Mechanics of spindle orientation in human mitotic cells is determined by pulling forces on astral microtubules and clustering of cortical dynein.

The forces that orient the spindle in human cells remain poorly understood due to a lack of direct mechanical measurements in mammalian systems. We use magnetic tweezers to measure the force on human mitotic spindles. Combining the spindle's measured resistance to rotation, the speed at which it rotates after laser ablating astral microtubules, and estimates of the number of ablated microtubules reveals that each microtubule contacting the cell cortex is subject to ∼5 pN of pulling force, suggesting that each is pulled on by an individual dynein motor. We find that the concentration of dynein at the cell cortex and extent of dynein clustering are key determinants of the spindle's resistance to rotation, with little contribution from cytoplasmic viscosity, which we explain using a biophysically based mathematical model. This work reveals how pulling forces on astral microtubules determine the mechanics of spindle orientation and demonstrates the central role of cortical dynein clustering.

Lidocaine Spray for Acute Postsurgical Pain Control After Posterior Pharyngeal Flap Surgery.

OBJECTIVES: This study evaluated the use of lidocaine spray for acute postsurgical pain control after posterior pharyngeal flap surgery. METHODS: Fifty patients aged 4 to 14 years who were scheduled to undergo elective posterior pharyngeal flap surgery were randomized to receive 2.4% lidocaine spray (Group L) or an identical volume of placebo spray (Group C) on the surgical field at the end of the surgery. The primary outcome was the maximum postoperative pain score in the postanesthesia care unit. RESULTS: The maximum pain score in Group L was significantly lower than that in Group C (p = 0.001). The incidence of moderate-to-severe pain in the postanesthesia care unit was significantly lower in Group L than that in Group C (p < 0.001). In the postanesthesia care unit, more patients in Group C were prescribed rescue analgesics (p < 0.001). The time to the first rescue analgesic was also significantly shorter in Group L (p < 0.001). The incidence and maximum score of emergence agitation were lower in Group L than in Group C. Compared with Group C, Group L showed earlier postoperative fluid intake (p = 0.001). Moreover, the score for parental satisfaction with pain control was higher in Group L than in Group C (p < 0.001). CONCLUSIONS: Our findings indicated that the use of 2.4% lidocaine aerosol spray on the surgical site at the end of the surgery could produce good analgesia for acute postoperative pain, reduce the incidence and severity of EA, and shorten the time to restore fluid intake. LEVEL OF EVIDENCE: 2 Laryngoscope, 134:2438-2443, 2024.

Clustering of cortical dynein regulates the mechanics of spindle orientation in human mitotic cells.

The forces which orient the spindle in human cells remain poorly understood due to a lack of direct mechanical measurements in mammalian systems. We use magnetic tweezers to measure the force on human mitotic spindles. Combining the spindle's measured resistance to rotation, the speed it rotates after laser ablating astral microtubules, and estimates of the number of ablated microtubules reveals that each microtubule contacting the cell cortex is subject to ~1 pN of pulling force, suggesting that each is pulled on by an individual dynein motor. We find that the concentration of dynein at the cell cortex and extent of dynein clustering are key determinants of the spindle's resistance to rotation, with little contribution from cytoplasmic viscosity, which we explain using a biophysically based mathematical model. This work reveals how pulling forces on astral microtubules determine the mechanics of spindle orientation and demonstrates the central role of cortical dynein clustering.

Determination of the ED90 of Dexmedetomidine Infusion to Prevent Emergence Agitation in Children Undergoing Dental Rehabilitation With Sevoflurane Anesthesia: A Biased-Coin Up-and-Down Sequential Allocation Trial.

