[The roles of glutamate in sleep and wakefulness].

Glutamate as an excitatory neurotransmitter in the central nervous system, participate in initiation and maintaining of sleep and wakefulness. The paper presents an overview of the research progress of glutamate in the regulation of sleep and wakefulness, especially focuses on its role in the brainstem, lateral hypothalamus and basal forebrain. Glutamate in the brain stem regulates the brain activity and maintains muscle tone during the wakefulness, as well as adjusts the electroencephalograph (EEG) in rapid eye movement phase and leads to muscle weakness. Glutamate in the lateral hypothalamus participates in the lateral hypothalamic arousal system by activating orexins neurons. The basal forebrain glutamatergic neurons take part in EEG synchronization and cause the decrease of sleep. Finally,The glutamatergic neurons of the cerebral cortex is not just a target of the arousal system, but itself contribute to regulation of arousal. Meantime, the glutamatergic neurons can regulate sleep stages through interaction with other types of neurons, which forms a complex sleep-wake regulation network in the brain. These indicate that the switches between different phases of sleep and wakefulness have different neuronal circuits.So we also reviewed the neuronal circuits and mechanisms that glutamate may be involved in. This review will help us to get a better understanding of the roles of glutamate in sleep and wakefulness.

A Giant Silence - An atypical association of sensorineural hearing loss with Giant Cell Arteritis.

Giant cell arteritis (GCA) is a chronic vasculitic disorder predominantly affecting medium to large sized arteries, prevalent in the 50 plus age group. This case illustrates an atypical presentation of this disease in the form of bilateral sensorineural hearing loss (SNHL). Apart from the presence of constitutional and vertiginous symptoms, there were essentially no classical features of GCA. Differentials were broad including infection, malignancy and medication toxicity as well as brain, eye and ear syndromes such as Cogan's syndrome, all of which were eventually excluded. Her diagnosis was ultimately confirmed on positron emission tomography, which highlights the diagnostic importance of this modality. She was managed with corticosteroids then tocilizumab and is making a gradual recovery. Literature review demonstrates that SNHL is more prevalent than previously suggested in GCA, although this does not have widespread recognition. Mechanisms of SNHL in GCA include vascular occlusion, immunological mechanisms including cross reactivity with viral antigens and direct viral infection. SNHL does appear to improve with corticosteroids. This case emphasizes the importance of considering GCA as an important differential in SNHL.

[Treatment of ankylosing spondylitis with thoracolumbar fractures by robot-assisted internal fixation in lateral decubitus position].

OBJECTIVE: To explore the effect of robot-assisted internal fixation in lateral decubitus position for the treatment of ankylosing spondylitis (AS) complicated with thoracolumbar fractures. METHODS: The clinical data of 26 patients with ankylosing spondylitis complicated with thoracolumbar fractures treated from January 2018 to June 2020 was retrospectively analyzed. According to different surgical methods, these patients were divided into observation group and control group. There were 8 patients in observation group, which were treated with robot-assisted percutaneous screw fixation in lateral decubitus position, including 4 males and 4 females, aged form 55 to 85 years old with an mean of (66.25±9.42) years, the course of disease was (4.00±0.76) days on average, 2 cases were T11 fracture, 2 cases were T12, 3 cases were L1 and 1 case was L2. And there were 18 patients in control group, which were treated with conventional percutaneous screw fixation in prone position, including 6 males and 12 females, aged from 48 to 81 years old with a mean of (61.22±9.53) years, the course of disease was (4.11±0.83) days on average, 2 cases were T10 injury, 3 cases were T11, 4 cases were T12, 7 cases were L1, and 2 cases were L2. The intraoperative blood loss, operation time, position time and postoperative neurological complications were compared between two groups. Postoperative visual analogue scale (VAS) at 1d and 3 months, and Oswestry Disability Index (ODI) before and 3 months after operation were observed. According to Gertzbein-Robbins standard to evaluate the accuracy of pedicle screw placement. RESULTS: There was no nerve injury due to pedicle screw placement in both groups. The intraoperative blood loss in observation group and control group was (34.13±4.61) ml and (78.17±22.02) ml, operation time was(92.13±9.82) min and (106.22±11.55) min, position time was(10.00±2.14) min and (15.17±2.66) min, the differences was statistically significant(P<0.05);VAS of the two groups were (2.38±0.52) points and (4.56±0.98) points one day after surgery, respectively, with statistically significant differences (P<0.05), while VAS and ODI three months after surgery showed no statistically significant differences (P>0.05). The screw accuracy was 96.88%(62/64) in observation group and 81.48%(88/108) in control group, the difference was statistically significant(P<0.05). CONCLUSION: Robot-assisted internal fixation in lateral decubitus position for the treatment of ankylosing spondylitis complicated with thoracolumbar fractures can shorten the position time and operation time, significantly improve the accuracy of internal fixation screw placement, relieve the early postoperative pain, reduce intraoperative blood loss and postoperative complications, and facilitate the fast track rehabilitation of patients.

