Neuronal and Molecular Mechanisms Underlying Chronic Pain and Depression Comorbidity in the Paraventricular Thalamus.

Patients with chronic pain often develop comorbid depressive symptoms, which makes the pain symptoms more complicated and refractory. However, the underlying mechanisms are poorly known. Here, in a repeated complete Freund's adjuvant (CFA) male mouse model, we reported a specific regulatory role of the paraventricular thalamic nucleus (PVT) glutamatergic neurons, particularly the anterior PVT (PVA) neurons, in mediating chronic pain and depression comorbidity (CDC). Our c-Fos protein staining observed increased PVA neuronal activity in CFA-CDC mice. In wild-type mice, chemogenetic activation of PVA glutamatergic neurons was sufficient to decrease the 50% paw withdrawal thresholds (50% PWTs), while depressive-like behaviors evaluated with immobile time in tail suspension test (TST) and forced swim test (FST) could only be achieved by repeated chemogenetic activation. Chemogenetic inhibition of PVA glutamatergic neurons reversed the decreased 50% PWTs in CFA mice without depressive-like symptoms and the increased TST and FST immobility in CFA-CDC mice. Surprisingly, in CFA-CDC mice, chemogenetically inhibiting PVA glutamatergic neurons failed to reverse the decrease of 50% PWTs, which could be restored by rapid-onset antidepressant S-ketamine. Further behavioral tests in chronic restraint stress mice and CFA pain mice indicated that PVA glutamatergic neuron inhibition and S-ketamine independently alleviate sensory and affective pain. Molecular profiling and pharmacological studies revealed the 5-hydroxytryptamine receptor 1D (Htr1d) in CFA pain-related PVT engram neurons as a potential target for treating CDC. These findings identified novel CDC neuronal and molecular mechanisms in the PVT and provided insight into the complicated pain neuropathology under a comorbid state with depression and related drug development.

The Impact of Esketamine Combined with Dexmedetomidine on Laparoscopic Gallbladder Surgery: A Randomized Controlled Trial.

Objective: To assess the efficacy of combining esketamine with dexmedetomidine in laparoscopic gallbladder surgery. Methods: We investigated 110 laparoscopic cholecystectomy patients at Jinan Central Hospital, affiliated with Shandong First Medical University, from April 2019 to March 2020. Patients were randomly assigned to the control group (n = 55) or observation group (n = 55). The control group received dexmedetomidine intravenously at 1 µg/kg and a continuous infusion at 0.5 µg•kg-1•h-1. The observation group received esketamine and dexmedetomidine, with intravenous esketamine at 0.4 mg/kg and a continuous infusion at 0.1 mg/(kg•h). We measured heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) at four-time points: before anesthesia (T0), 30 minutes after anesthesia (T1), extubation (T2), and awakening (T3). We also assessed wake time, post-anesthesia care unit (PACU) stay, and Ramasy and visual analogue scale (VAS) scores at 2, 6, 12, and 24 hours post-surgery. Results: At T0, no significant changes occurred in HR, SBP, and DBP in both groups (P > .05). However, at T1 and T2, HR, SBP, and DBP gradually decreased, with the control group exhibiting lower levels than the observation group (P < .05). These levels returned to baseline at T3. PACU residence and wake times showed no significant differences (P > .05). At 2 hours post-operation, Ramasy scores significantly dropped in the observation group versus the control group (P < .05). At 6, 12, and 24 hours post-operation, Ramasy scores exhibited no significant differences (P > .05). Moreover, at 2, 6, and 12 hours post-operation, VAS scores in the observation group were notably lower than in the control group (P < .05). At 24 hours post-operation, VAS scores revealed no significant differences (P > .05). Adverse reactions within 3 days post-operation did not differ significantly between the groups (P > .05). Conclusions: Combining esketamine with dexmedetomidine enhances the quality of laparoscopic cholecystectomy, alleviates postoperative agitation, accelerates cognitive function recovery, reduces cognitive function impairment, and merits clinical consideration.

Effects of Esketamine Combined with Propofol for Hysteroscopy Anesthesia on Patient Hemodynamics and Adverse Reactions.