BACKGROUND: Emergence agitation (EA) is an adverse complication during early recovery from sevoflurane anesthesia. Continuous intravenous infusion of dexmedetomidine (DEX) is commonly used for EA prevention. However, a wide dose range is used for preventing EA, and the optimal dose remains unknown. This study was aimed at determining the optimal dose (the 90% effective dose [ED90]) of DEX for continuous intraoperative infusion for EA prevention in children. METHODS: We enrolled children aged 3 to 7 years who underwent dental treatment under sevoflurane anesthesia. DEX was continuously infused from the time of the establishment of the intravenous access until 5 minutes before the end of surgery. The initial DEX dose was 0.5 µg/kg/h, and subsequent dose adjustments were determined based on the response of the previous patient by using an up-down sequential allocation with a biased-coin design. The primary outcome was the ED90 for continuous DEX infusion based on the success or failure of the EA-preventing dose. RESULTS: Forty-five patients were enrolled in the study. The DEX dose ranged from 0.50 to 0.90 µg/kg/h. The estimated ED90 (95% confidence interval [CI]) for preventing EA was 0.74 µg/kg/h (0.67-1.05 µg/kg/h). The duration of surgery (mean ± standard deviation [SD]) was 113 ± 30 minutes. The times (mean ± SD) for extubation, time to emergence, and recovery time were 5 ± 2 minutes, 27 ± 9 minutes, and 39 ± 7 minutes, respectively. CONCLUSIONS: The ED90 for continuous intraoperative DEX infusion for EA prevention in pediatric patients receiving dental treatment under sevoflurane anesthesia was 0.74 µg/kg/h (95% CI, 0.67-1.05 µg/kg/h).

Glutamate-releasing BEST1 channel is a new target for neuroprotection against ischemic stroke with wide time window.

Many efforts have been made to understand excitotoxicity and develop neuroprotectants for the therapy of ischemic stroke. The narrow treatment time window is still to be solved. Given that the ischemic core expanded over days, treatment with an extended time window is anticipated. Bestrophin 1 (BEST1) belongs to a bestrophin family of calcium-activated chloride channels. We revealed an increase in neuronal BEST1 expression and function within the peri-infarct from 8 to 48 h after ischemic stroke in mice. Interfering the protein expression or inhibiting the channel function of BEST1 by genetic manipulation displayed neuroprotective effects and improved motor functional deficits. Using electrophysiological recordings, we demonstrated that extrasynaptic glutamate release through BEST1 channel resulted in delayed excitotoxicity. Finally, we confirmed the therapeutic efficacy of pharmacological inhibition of BEST1 during 6-72 h post-ischemia in rodents. This delayed treatment prevented the expansion of infarct volume and the exacerbation of neurological functions. Our study identifies the glutamate-releasing BEST1 channel as a potential therapeutic target against ischemic stroke with a wide time window.

Functional reconstruction of the impaired cortex and motor function by hMGEOs transplantation in stroke.

Stroke is the leading cause of death and long-term disability worldwide. But treatments are not available to promote functional recovery, and efficient therapies need to be investigated. Stem cell-based therapies hold great promise as potential technologies to restore function in brain disorders. Loss of GABAergic interneurons after stroke may result in sensorimotor defects. Here, by transplanting human brain organoids resembling the MGE domain (human MGE organoids, hMGEOs) derived from human induced pluripotent stem cells (hiPSCs) into the infarcted cortex of stroke mice, we found that grafted hMGEOs survived well and primarily differentiated into GABAergic interneurons and significantly restored the sensorimotor deficits of stroke mice for a long time. Our study offers the feasibility of stem cell replacement therapeutics strategy for stroke.

Cerebral organoids transplantation repairs infarcted cortex and restores impaired function after stroke.

Stroke usually causes prolonged or lifelong disability, owing to the permanent loss of infarcted tissue. Although a variety of stem cell transplantation has been explored to improve neuronal defect behavior by enhancing neuroplasticity, it remains unknown whether the infarcted tissue can be reconstructed. We here cultured human cerebral organoids derived from human pluripotent stem cells (hPSCs) and transplanted them into the junction of the infarct core and the peri-infarct zone of NOD-SCID mice subjected to stroke. Months later, we found that the grafted organoids survived well in the infarcted core, differentiated into target neurons, repaired infarcted tissue, sent axons to distant brain targets, and integrated into the host neural circuit and thereby eliminated sensorimotor defect behaviors of stroke mice, whereas transplantation of dissociated single cells from organoids failed to repair the infarcted tissue. Our study offers a new strategy for reconstructing infarcted tissue via organoids transplantation thereby reversing stroke-induced disability.

