate, viability, differentiation potential into cytokine-induced killer cells and the cellular properties of the cultured cytokine-induced killer cells. The results showed similar post-thaw viability and recovery rate in both controlled rate freezing and uncontrolled rate freezing cryopreserved peripheral blood mononuclear cells. Importantly, the uncontrolled rate freezing cryopreserved peripheral blood mononuclear cells exhibited higher growth ratio and earlier cell clustering during ex-vivo cytokine-induced killer cell culture than the controlled rate freezing ones. These two groups of expanded cytokine-induced killer cells also exhibited similar effector cell subset ratio and tumoricidal activity. In general, the performance of cryopreserved peripheral blood mononuclear cells using uncontrolled rate freezing cooling method, with the commercial cryoprotective agent CellBanker 2, was equal or better than the controlled rate freezing method. Our study implied that the combined use of cryoprotective agent CellBanker 2 and uncontrolled rate freezing could be a convenient cryopreservation method for peripheral blood mononuclear cells.

Mesocortical BDNF signaling mediates antidepressive-like effects of lithium.

Lithium has been used to treat major depressive disorder, yet the neural circuit mechanisms underlying this therapeutic effect remain unknown. Here, we demonstrated that the ventral tegmental area (VTA) dopamine (DA) neurons that project to the medial prefrontal cortex (mPFC), but not to nucleus accumbens (NAc), contributed to the antidepressive-like effects of lithium. Projection-specific electrophysiological recordings revealed that high concentrations of lithium increased firing rates in mPFC-, but not NAc-, projecting VTA DA neurons in mice treated with chronic unpredictable mild stress (CMS). In parallel, chronic administration of high-dose lithium in CMS mice restored the firing properties of mPFC-projecting DA neurons, and also rescued CMS-induced depressive-like behaviors. Nevertheless, chronic lithium treatment was insufficient to change the basal firing rates in NAc-projecting VTA DA neurons. Furthermore, chemogenetic activation of mPFC-, but not NAc-, projecting VTA DA neurons mimicked the antidepressive-like effects of lithium in CMS mice. Chemogenetic downregulation of VTA-mPFC DA neurons' firing activity abolished the antidepressive-like effects of lithium in CMS mice. Finally, we found that the antidepressant-like effects induced by high-dose lithium were mediated by BNDF signaling in the mesocortical DA circuit. Together, these results demonstrated the role of mesocortical DA projection in antidepressive-like effects of lithium and established a circuit foundation for lithium-based antidepressive treatment.

Chronic Pain Impairs Memory Formation via Disruption of Neurogenesis Mediated by Mesohippocampal Brain-Derived Neurotrophic Factor Signaling.

BACKGROUND: Chronic pain patients often complain of their poor memory. The mechanisms underlying chronic pain-related memory impairment remain elusive, and there are few clinical therapeutic strategies available for this condition. METHODS: In a neuropathic pain model induced by chronic constrictive injury of the sciatic nerve in male mice, we used circuit-specific electrophysiological recording, combined with chemogenetic, molecular, and pharmacologic methods, to examine the circuit and molecular mechanisms underlying chronic pain-related memory impairment. RESULTS: Our current results show that chronic neuropathic pain impaired the acquisition of spatial memory and, meanwhile, reduced adult neurogenesis in the dentate gyrus. Experimentally reducing dentate gyrus neurogenesis mimicked this pain-induced effect on spatial memory formation in naïve mice. Furthermore, pain-associated impairments of both hippocampal neurogenesis and memory formation were rescued or mimicked by chemogenetic activation or deactivation, respectively, of the ventral tegmental area dopaminergic projection, through which ventral tegmental area-released brain-derived neurotrophic factor was required. Importantly, we found that chronic, but not acute, systematic administration of subanesthetic doses of ketamine, while without relieving pain, ameliorated chronic pain-related impairment of spatial memory formation, potentially by rescuing brain-derived neurotrophic factor-mediated dentate gyrus neurogenesis. CONCLUSIONS: These findings provide a novel, circuit-based mechanistic link between chronic pain and memory formation deficit, and potential new therapeutic options for chronic pain-related learning deficit and memory impairment.

Recovery and functionality of cryopreserved peripheral blood mononuclear cells using five different xeno-free cryoprotective solutions.

In this study, we compared three commercially available and two widely used CPAs for their ability of cryopreserving PBMCs. Similar survival (81.0%) and recovery rate (73.7%) were observed among cells using these five CPAs. However, all the cryopreserved PBMCs exhibited a significantly lower survival rate when compared with the fresh samples (94.3%). We further evaluated effector cell subpopulation and tumoricidal activity of PBMC-derived cytokine-induced killing (CIK) cells and natural killing (NK) cells. Similar and high survival (CIK: 88.6%; NK: 87.5%) and recovery (CIK: 99.5%; NK: 99.7%) rates were detected in CIK and NK cells prepared from cryopreserved PBMCs using the five CPAs. The CD3+CD56+ effector percentage (27.3%) of cryopreserved PBMC-derived CIK cells using the five different CPAs and their tumoricidal activities on melanoma CHL-1 cells (45.7%) and bladder cancer cell line T-24 (44.7%) were similar but significantly lower than those of the fresh PBMC-derived controls (effector: 30.7%; CHL-1: 84.2%; T-24: 82.2%). Cryopreserved PBMC-derived NK cells also exhibited similar tumoricidal activities (CHL-1: 73.8%; T-24: 71.9%) but was significantly lower than that of the fresh control group. We were not able to identify a specific CPA that performed superior than others in PBMC cryopreservation.

Brain-derived neurotrophic factor-mediated projection-specific regulation of depressive-like and nociceptive behaviors in the mesolimbic reward circuitry.