Objective: To investigate the effect of esketamine combined with propofol on patient hemodynamics and its safety in hysteroscopy anesthesia. Methods: A total of 186 hysteroscopic patients admitted to our hospital from January 2021 to January 2022 were selected, and the patients were divided into group K and Group P according to a completely random number table, with 93 cases each. In short, all patients are uniformly numbered and adequately intermixed, according to the prescribed sampling starting point and order, the sample unit numbers were successively drawn from the random number table, until the extraction to the required sample size. Group K was given esketamine combined with propofol intravenously, and group P was given sufentanil combined with propofol intravenously. The changes in respiratory circulation [heart rate (HR), mean arterial pressure (MAP) and oxygen saturation (SpO2)] at the time of entering the operating room (T0), at the beginning of surgery (T1), 10 minutes after surgery(T2), and 10 minutes after the end of surgery (T3) were compared between the two groups, as well as the total time of surgery, the time to wake up after surgery, the amount of propofol used intraoperatively and the proportion of additional propofol were compared. The numerical rating scale (NRS) was used to assess the pain level of patients in both groups at different times after awakening and the occurrence of intraoperative and postoperative adverse reactions such as body movement, respiratory depression, bradycardia, injection site pain, nausea and vomiting, and dizziness were counted in both groups. Results: There were no significant changes in MAP, HR, and SpO2 in Group K at all moments compared with T0 (P > .05), MAP, HR and SpO2 in Group P at T1 and T2 were lower than those at T0 (P < .05). MAP, HR, and SpO2 were significantly lower in Group P at T1 and T2 moments compared with Group K, suggesting that circulatory depression was more pronounced in Group P at T1 and T2 moments (P < .05) and was not conducive to postoperative recovery. Compared with group P, the postoperative recovery time of group K was significantly shorter, and the dosage of propofol and the proportion of additional propofol were significantly lower (P < .05) which was beneficial to the health of patients. The pain level was significantly lower in Group K at 5, 15, and 30 minutes after awakening than in Group P (P < .05). The incidence of adverse reactions such as intraoperative motion, respiratory depression, bradycardia, injection site pain, and dizziness was significantly lower in group K than in group P (P < .05), and there was no significant difference in the incidence of nausea and vomiting between the two groups (P > .05), and prove that esketamine combined with propofol used for anesthesia which have high safety as well as more effective. Conclusion: The use of esketamine compounded with propofol in hysteroscopy anesthesia has less effect on the patient's circulatory and respiratory systems. This protocol can improve the postoperative analgesic effect of anesthesia in patients, reduce the amount of propofol during surgery, have fewer adverse effects and mild symptoms, is safe and effective, and can be used in clinical practice.

Esketamine accelerates emergence from isoflurane general anaesthesia by activating the paraventricular thalamus glutamatergic neurones in mice.

BACKGROUND: Delayed emergence from general anaesthesia poses a significant perioperative safety hazard. Subanaesthetic doses of ketamine not only deepen anaesthesia but also accelerate recovery from isoflurane anaesthesia; however, the mechanisms underlying this phenomenon remain elusive. Esketamine exhibits a more potent receptor affinity and fewer adverse effects than ketamine and exhibits shorter recovery times after brief periods of anaesthesia. As the paraventricular thalamus (PVT) plays a pivotal role in regulating wakefulness, we studied its role in the emergence process during combined esketamine and isoflurane anaesthesia. METHODS: The righting reflex and cortical electroencephalography were used as measures of consciousness in mice during isoflurane anaesthesia with coadministration of esketamine. The expression of c-Fos was used to determine neuronal activity changes in PVT neurones after esketamine administration. The effect of esketamine combined with isoflurane anaesthesia on PVT glutamatergic (PVTGlu) neuronal activity was monitored by fibre photometry, and chemogenetic technology was used to manipulate PVTGlu neuronal activity. RESULTS: A low dose of esketamine (5 mg kg-1) accelerated emergence from isoflurane general anaesthesia (474 [30] s vs 544 [39] s, P=0.001). Esketamine (5 mg kg-1) increased PVT c-Fos expression (508 [198] vs 258 [87], P=0.009) and enhanced the population activity of PVTGlu neurones (0.03 [1.7]% vs 6.9 [3.4]%, P=0.002) during isoflurane anaesthesia (1.9 [5.7]% vs -5.1 [5.3]%, P=0.016) and emergence (6.1 [6.2]% vs -1.1 [5.0]%, P=0.022). Chemogenetic suppression of PVTGlu neurones abolished the arousal-promoting effects of esketamine (459 [33] s vs 596 [33] s, P<0.001). CONCLUSIONS: Our results suggest that esketamine promotes recovery from isoflurane anaesthesia by activating PVTGlu neurones. This mechanism could explain the rapid arousability exhibited upon treatment with a low dose of esketamine.

Inhaled Litsea glaucescens K. (Lauraceae) leaves' essential oil has anxiolytic and antidepressant-like activity in mice by BDNF pathway activation.