Preclinical evaluation of ZL006-05, a new antistroke drug with fast-onset antidepressant and anxiolytic effects.

BACKGROUND: Poststroke depression and anxiety, independent predictor of poor functional outcomes, are common in the acute phase of stroke. Up to now, there is no fast-onset antidepressive and anxiolytic agents suitable for the management of acute stroke. ZL006-05, a dual-target analgesic we developed, dissociates nitric oxide synthase from postsynaptic density-95 while potentiates α2-containing γ-aminobutyric acid type A receptor. This study aims to determine whether ZL006-05 can be used as an antistroke agent with fast-onset antidepressant and anxiolytic effects. METHODS: Photothrombotic stroke and transient middle cerebral artery occlusion were induced in rats and mice. Infarct size was measured by TTC(2,3,5-Triphenyltetrazolium chloride) staining or Nissl staining. Neurological defects were assessed by four-point scale neurological score or modified Neurological Severity Scores. Grid-walking, cylinder and modified adhesive removal tasks were conducted to assess sensorimotor functions. Spatial learning was assessed using Morris water maze task. Depression and anxiety were induced by unpredictable chronic mild stress. Depressive behaviours were assessed by tail suspension, forced swim and sucrose preference tests. Anxiety behaviours were assessed by novelty-suppressed feeding and elevated plus maze tests. Pharmacokinetics, toxicokinetics and long-term toxicity studies were performed in rats. RESULTS: Administration of ZL006-05 in the acute phase of stroke attenuated transient and permanent ischaemic injury and ameliorated long-term functional impairments significantly, with a treatment window of 12 hours after ischemia, and reduced plasminogen activato-induced haemorrhagic transformation. ZL006-05 produced fast-onset antidepressant and anxiolytic effects with onset latency of 1 hour in the normal and CMS mice, had antidepressant and anxiolytic effects in stroke mice. ZL006-05 crossed the blood-brain barrier and distributed into the brain rapidly, and had a high safety profile in toxicokinetics and long-term toxicological studies. CONCLUSION: ZL006-05 is a new neuroprotectant with fast-onset antidepressant and anxiolytic effects and has translational properties in terms of efficacy, safety and targeting of clinical issues.

Nos1+ and Nos1- excitatory neurons in the BLA regulate anxiety- and depression-related behaviors oppositely.

BACKGROUND: The basolateral amygdala (BLA) neurons are primarily glutamatergic and have been associated with emotion regulation. However, little is known about the roles of BLA neurons expressing neuronal nitric oxide synthase (nNOS, Nos1) in the regulation of emotional behaviors. METHODS: Using Nos1-cre mice and chemogenetic and optogenetic manipulations, we specifically silenced or activated Nos1+ or Nos1- neurons in the BLA, or silenced their projections to the anterdorsal bed nucleus of the stria terminalis (adBNST) and ventral hippocampus (vHPC). We measured anxiety behaviors in elevated plus maze (EPM) and open-field test (OFT), and measured depression behaviors in forced swimming test (FST) and tail suspension test (TST). RESULTS: BLA Nos1+ neurons were predominantly glutamatergic, and glutamatergic but not GABAergic Nos1+ neurons were involved in controlling anxiety- and depression-related behaviors. Interestingly, by selectively manipulating the activities of BLA Nos1+ and Nos1- excitatory neurons, we found that they had opposing effects on anxiety- and depression-related behaviors. BLA Nos1+ excitatory neurons projected to the adBNST, this BLA-adBNST circuit controlled the expression of anxiety- and depression-related behaviors, while BLA Nos1- excitatory neurons projected to vHPC, this BLA-vHPC circuit contributed to the expression of anxiety- and depression-related behaviors. Moreover, excitatory vHPC-adBNST circuit antagonized the role of BLA-adBNST circuit in regulating anxiety- and depression-related behaviors. CONCLUSIONS: BLA Nos1+ and Nos1- excitatory neuron subpopulations exert different effects on anxiety- and depression-related behaviors through distinct projection circuits, providing a new insight of BLA excitatory neurons in emotional regulation. LIMITATIONS: We did not perform retrograde labeling from adBNST and vHPC regions.