Increasing evidence suggests that the mesolimbic reward system plays critical roles in the regulation of depression and nociception; however, its circuitry and cellular mechanisms remain unclear. In this study, we investigated the output-specific regulatory roles of dopaminergic (DA) neurons within the ventral tegmental area (VTA) in depressive-like and nociceptive behaviors in mice subjected to unpredictable chronic mild stress (CMS), using the projection-specific electrophysiological recording, pharmacological manipulation, behavioral test, and molecular biology technologies. We demonstrated that CMS decreased the firing activity in VTA projecting to medial prefrontal cortex (VTA → mPFC), but not in VTA to nucleus accumbens (VTA → NAc), DA neurons. However, both VTA → mPFC and VTA → NAc DA neurons showed increased firing activity in response to morphine perfusion in CMS mice. Behavioral results showed that intra-VTA microinjection of morphine (25.5 ng/0.15 µL) relieved depressive-like behaviors, intriguingly, accompanied by a thermal hyperalgesia. Furthermore, the relief of depressive-like behaviors induced by intra-VTA injection of morphine in CMS mice could be prevented by blocking brain-derived neurotrophic factor (BDNF) signaling and mimicked by the administration of exogenous BDNF in mPFC rather than in NAc shell. Nociceptive responses induced by the activation of VTA DA neurons with morphine in CMS mice could be prevented by blocking BDNF signaling or mimicked by administration of exogenous BDNF in NAc shell, but not in mPFC. These results reveal projection-specific regulatory mechanisms of depression and nociception in the mesolimbic reward circuitry and provide new insights into the neural circuits involved in the processing of depressive and nociceptive information.

Astroglial MicroRNA-219-5p in the Ventral Tegmental Area Regulates Nociception in Rats.

BACKGROUND: The authors previously reported that noncoding microRNA miR-219-5p is down-regulated in the spinal cord in a nociceptive state. The ventral tegmental area also plays critical roles in modulating nociception, although the underlying mechanism remains unknown. The authors hypothesized that miR-219-5p in the ventral tegmental area also may modulate nociception. METHODS: The authors studied the bidirectional regulatory role of ventral tegmental area miR-219-5p in a rat complete Freund's adjuvant model of inflammatory nociception by measuring paw withdrawal latencies. Using molecular biology technologies, the authors measured the effects of astroglial coiled-coil and C2 domain containing 1A/nuclear factor κB cascade and dopamine neuron activity on the down-regulation of ventral tegmental area miR-219-5p-induced nociceptive responses. RESULTS: MiR-219-5p expression in the ventral tegmental area was reduced in rats with thermal hyperalgesia. Viral overexpression of ventral tegmental area miR-219-5p attenuated complete Freund's adjuvant-induced nociception from 7 days after complete Freund's adjuvant injection (paw withdrawal latencies: 6.09 ± 0.83 s vs. 3.96 ± 0.76 s; n = 6/group). Down-regulation of ventral tegmental area miR-219-5p in naïve rats was sufficient to induce thermal hyperalgesia from 7 days after lentivirus injection (paw withdrawal latencies: 7.09 ± 1.54 s vs. 11.75 ± 2.15 s; n = 8/group), which was accompanied by increased glial fibrillary acidic protein (fold change: 2.81 ± 0.38; n = 3/group) and reversed by intraventral tegmental area injection of the astroglial inhibitor fluorocitrate. The nociceptive responses induced by astroglial miR-219-5p down-regulation were inhibited by interfering with astroglial coiled-coil and C2 domain containing 1A/nuclear factor-κB signaling. Finally, pharmacologic inhibition of ventral tegmental area dopamine neurons alleviated this hyperalgesia. CONCLUSIONS: Down-regulation of astroglial miR-219-5p in ventral tegmental area induced nociceptive responses are mediated by astroglial coiled-coil and C2 domain containing 1A/nuclear factor-κB signaling and elevated dopamine neuron activity.

Brain-Derived Neurotrophic Factor in the Mesolimbic Reward Circuitry Mediates Nociception in Chronic Neuropathic Pain.

BACKGROUND: The mesolimbic reward system plays a critical role in modulating nociception; however, its underlying molecular, cellular, and neural circuitry mechanisms remain unknown. METHODS: Chronic constrictive injury (CCI) of the sciatic nerve was used to model neuropathic pain. Projection-specific in vitro recordings in mouse brain slices and in vivo recordings from anesthetized animals were used to measure firing of dopaminergic neurons in the ventral tegmental area (VTA). The role of VTA-nucleus accumbens (NAc) circuitry in nociceptive regulation was assessed using optogenetic and pharmacological manipulations, and the underlying molecular mechanisms were investigated by Western blotting, enzyme-linked immunosorbent assays, and conditional knockdown techniques. RESULTS: c-Fos expression in and firing of contralateral VTA-NAc dopaminergic neurons were elevated in CCI mice, and optogenetic inhibition of these neurons reversed CCI-induced thermal hyperalgesia. CCI increased the expression of brain-derived neurotrophic factor (BDNF) protein but not messenger RNA in the contralateral NAc. This increase was reversed by pharmacological inhibition of VTA dopaminergic neuron activity, which induced an antinociceptive effect that was neutralized by injecting exogenous BDNF into the NAc. Moreover, inhibition of BDNF synthesis in the VTA with anisomycin or selective knockdown of BDNF in the VTA-NAc pathway was antinociceptive in CCI mice. CONCLUSIONS: These results reveal a novel mechanism of nociceptive modulation in the mesolimbic reward circuitry and provide new insight into the neural circuits involved in the processing of nociceptive information.