ETHNOPHARMACOLOGICAL RELEVANCE: Litsea glaucescens K. (Lauraceae) is a small tree from the Mexican and Central American temperate forests, named as "Laurel". Its aromatic leaves are ordinarily consumed as condiments, but also are important in Mexican Traditional Medicine, and among the most important non wood forest products in this area. The leaves are currently used in a decoction for the relief of sadness by the Mazahua ethnic group. Interestingly, "Laurel" has a long history. It was named as "Ehecapahtli" (wind medicine) in pre-Columbian times and applied to heal maladies correlated to the Central Nervous System, among them depression, according to botanical texts written in the American Continent almost five centuries ago. AIM OF THE STUDY: Depression is the first cause of incapacity in the world, and society demands alternative treatments, including aromatherapy. We have previously demonstrated the antidepressant-like activity of L. glaucescens leaves' essential oil (LEO), as well as their monoterpenes linalool, and beta-pinene by intraperitoneal route in a mice behavioral model. Here we now examined if LEO and linalool exhibit this property and anxiolytic activity when administered to mice by inhalation. We also investigated if these effects occur by BDNF pathway activation in the brain. MATERIALS AND METHODS: The LEO was prepared by distillation with water steam and analyzed by gas chromatography-mass spectrometry (GC-MS). The monoterpenes linalool, eucalyptol and ß-pinene were identified and quantified. Antidepressant type properties were determined with the Forced Swim Test (FST) on mice previously exposed to LEO or linalool in an inhalation chamber. The spontaneous locomotor activity and the sedative effect were assessed with the Open Field Test (OFT), and the Exploratory Cylinder (EC), respectively. The anxiolytic properties were investigated with the Elevated Plus Maze Apparatus (EPM) and the Hole Board Test (HBT). All experiments were video documented. The mice were subjected to euthanasia, and the brain hippocampus and prefrontal cortex were dissected. RESULTS: The L. glaucescens essential oil (LEO) contains 31 compounds according to GC/MS, including eucalyptol, linalool and beta-pinene. The LEO has anxiolytic effect by inhalation in mice, as well as linalool, and ß-pinene, as indicated by OFT and EC tests. The LEO and imipramine have antidepressant like activity in mice as revealed by the FST; however, linalool and ketamine treatments didn't modify the time of immobility. The BDNF was increased in FST in mice treated with LEO in both areas of the brain as revealed by Western blot; but did not decrease the level of corticosterone in plasma. The OFT indicated that LEO and imipramine didn't reduce the spontaneous motor activity, while linalool and ketamine caused a significant decrease. CONCLUSION: Here we report by the first time that L. glaucescens leaves essential oil has anxiolytic effect by inhalation in mice, as well as linalool, and ß-pinene. This oil also maintains its antidepressant-like activity by this administration way, similarly to the previously determined intraperitoneally. Since inhalation is a common administration route for humans, our results suggest L. glaucescens essential oil deserve future investigation due to its potential application in aromatherapy.

Investigating Deep Sedation With Intravenous Ketamine in Spontaneous Respiration During Pulsed-Field Ablation.

OBJECTIVES: The authors report their experience of a protocol for deep sedation with ketamine in spontaneous respiration during the pulsed-field ablation (PFA) of atrial fibrillation (AF). DESIGN: Observational, prospective, nonrandomized fashion. SETTING: Single-center hospitalized patients. PARTICIPANTS: All consecutive patients undergoing PFA of AF. INTERVENTIONS: Patients undergoing deep sedation with intravenous ketamine. MEASUREMENTS AND MAIN RESULTS: The authors' sedation protocol involves the intravenous administration of fentanyl (1.5 µg/kg) and midazolam (2 mg) at low doses before local anesthesia with lidocaine. A ketamine adjunct (1 mg/kg) in 5-minute boluses was injected about 5 minutes before the first PFA delivery. The authors enrolled 117 patients (age = 59 ± 10 y, 74.4% males, body mass index = 27.6 ± 5 kg/m2, fluoroscopy time = 24 ± 14 minutes, skin-to-skin time = 80 ± 40 minutes and PFA LA dwell time = 24 ± 7 minutes). By the end of the procedure, pulmonary vein isolation had been achieved in all patients using PFA alone. The mean time under sedation was 54.9 ± 6 minutes, with 92 patients (79%) being sedated for <1 hour. A satisfactory Ramsay Sedation Scale level before ketamine administration was achieved in all patients, except one (80.3% of the patients with rank 3; 18.4% with rank 2). In all procedures, the satisfaction level was found acceptable by both the patient and the primary operator (satisfactory in 98.2% of cases). All patients achieved a Numeric Rating Scale for Pain ≤3 (none or mild). No major procedure or anesthesia-related complications were reported. CONCLUSION: The authors' standardized sedation protocol with the administration of drugs with rapid onset and pharmacologic offset at low doses was safe and effective, with an optimal degree of patient and operator satisfaction.