Ketone bodies promote stroke recovery via GAT-1-dependent cortical network remodeling.

Stroke is a leading cause of adult disability worldwide, and better drugs are needed to promote functional recovery after stroke. Growing evidence suggests the critical role of network excitability during the repair phase for stroke recovery. Here, we show that ß-hydroxybutyrate (ß-HB), an essential ketone body (KB) component, is positively correlated with improved outcomes in patients with stroke and promotes functional recovery in rodents with stroke during the repair phase. These beneficial effects of ß-HB depend on HDAC2/HDAC3-GABA transporter 1 (GAT-1) signaling-mediated enhancement of excitability and phasic GABA inhibition in the peri-infarct cortex and structural and functional plasticity in the ipsilateral cortex, the contralateral cortex, and the corticospinal tract. Together with available clinical approaches to elevate KB levels, our results offer a clinically translatable means to promote stroke recovery. Furthermore, GAT-1 can serve as a pharmacological target for developing drugs to promote functional recovery after stroke.

Enhanced AMPAR-dependent synaptic transmission by S-nitrosylation in the vmPFC contributes to chronic inflammatory pain-induced persistent anxiety in mice.

Chronic pain patients often have anxiety disorders, and some of them suffer from anxiety even after analgesic administration. In this study, we investigated the role of AMPAR-mediated synaptic transmission in the ventromedial prefrontal cortex (vmPFC) in chronic pain-induced persistent anxiety in mice and explored potential drug targets. Chronic inflammatory pain was induced in mice by bilateral injection of complete Freund's adjuvant (CFA) into the planta of the hind paws; anxiety-like behaviours were assessed with behavioural tests; S-nitrosylation and AMPAR-mediated synaptic transmission were examined using biochemical assays and electrophysiological recordings, respectively. We found that CFA induced persistent upregulation of AMPAR membrane expression and function in the vmPFC of anxious mice but not in the vmPFC of non-anxious mice. The anxious mice exhibited higher S-nitrosylation of stargazin (an AMPAR-interacting protein) in the vmPFC. Inhibition of S-nitrosylation by bilaterally infusing an exogenous stargazin (C302S) mutant into the vmPFC rescued the surface expression of GluA1 and AMPAR-mediated synaptic transmission as well as the anxiety-like behaviours in CFA-injected mice, even after ibuprofen treatment. Moreover, administration of ZL006, a small molecular inhibitor disrupting the interaction of nNOS and PSD-95 (20 mg·kg-1·d-1, for 5 days, i.p.), significantly reduced nitric oxide production and S-nitrosylation of AMPAR-interacting proteins in the vmPFC, resulting in anxiolytic-like effects in anxious mice after ibuprofen treatment. We conclude that S-nitrosylation is necessary for AMPAR trafficking and function in the vmPFC under chronic inflammatory pain-induced persistent anxiety conditions, and nNOS-PSD-95 inhibitors could be potential anxiolytics specific for chronic inflammatory pain-induced persistent anxiety after analgesic treatment.

Impact of choice of nostril on nasotracheal intubation when using video rigid stylet: a randomized clinical trial.