[Study on elemental speciation analysis and transference characteristics of Arnebia euthroma (Royle) Johnst by ICP-MS].

The elemental transference characteristics and primary speciation analysis of Arnebia euthroma (Royle) Johnst were investigated in the present paper. The results showed: sealed digestion at high temperature was more efficient and thorough than microwave-assisted process (MAP) digestion in the preparation of speciation analysis; Most of the elements analyzed, excluding potassium and zinc, exist in particulate speciation in the plant; The transference characteristics of elements were associated with the polarity of extraction solvents. Contents of all 22 elements basically were directly proportional to the polarity of solvents varying from almost no polarity to strong, especially for 7 elements: magnesium, potassium, calcium, manganese, cobalt, thallium and lead.

A central neural circuit for itch sensation.

Although itch sensation is an important protective mechanism for animals, chronic itch remains a challenging clinical problem. Itch processing has been studied extensively at the spinal level. However, how itch information is transmitted to the brain and what central circuits underlie the itch-induced scratching behavior remain largely unknown. We found that the spinoparabrachial pathway was activated during itch processing and that optogenetic suppression of this pathway impaired itch-induced scratching behaviors. Itch-mediating spinal neurons, which express the gastrin-releasing peptide receptor, are disynaptically connected to the parabrachial nucleus via glutamatergic spinal projection neurons. Blockade of synaptic output of glutamatergic neurons in the parabrachial nucleus suppressed pruritogen-induced scratching behavior. Thus, our studies reveal a central neural circuit that is critical for itch signal processing.

Silencing of Cholinergic Basal Forebrain Neurons Using Archaerhodopsin Prolongs Slow-Wave Sleep in Mice.

The basal forebrain (BF) plays a crucial role in cortical activation. Our previous study showed that activation of cholinergic BF neurons alone is sufficient to suppress slow-wave sleep (SWS) and promote wakefulness and rapid-eye-movement (REM) sleep. However, the exact role of silencing cholinergic BF neurons in the sleep-wake cycle remains unclear. We inhibitied the cholinergic BF neurons genetically targeted with archaerhodopsin (Arch) with yellow light to clarify the role of cholinergic BF neurons in the sleep-wake cycle. Bilateral inactivation of cholinergic BF neurons genetically targeted with archaerhodopsin prolonged SWS and decreased the probability of awakening from SWS in mice. However, silencing these neurons changed neither the duration of wakefulness or REM sleep, nor the probability of transitions to other sleep-wake episodes from wakefulness or REM sleep. Furthermore, silencing these neurons for 6 h within the inactive or active period increased the duration of SWS at the expense of the duration of wakefulness, as well as increasing the number of prolonged SWS episodes (120-240 s). The lost wakefulness was compensated by a delayed increase of wakefulness, so the total duration of SWS and wakefulness during 24 h was kept stable. Our results indicate that the main effect of these neurons is to terminate SWS, whereas wakefulness or REM sleep may be determined by co-operation of the cholinergic BF neurons with other arousal-sleep control systems.

Selective activation of cholinergic basal forebrain neurons induces immediate sleep-wake transitions.

The basal forebrain (BF) plays a crucial role in cortical activation [1, 2]. However, the exact role of cholinergic BF (ch-BF) neurons in the sleep-wake cycle remains unclear [3, 4]. We demonstrated that photostimulation of ch-BF neurons genetically targeted with channelrhodopsin 2 (ChR2) was sufficient to induce an immediate transition to waking or rapid eye movement (REM) sleep from slow-wave sleep (SWS). Light stimulation was most likely to induce behavioral arousal during SWS, but not during REM sleep, a result in contrast to the previously reported photostimulation of noradrenergic or hypocretin neurons that induces wake transitions from both SWS and REM sleep. Furthermore, the ratio of light-induced transitions from SWS to wakefulness or to REM sleep did not significantly differ from that of natural transitions, suggesting that activation of ch-BF neurons facilitates the transition from SWS but does not change the direction of the transition. Excitation of ch-BF neurons during wakefulness or REM sleep sustained the cortical activation. Stimulation of these neurons for 1 hr induced a delayed increase in the duration of wakefulness in the subsequent inactive period. Our results suggest that activation of ch-BF neurons alone is sufficient to suppress SWS and promote wakefulness and REM sleep.