Cognition Enhancing Potential of Aqueous Leaf Extract of Amaranthus dubius in Mice.

Amaranthus dubius is a vegetable consumed for its nutritional content in Kenya. In herbal medicine, A. dubius is utilized to relief fever, anemia and hemorrhage. Additionally, it is utilized to manage cognitive dysfunction and is considered to augment brain function, but there is no empirical evidence to support this claim. The contemporary study investigated cognitive enhancing potential of A. dubius in mice model of Alzheimer's disease (AD)-like dementia induced with ketamine. Cognitively damaged mice were treated with aqueous extract of A. dubius leaf upon which passive avoidance task (PAT) was used to assess the cognitive performance. At the end of passive avoidance test, brains of the mice were dissected to evaluate the possibility of the extract to inhibit hallmarks that propagate AD namely oxidative stress and acetylcholinesterase activity. Additionally, characterization of secondary metabolites was done using liquid chromatograph- mass spectrometry analysis. During PAT test, extract-treated mice showed significantly increased step-through latencies than AD mice, depicting ability of A. dubius to reverse ketamine-induced cognitive decline. Further, the extract remarkably lowered malondialdehyde levels to normal levels and effectively inhibited acetylcholinesterase enzyme. The study showed that A. dubius extract is endowed with phytoconstituents that possess anti-oxidant and anticholinesterase activities. Thus, this study confirmed promising therapeutic effects of 200, 300 and 400 mg/kg bw of A. dubius extract with potential to alleviate cognitive disarray observed in AD.

Serotonin is a common thread linking different classes of antidepressants.

Depression pathology remains elusive. The monoamine hypothesis has placed much focus on serotonin, but due to the variable clinical efficacy of monoamine reuptake inhibitors, the community is looking for alternative therapies such as ketamine (neurogenesis theory of antidepressant action). There is evidence that different classes of antidepressants may affect serotonin levels; a notion we test here. We measure hippocampal serotonin in mice with voltammetry and study the effects of acute challenges of escitalopram, fluoxetine, reboxetine, and ketamine. We find that pseudo-equivalent doses of these drugs similarly raise ambient serotonin levels, despite their differing pharmacodynamics because of differences in Uptake 1 and 2, rapid SERT trafficking, and modulation of serotonin by histamine. These antidepressants have different pharmacodynamics but have strikingly similar effects on extracellular serotonin. Our findings suggest that serotonin is a common thread that links clinically effective antidepressants, synergizing different theories of depression (synaptic plasticity, neurogenesis, and the monoamine hypothesis).

The potent analgesia of intrathecal 2R, 6R-HNK via TRPA1 inhibition in LF-PENS-induced chronic primary pain model.

BACKGROUND: Chronic primary pain (CPP) is an intractable pain of unknown cause with significant emotional distress and/or dysfunction that is a leading factor of disability globally. The lack of a suitable animal model that mimic CPP in humans has frustrated efforts to curb disease progression. 2R, 6R-hydroxynorketamine (2R, 6R-HNK) is the major antidepressant metabolite of ketamine and also exerts antinociceptive action. However, the analgesic mechanism and whether it is effective for CPP are still unknown. METHODS: Based on nociplastic pain is evoked by long-term potentiation (LTP)-inducible high- or low-frequency electrical stimulation (HFS/LFS), we wanted to develop a novel CPP mouse model with mood and cognitive comorbidities by noninvasive low-frequency percutaneous electrical nerve stimulation (LF-PENS). Single/repeated 2R, 6R-HNK or other drug was intraperitoneally (i.p.) or intrathecally (i.t.) injected into naïve or CPP mice to investigate their analgesic effect in CPP model. A variety of behavioral tests were used to detect the changes in pain, mood and memory. Immunofluorescent staining, western blot, reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) and calcium imaging of in cultured dorsal root ganglia (DRG) neurons by Fluo-8-AM were used to elucidate the role and mechanisms of 2R, 6R-HNK in vivo or in vitro. RESULTS: Intrathecal 2R, 6R-HNK, rather than intraperitoneal 2R, 6R-HNK or intrathecal S-Ketamine, successfully mitigated HFS-induced pain. Importantly, intrathecal 2R, 6R-HNK displayed effective relief of bilateral pain hypersensitivity and depressive and cognitive comorbidities in a dose-dependent manner in LF-PENS-induced CPP model. Mechanically, 2R, 6R-HNK markedly attenuated neuronal hyperexcitability and the upregulation of calcitonin gene-related peptide (CGRP), transient receptor potential ankyrin 1 (TRPA1) or vanilloid-1 (TRPV1), and vesicular glutamate transporter-2 (VGLUT2) in peripheral nociceptive pathway. In addition, 2R, 6R-HNK suppressed calcium responses and CGRP overexpression in cultured DRG neurons elicited by the agonists of TRPA1 or/and TRPV1. Strikingly, the inhibitory effects of 2R, 6R-HNK on these pain-related molecules and mechanical allodynia were substantially occluded by TRPA1 antagonist menthol. CONCLUSIONS: In the newly designed CPP model, our findings highlighted the potential utility of intrathecal 2R, 6R-HNK for preventing and therapeutic modality of CPP. TRPA1-mediated uprgulation of CGRP and neuronal hyperexcitability in nociceptive pathways may undertake both unique characteristics and solving process of CPP.