BACKGROUND: Patients undergoing oral and maxillofacial surgeries under general anesthesia usually require nasotracheal intubation. When presented with patients with equally patent nostrils, selection of the nostril to use for intubation is an important decision for facilitating intubation. The objective of this trial is to determine whether choice of nostril impacts nasotracheal intubation when using a video rigid stylet in patients undergoing oral and maxillofacial surgery. METHODS: Fifty patients scheduled for elective oral and maxillofacial surgery requiring nasotracheal intubation were randomly allocated into two groups to undergo nasotracheal intubation through the left nostril (Group L, n = 25) or the right nostril (Group R, n = 25). Intubation was performed by experienced anesthesiologists using a video rigid stylet. The primary endpoint was time to successful intubation, which was defined as the duration from when the tip of the stylet-tube assembly entered the selected nostril to when the tube entered the trachea. Secondary outcomes included: length of time for device insertion; length of time for tube insertion; total success rate; first-attempt success rate; number of intubation attempts; requirement of airway assisted maneuvers; incidence and severity of epistaxis. Intubation-related adverse events were monitored for up to postoperative 24 h. RESULTS: Median time (interquartile range) to tracheal intubation was 25.3 seconds (20.7 to 27.6) in Group L and 26.8 seconds (22.5 to 30.0) in Group R (median difference (MD) = 1.9; 95% confidence interval (CI) -1.8 to 5.7, P = 0.248). Nasotracheal intubation was successful in all patients in both groups and the first-attempt success rates in both groups were similar (Group L: 96% (24/25); Group R: 96% (24/25); relative risk (RR) 1.0; 95% CI 0.9 to 1.1; P > 0.999). No significant difference of requirement of assisted maneuvers was noted between the two groups (Group L: 36% (9/25); Group R: 28% (7/25); RR 0.8; 95% CI 0.3-1.8; P = 0.544). Furthermore, all patients showed a high quality of visualization of the glottis (Cormack and Lehane Grade I). For safety outcomes, the incidence and severity of epistaxis during intubation was comparable between the two groups. There were no significant differences between the selection of nostrils and intubation-related adverse events up to 24 h after surgery. CONCLUSIONS: When considering which nostril to use for intubation with video rigid stylet, either nostril can be used similarly. TRIAL REGISTRATION: Clinicaltrials.gov . Identifier: NCT05218590.

Self-organization of kinetochore-fibers in human mitotic spindles.

During eukaryotic cell division, chromosomes are linked to microtubules (MTs) in the spindle by a macromolecular complex called the kinetochore. The bound kinetochore microtubules (KMTs) are crucial to ensuring accurate chromosome segregation. Recent reconstructions by electron tomography (Kiewisz et al., 2022) captured the positions and configurations of every MT in human mitotic spindles, revealing that roughly half the KMTs in these spindles do not reach the pole. Here, we investigate the processes that give rise to this distribution of KMTs using a combination of analysis of large-scale electron tomography, photoconversion experiments, quantitative polarized light microscopy, and biophysical modeling. Our results indicate that in metaphase, KMTs grow away from the kinetochores along well-defined trajectories, with the speed of the KMT minus ends continually decreasing as the minus ends approach the pole, implying that longer KMTs grow more slowly than shorter KMTs. The locations of KMT minus ends, and the turnover and movements of tubulin in KMTs, are consistent with models in which KMTs predominately nucleate de novo at kinetochores in metaphase and are inconsistent with substantial numbers of non-KMTs being recruited to the kinetochore in metaphase. Taken together, this work leads to a mathematical model of the self-organization of kinetochore-fibers in human mitotic spindles.

Prenatal Isoflurane Exposure Induces Developmental Neurotoxicity in Rats: the Role of Gut Microbiota.