Electroacupuncture attenuates ketamine-induced neuronal injury in the locus coeruleus of rats through modulation of the CAMK II/CREB pathway.

BACKGROUND: Ketamine, despite its efficacy in treating depression, raises concerns regarding safety due to potential abuse, cognitive impairment, and bladder toxicity. Ketamine can affect the locus coeruleus (LC) norepinephrine and attention networks. This study explored the protective effects of electroacupuncture (EA) on the LC of rats exposed to repeated administration of ketamine while investigating the potential role of the Calcium CaM-dependent protein kinase II (CAMK II)/ cAMP response element binding protein (CREB) pathway in mediating EA's impact on ketamine-induced neuronal injury in LC. METHODS: Rats were repeatedly injected intraperitoneally with ketamine hydrochloride (50 mg/kg) once daily for seven days. Subsequently, EA was performed at the acupoints "Zusanli" (ST36) and "Sanyinjiao" (SP-6) once daily following ketamine administration. The Morris water maze test was employed to assess behavioral changes in the rats. Neuronal injury was examined using Nissl staining, and the expression of CAMK II, CREB, and phospho-CREB (p-CREB) was evaluated through immunohistochemistry and western blotting. RESULTS: EA mitigated the cognitive and exploratory impairments and attenuated neuronal injury in the LC induced by repeated administration of ketamine. The expression of CAMK II and p-CREB proteins in the LC increased following 7 days of ketamine administration. However, EA treatment led to a downregulation of CAMK II and p-CREB expression. CONCLUSION: Repeated administration of ketamine in male rats can lead to neuronal injury and neurobehavioral dysfunction. However, EA was found to ameliorate neurodegeneration in the LC and enhance neurobehavioral symptoms. This therapeutic effect of EA may be attributed to its modulation of the CAMKII/CREB pathway, thereby mitigating the aforementioned adverse effects.

Have Effective Antidepressants Finally Arrived? Developments in Major Depressive Disorder Therapy.

Among the greatest unmet needs in major depressive disorder (MDD) is a lack of effective pharmacotherapies for patients who do not respond to first- and second-line antidepressant medications. After decades of muted progress, optimism regarding the future of MDD therapy rose after scientists serendipitously uncovered the antidepressant effects of ketamine. The discovery of ketamine's antidepressant effects inspired the search for related newer medications, such as S-ketamine. Orally administered NMDA antagonists have also demonstrated considerable promise in recently concluded, late-stage clinical trials. Researchers evaluating an extended-release combination of bupropion (105 mg) and dextromethorphan (45 mg) found that recipients experienced a decline in MADRS total score. Neurosteroids, such as brexanolone and zuranolone, appear to represent another class of antidepressants. These drugs appear to modulate GABA neurotransmission, which has long been known to be a pathway for drugs that are used to treat insomnia and anxiety. After nearly 50 years of legal injunctions against their use, psychedelic drugs have attracted interest among researchers seeking alternative antidepressants. Psilocybin, derived from mushrooms, remains under investigation for its benefits in treatment-resistant depression.

Arketamine for bipolar depression: Open-label, dose-escalation, pilot study.

There are significantly fewer options for the treatment of bipolar depression than major depressive disorder, with an urgent need for alternative therapies. In this pilot study, we treated six subjects with bipolar disorder types I and II (according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria) who had been in a current depressive episode for at least four weeks. Four subjects were female (66.66%), and the mean age was 45.33 (±12.32). Subjects received adjunct treatment with two arketamine intravenous infusions one week apart-0.5 mg/kg first and then 1 mg/kg. The mean baseline Montgomery-Åsberg Depression Rating Scale (MADRS) total score was 36.66, which decreased to 27.83 24h after the first infusion of 0.5 mg/kg of arketamine (p = 0.036). In respect of the 1 mg/kg dose, the mean MADRS total score before the second infusion was 32.0, which dropped to 17.66 after 24h (p < 0.001). Arketamine appears to have rapid-acting antidepressant properties, consistent with previous animal studies on major depression. All individuals tolerated both doses, exhibiting nearly absent dissociation, and no manic symptoms. To the best of our knowledge, this pilot trial is the first to test the feasibility and safety of the (R)-enantiomer of ketamine (arketamine) for bipolar depression.

Psychedelics and Related Pharmacotherapies as Integrative Medicine for Older Adults in Palliative Care.

Psychological distress at the end of life is a common experience that lacks effective treatments. This is in part due to the multidimensional nature of psychological distress at the end of life, encompassing an interplay between psychosocial and existential distress as well as physical symptom burden. Research shows that psychedelic-assisted therapy is an effective treatment of end of life distress. Ketamine and cannabis may help with quick and effective treatment of symptom burden at the end of life. Although these novel interventions show promise, further data is needed, particularly in elderly populations.

Acupuncture in the Anesthetic Recovery of Bitches Submitted to Ovariohysterectomy.

Background: Cardiorespiratory depression caused by anesthesia decreases the quality and increases the time of postoperative recovery. The acupoint Governor Vessel 26 (GV26) is a resuscitation point that can reverse this depression and can be safely used without side effects. Objectives: The objective of this study was to evaluate the stimulation and anesthetic recovery time of GV26 in bitches submitted to ovariohysterectomy (OH) under dissociative anesthesia. Methods: As pre-anesthetic protocol, acepromazine 0.2% (0.1 mg/kg) and tramadol hydrochloride (2 mg/kg) was used, and induction was performed using midazolam (0.5 mg/kg) and ketamine (10 mg/kg). For the control group, standard procedure was performed for OH, with anesthetic recovery and post-surgical procedures. For the acupuncture group (AP), the stimulation of acupoint GV26 was performed 20 minutes after the anesthetic induction and maintained for 5 minutes. Respiratory rate, amplitude (superficial, normal or deep), type of respiratory movement (abdominal, abdominocostal or thoracoabdominal), heart rate, capillary filling time, temperature, presence or absence of laryngotracheal reflex, presence or absence of interdigital reflexes were assessed immediately before PAM application, and 2 (T1), 5 (T2), 10 (T3), 15 (T4), 20 (T5), 25 (T6) and 30 (T7) minutes after treatment. The results were tabulated and statistically analyzed. Results: When comparing the AP group with the control group, an improvement in amplitude of the chest cage was observed at all times, where the animals remained in normal or deep respiratory amplitude. The heart rate was significantly higher for the AP group (155.5 ± 34.4 bpm) than the control group at T1 (105.1 ± 15.4 bpm), while recovery time was lower for the AP group (54.1 ± 14.9 min) when compared to control group (79.9 ± 17.9 min). Conclusion: The present paper demonstrated the efficacy of GV26 in maintaining adequate respiratory amplitude and decreasing the anesthetic recovery time.

Anxiolytic-like effects of an mGluR 5 antagonist and a mGluR 2/3 agonist, and antidepressant-like effects of an mGluR 7 agonist in the chick social separation stress test, a dual-drug screening model of treatment-resistant depression.

Modulation of glutamate receptors has demonstrated anxiolytic and/or antidepressant effects in rodent stress models. The chick social-separation stress paradigm exposes socially raised aves to an isolation stressor which elicits distress vocalizations (DVocs) in an attempt to re-establish contact. The model presents a state of panic during the first 5 min followed by a state of behavioral despair during the last 60 to 90 min. Making it useful as a dual anxiolytic/antidepressant screening assay. Further research has identified the Black Australorp strain as a stress-vulnerable, treatment-resistant, and ketamine-sensitive genetic line. Utilizing this genetic line, we sought to evaluate modulation of glutamatergic receptors for potential anxiolytic and/or antidepressant effects. Separate dose-response studies were conducted for the following drugs: the AMPA PAM LY392098, the mGluR 5 antagonist MPEP, the mGluR 2/3 agonist LY404039, the mGluR 2/3 antagonist LY341495, and the mGluR 7 agonist AMN082. The norepinephrine α2 agonist clonidine and the NMDA antagonist ketamine were included as comparison for anxiolytic (anti-panic) and antidepressant effects, respectively. As in previous studies, clonidine reduced DVoc rates during the first 5 min (attenuation of panic) and ketamine elevated DVoc rates (attenuation of behavioral despair) during the last 60 min of isolation. The mGluR 2/3 agonist LY404039 and the mGluR 5 antagonist MPEP decreased DVoc rates during the first 5 min of isolation indicative of anxiolytic effects like that of clonidine while the mGluR 7 agonist AMN082 elevated DVoc rates in the later hour of isolation, representative of antidepressant effects like that of ketamine. Collectively, these findings suggest that certain glutamate targets may be clinically useful in treating panic disorder and/or treatment-resistant depression.