Fetal exposure to inhaled anesthetics, such as isoflurane, may lead to neurodevelopmental impairment in offspring. Yet, the mechanisms of prenatal isoflurane-induced developmental neurotoxicity have not been fully elucidated. Gut microbiota is a pivotal modulator of brain development and functions. While the antibiotic effect of isoflurane has been previously investigated, the relationship between prenatal isoflurane exposure and postnatal gut microbiota, brain biology, and behavior remains unknown. In the present study, we treated pregnant rats with 2% isoflurane for 4 h on gestational day 14. Their offspring were tested with novel object recognition task on postnatal day 28 (P28) to assess cognition. Fecal microbiome was assessed using 16S RNA sequencing. We also analyzed hippocampal expression of brain-derived neurotrophic factor (BDNF) in P28 rat brains. To further explore the role of gut microbiota on prenatal isoflurane-induced developmental neurotoxicity, we treated rats with mixed probiotics on P14 for 14 days and evaluated novel object recognition and hippocampal expression of BDNF on P28. Results indicate that prenatal exposure to isoflurane significantly decreased novel object recognition (novel object preference ratio: mean difference (MD) - 0.157; 95% confidence interval (CI) - 0.234 to - 0.080, P < 0.001) paralleled by diminished expression of hippocampal BDNF in juvenile rats. Prenatal exposure to isoflurane also significantly altered the diversity and composition of gut microbiota. Treatment with probiotics mitigated these changes in cognition (novel object preference ratio: isoflurane group vs. control group: MD - 0.177; 95% CI - 0.307 to - 0.047, P = 0.006; probiotic group vs. isoflurane group: MD 0.140; 95% CI 0.004 to 0.275, P = 0.042) and BDNF expression. Taken together, our findings suggest that gut dysbiosis may be involved in the pathogenesis of maternal isoflurane exposure-induced postnatal cognitive impairment. To determine the causal relationship between gut microbiota and cognition in prenatal anesthetic-induced developmental neurotoxicity, further studies are needed.

Disrupting the Interaction of nNOS with CAPON Prevents the Reinstatement of Morphine Conditioned Place Preference.

Drug abuse is a dramatic challenge for the whole society because of high relapse rate. Environmental cues are crucial for the preference memory of drug abuse. Extinction therapy has been developed to inhibit the motivational effect of drug cues to prevent the reinstatement of morphine abuse. However, extinction therapy alone only forms a new kind of unstable inhibitory memory. We found that morphine conditioned place preference (CPP) extinction training increased the association of nitric oxide synthase (nNOS) with its carboxy-terminal PDZ ligand (CAPON) in the dorsal hippocampus (dHPC) significantly and blocking the morphine-induced nNOS-CAPON association using Tat-CAPON-12C during and after extinction training reversed morphine-induced hippocampal neuroplasticity defect and prevented the reinstatement and spontaneous recovery of morphine CPP. Moreover, in the hippocampal selective ERK2 knock-out or nNOS knockout mice, the effect of Tat-CAPON-12C on the reinstatement of morphine CPP and hippocampal neuroplasticity disappeared, suggesting ERK2 is necessary for the effects of Tat-CAPON-12C. Together, our findings suggest that nNOS-CAPON interaction in the dHPC may affect the consolidation of morphine CPP extinction and dissociating nNOS-CAPON prevents the reinstatement and spontaneous recovery of morphine CPP, possibly through ERK2-mediated neuroplasticity and extinction memory consolidation, offering a new target to prevent the reinstatement of drug abuse.

Prevention of the return of extinguished fear by disrupting the interaction of neuronal nitric oxide synthase with its carboxy-terminal PDZ ligand.

Exposure therapy based on the extinction of fear memory is first-line treatment for post-traumatic stress disorder (PTSD). However, fear extinction is relatively easy to learn but difficult to remember, extinguished fear often relapses under a number of circumstances. Here, we report that extinction learning-induced association of neuronal nitric oxide synthase (nNOS) with its carboxy-terminal PDZ ligand (CAPON) in the infralimbic (IL) subregion of medial prefrontal cortex negatively regulates extinction memory and dissociating nNOS-CAPON can prevent the return of extinguished fear in mice. Extinction training significantly increases nNOS-CAPON association in the IL. Disruptors of nNOS-CAPON increase extracellular signal-regulated kinase (ERK) phosphorylation and facilitate the retention of extinction memory in an ERK2-dependent manner. More importantly, dissociating nNOS-CAPON after extinction training enhances long-term potentiation and excitatory synaptic transmission, increases spine density in the IL, and prevents spontaneous recovery, renewal and reinstatement of remote fear of mice. Moreover, nNOS-CAPON disruptors do not affect other types of learning. Thus, nNOS-CAPON can serve as a new target for treating PTSD.