Pharmacotherapy optimization for rapid sequence intubation in the emergency department.

PURPOSE: Rapid-sequence intubation (RSI) is the process of administering a sedative and neuromuscular blocking agent (NMBA) in rapid succession to facilitate endotracheal intubation. It is the most common and preferred method for intubation of patients presenting to the emergency department (ED). The selection and use of medications to facilitate RSI is critical for success. The purpose of this review is to describe pharmacotherapies used during the RSI process, discuss current clinical controversies in RSI medication selection, and review pharmacotherapy considerations for alternative intubation methods. SUMMARY: There are several steps to the intubation process requiring medication considerations, including pretreatment, induction, paralysis, and post-intubation sedation and analgesia. Pretreatment medications include atropine, lidocaine, and fentanyl; but use of these agents in clinical practice has fallen out of favor as there is limited evidence for their use outside of select clinical scenarios. There are several options for induction agents, though etomidate and ketamine are the most used due to their more favorable hemodynamic profiles. Currently there is retrospective evidence that etomidate may produce less hypotension than ketamine in patients presenting with shock or sepsis. Succinylcholine and rocuronium are the preferred neuromuscular blocking agents, and the literature suggests minimal differences between succinylcholine and high dose rocuronium in first-pass success rates. Selection between the two is based on patient specific factors, half-life and adverse effect profiles. Finally, medication-assisted preoxygenation and awake intubation are less common methods for intubation in the ED but require different considerations for medication use. AREAS FOR FUTURE RESEARCH: The optimal selection, dosing, and administration of RSI medications is complicated, and further research is needed in several areas. Additional prospective studies are needed to determine optimal induction agent selection and dosing in patients presenting with shock or sepsis. Controversy exists over optimal medication administration order (paralytic first vs induction first) and medication dosing in obese patients, but there is insufficient evidence to significantly alter current practices regarding medication dosing and administration. Further research examining awareness with paralysis during RSI is needed before definitive and widespread practice changes to medication use during RSI can be made.

Real-world study of intranasal ketamine for use in patients with refractory chronic migraine: a retrospective analysis.

INTRODUCTION: Subanesthetic ketamine infusion has been used for managing refractory headache in inpatient or outpatient infusion settings. Intranasal ketamine may be an alternative option for outpatient care. METHODS: A retrospective study was conducted at a single tertiary headache center to assess the clinical effectiveness and tolerability of intranasal ketamine in patients with refractory chronic migraine. Candidates who received intranasal ketamine between January 2019 and February 2020 were screened through an electronic medical record query. Manual chart reviews and structured telephone interviews were conducted on obtaining informed consent. RESULTS: Of 242 subjects screened, 169 (79.9% women) of median (IQR) age 44 (22) years were interviewed. They reported a median (IQR) of 30 (9) monthly headache days and tried 4 (1) classes of preventive medications. Overall, they used 6 (6) sprays per day, with a median (IQR) of spray use of 10 (11) days per month. Intranasal ketamine was reported as 'very effective' in 49.1% and the quality of life was considered 'much better' in 35.5%. At the time of the interview, 65.1% remained current intranasal ketamine users and 74.0% reported at least one adverse event. CONCLUSION: In this descriptive study, intranasal ketamine served as an acute treatment for refractory chronic migraine by reducing headache intensity and improving quality of life with relatively tolerable adverse events. Most patients found intranasal ketamine effective and continued to use it despite these adverse events. Given the potential for overuse, it should be reserved for those clearly in need of more effective rescue treatment with appropriate safety precautions. Well-designed prospective placebo-controlled trials are necessary to demonstrate the efficacy and safety of intranasal ketamine in patients with migraine.

Assessment of Initial Depressive State and Pain Relief With Ketamine in Patients With Chronic Refractory Pain.