A pain killer without analgesic tolerance designed by co-targeting PSD-95-nNOS interaction and α2-containning GABAARs.

Overactivation of N-methyl-D-aspartate receptor (NMDAR) in the spinal cord dorsal horn (SDH) in the setting of injury represents a key mechanism of neuropathic pain. However, directly blocking NMDAR or its downstream signaling, interaction between postsynaptic density-95 (PSD-95) and neuronal nitric oxide synthase (nNOS), causes analgesic tolerance, mainly due to GABAergic disinhibition. The aim of this study is to explore the possibility of preventing analgesic tolerance through co-targeting NMDAR downstream signaling and γ-aminobutyric acid type A receptors (GABAARs). Methods: Mechanical/thermal hyperalgesia were quantified to assess analgesic effects. Miniature postsynaptic currents were tested by patch-clamp recording to evaluate synaptic transmission in the SDH. GABA-evoked currents were tested on HEK293 cells expressing different subtypes of recombinant GABAARs to assess the selectivity of (+)-borneol and ZL006-05. The expression of α2 and α3 subunits of GABAARs and BDNF, and nNOS-PSD-95 complex levels were analyzed by western blotting and coimmunoprecipitation respectively. Open field test, rotarod test and Morris water maze task were conducted to evaluate the side-effect of ZL006-05. Results: (+)-Borneol selectively potentiated α2- and α3-containing GABAARs and prevented the disinhibition of laminae I excitatory neurons in the SDH and analgesic tolerance caused by chronic use of ZL006, a nNOS-PSD-95 blocker. A dual-target compound ZL006-05 produced by linking ZL006 and (+)-borneol through an ester bond blocked nNOS-PSD-95 interaction and potentiated α2-containing GABAAR selectively. Chronic use of ZL006-05 did not produce analgesic tolerance and unwanted side effects. Conclusion: By targeting nNOS-PSD-95 interaction and α2-containing GABAAR simultaneously, chronic use of ZL006-05 can avoid analgesic tolerance and unwanted side effects. Therefore, we offer a novel candidate drug without analgesic tolerance for treating neuropathic pain.

Environmental enrichment implies GAT-1 as a potential therapeutic target for stroke recovery.

Rationale: Stroke is a leading cause of adult disability worldwide, but no drug provides functional recovery during the repair phase. Accumulating evidence demonstrates that environmental enrichment (EE) promotes stroke recovery by enhancing network excitability. However, the complexities of utilizing EE in a clinical setting limit its translation. Methods: We used multifaceted approaches combining electrophysiology, chemogenetics, optogenetics, and floxed mice in a mouse photothrombotic stroke model to reveal the key target of EE-mediated stroke recovery. Results: EE reduced tonic gamma-aminobutyric acid (GABA) inhibition and facilitated phasic GABA inhibition in the peri-infarct cortex, thereby promoting network excitability and stroke recovery. These beneficial effects depended on GAT-1, a GABA transporter regulating both tonic and phasic GABA signaling, as EE positively regulated GAT-1 expression, trafficking, and function. Furthermore, GAT-1 was necessary for EE-induced network plasticity, including structural neuroplasticity, input synaptic strengthening in the peri-infarct cortex, output synaptic strengthening in the corticospinal tract, and sprouting of uninjured corticospinal axons across the midline into the territory of denervated spinal cord, and functional recovery from stroke. Moreover, restoration of GAT-1 function in the peri-infarct cortex by its overexpression showed similar beneficial effects on stroke recovery as EE exposure. Conclusion: GAT-1 is a key molecular substrate of the effects of EE on network excitability and consequent stroke recovery and can serve as a novel therapeutic target for stroke treatment during the repair phase.