Importance: Repeated ketamine administration is common in treatment-refractory chronic pain, but ketamine analgesic and antidepressant effects are poorly understood in patients with chronic pain with depression symptoms. Objective: To determine clinical pain trajectories with repeated ketamine administrations, exploring whether ketamine dose and/or pretreatment depressive and/or anxiety symptoms may mediate pain relief. Design, Setting, and Participants: This nationwide, multicenter, prospective cohort study included patients in France with treatment-refractory chronic pain who received repeated ketamine administration, over 1 year, according to ketamine use in their pain clinic. Data were collected from July 7, 2016, through September 21, 2017. Linear mixed models for repeated data, trajectory analysis, and mediation analysis were performed from November 15 to December 31, 2022. Interventions: Ketamine administration in cumulative dose (milligrams) over 1 year. Main Outcomes and Measures: Primary outcome was mean pain intensity (0-10 on the Numerical Pain Rating Scale [NPRS]), assessed every month for 1 year by telephone, after inclusion in the hospital. Depression and anxiety (Hospital Anxiety and Depression Scale [HADS]), quality of life (12-item Short Form Health Survey [SF-12]), cumulative ketamine dose, adverse effects, and concomitant treatments were secondary outcomes. Results: A total of 329 patients (mean [SD] age, 51.4 [11.0] years; 249 women [75.7%] and 80 men [24.3%]) were enrolled. Repeated ketamine administration was associated with a decrease of NPRS (effect size = -0.52 [95% CI, -0.62 to -0.41]; P < .001) and an increase of SF-12 mental health (39.7 [10.9] to 42.2 [11.1]; P < .001) and physical health (28.5 [7.9] to 29.5 [9.2]; P = .02) dimension scores over 1 year. Adverse effects were in the normal range. There was a significant difference between patients without and with depressive symptoms in pain diminution (regression coefficient, -0.04 [95% CI, -0.06 to -0.01]; omnibus P = .002 for interaction of time × baseline depression [HADS score ≤7 or >7]). The mediation model showed that ketamine dose was not associated with pain diminution (r = 0.01; P = .61) and not correlated with depression (r = -0.06; P = .32), and that depression was associated with pain diminution (regression coefficient, 0.03 [95% CI, 0.01-0.04]; P < .001), whereas ketamine dose was not (regression coefficient, 0.00 [95% CI, -0.01 to 0.01]; P = .67). The proportion of reduction of pain mediated by baseline depression was 64.6%. Conclusions and Relevance: The findings of this cohort study on chronic refractory pain suggest that depression (and not ketamine dose or anxiety) was the mediator of the association of ketamine with pain diminution. This finding provides radically new insights on how ketamine reduces pain primarily by dampening depression. This reinforces the need for systematic holistic assessment of patients with chronic pain to diagnose severe depressive symptoms where ketamine would be a very valuable therapeutic option.

Effect of magnesium sulfate with ketamine infusions on intraoperative and postoperative analgesia in cancer breast surgeries: a randomized double-blind trial

Abstract Background Opioids are the cornerstone in managing postoperative pain; however, they have many side effects. Ketamine and Magnesium (Mg) are NMDA receptor antagonists used as adjuvant analgesics to decrease postoperative opioid consumption. Objective We assumed that adding Mg to ketamine infusion can improve the intraoperative and postoperative analgesic efficacy of ketamine infusion alone in cancer breast surgeries. Methods Ninety patients aged between 18 and 65 years and undergoing elective cancer breast surgery were included in this prospective randomized, double-blind study. Group K received ketamine 0.5 mg.kg-1 bolus then 0.12 mg.kg-1.h-1 infusion for the first 24 hours postoperatively. Group KM: received ketamine 0.5 mg.kg-1 and Mg sulfate 50 mg.kg-1, then ketamine 0.12 mg.kg-1.h-1 and Mg sulfate 8 mg.kg-1.h-1 infusions for the first 24 hours postoperative. The primary outcome was the morphine consumption in the first 24 hours postoperative, while the secondary outcomes were: intraoperative fentanyl consumption, NRS, side effects, and chronic postoperative pain. Results Group KM had less postoperative opioid consumption (14.12 ± 5.11 mg) than Group K (19.43 ± 6.8 mg). Also, Group KM had less intraoperative fentanyl consumption. Both groups were similar in postoperative NRS scores, the incidence of side effects related to opioids, and chronic neuropathic pain. Conclusion Adding Mg to ketamine infusion can safely improve intraoperative and postoperative analgesia with opioid-sparing effect in cancer breast surgery.