Neuronal Nitric Oxide Synthase in Nucleus Accumbens Specifically Mediates Susceptibility to Social Defeat Stress through Cyclin-Dependent Kinase 5.

Stress-induced depression is common worldwide. NAc, a "reward" center, is recently reported to be critical to confer the susceptibility to chronic social defeat stress (CSDS) and the depression-related outcome. However, the underlying molecular mechanisms have not been well characterized. In this study, we induced depression-like behaviors with CSDS and chronic mild stress in male mice to mimic social and environmental factors, respectively, and observed animal behaviors with social interaction test, tail suspension test, and sucrose preference test. To determine the role of neuronal nitric oxide synthase (nNOS) and its product nitric oxide (NO), we used brain region-specifically nNOS overexpression and stereotaxic injection of NO inhibitor or donor. Moreover, the downstream molecular cyclin-dependent kinase 5 (CDK5) was explored by conditional KO and gene mutation. We demonstrate that nNOS-implicated mechanisms in NAc shell (NAcSh), including increased cell number, increased protein expression levels, and increased specific enzyme activity, contribute the susceptibility to social defeat and the following depression-like behaviors. NAcSh nNOS does not directly respond to chronic mild stress but facilitates the depression-like behaviors. The increased NAcSh nNOS expression after CSDS leads to the social avoidance and depression-like behaviors in defeated mice, which is dependent on the nNOS enzyme activity and NO production. Moreover, we identify the downstream signal in NAcSh. S-nitrosylation of CDK5 by NO contributes to enhanced CDK5 activity, leading to depression-related behaviors in susceptible mice. Therefore, NAcSh nNOS mediates susceptibility to social defeat stress and the depression-like behaviors through CDK5.SIGNIFICANCE STATEMENT Stress-induced depression is common worldwide, and chronic exposure to social and psychological stressors is important cause of human depression. Our study conducted with chronic social defeat stress mice models demonstrates that nNOS in NAcSh is crucial to regulate the susceptibility to social defeat stress and the following depression-like behaviors, indicating NAcSh nNOS as the responding molecule to social factors of depression. Moreover, we discover the downstream mechanism of NAcSh nNOS in mediating the susceptibility is NO and S-nitrosylation of CDK5. Thus, NAcSh nNOS mediates susceptibility to social defeat stress through CDK5 is a potential mechanism for depression, which may interpret how the brain transduces social stress exposure into depression.

Shikani Optical Stylet for Awake Nasal Intubation in Patients Undergoing Head and Neck Surgery.

OBJECTIVES: To evaluate the efficacy and safety of the Shikani optical stylet (SOS) versus fiberoptic bronchoscope (FOB) for awake nasal intubation in head and neck surgery patients with an anticipated difficult airway. STUDY DESIGN: Prospective randomized clinical trial. METHODS: This study involved 50 adult patients scheduled for elective head and neck surgery and presented with an anticipated difficult airway. Patients planned for awake nasotracheal intubation were randomly divided into two groups: FOB (n = 25) and SOS (n = 25). Patients were intubated under local anesthesia and sedation using the randomly assigned intubation device by anesthetists proficient in both airway devices. The time to successful intubation was regarded as the primary endpoint. RESULTS: The median time (interquartile range) to tracheal intubation in the FOB group was 74 seconds (57-108) and 38 seconds (27-60) in the SOS group (P < .001). Intubation success rates on the first attempt in the FOB and SOS groups were 96% and 92%, respectively (P > .999). Airway assisted maneuvers were required in six (24%) SOS intubations compared to 21 (84%) FOB intubations (P < .001). There were no significant differences between the groups in the incidences of oxygen desaturation and postoperative complications related to intubation. CONCLUSION: Compared to the FOB group, awake nasal intubation in the SOS group required significantly less time and fewer airway-assisted maneuvers on adult head and neck surgery patients with anticipated difficult airway. LEVEL OF EVIDENCE: 2 Laryngoscope, 131:319-325, 2021.