A novel model of drug cue-induced behaviours in rhesus macaque subjected to chronic ketamine exposure

To the Editor,Non-human primate(NHP)models are advantageous for mimicking human addiction with high behavioural validity.1 However,current NHP drug addiction models(eg,self-administration)often require a comprehensive behavioural training paradigm,relatively expensive apparatus and invasive surgical procedures.

Efficacy of repeated intravenous esketamine in adolescents with anxious versus non-anxious depression

Background Patients with anxious major depressive disorder(MDD)are more likely to have poorer outcomes than those with non-anxious MDD.However,the effect of esketamine on adolescents with anxious versus non-anxious MDD has remained unknown.Aims We compared the efficacy of esketamine in adolescents with MDD and suicidal ideation,both anxious and non-anxious.Methods Fifty-four adolescents with anxious(n=33)and non-anxious(n=21)MDD received three infusions of esketamine 0.25mg/kg or active-placebo(midazolam 0.045 mg/kg)over 5 days,with routine inpatient care and treatment.Suicidal ideation and depressive symptoms were assessed using the Columbia Suicide Severity Rating Scale and the Montgomery-Asberg Depression Rating Scale.Multiple-sample proportional tests were used to compare the differences between groups on treatment outcomes 24 hours after the final infusion(day 6,primacy efficacy endpoint)and throughout the 4-week post-treatment(days 12,19 and 33).Results In subjects who received esketamine,a greater number of patients in the non-anxious group than the anxious group achieved antisuicidal remission on day 6(72.7%vs 18.8%,p=0.015)and day 12(90.9%vs 43.8%,p=0.013),and the non-anxious group had a higher antidepressant remission rate compared with the anxious group on day 33(72.7%vs 26.7%,p=0.045).No significant differences in treatment outcomes were observed between the anxious and non-anxious groups at other time points.Conclusions Three infusions of esketamine as an adjunct to routine inpatient care and treatment had a greater immediate post-treatment antisuicidal effect in adolescents with non-anxious MDD than in those with anxious MDD;however,this benefit was temporary and was not maintained over time.

Virtual Reality as an Adjunct to Ketamine Infusion Therapy Increases Patient Satisfaction in the Management of Chronic Pain and Depression: A Retrospective Pilot Study

The management of patients with concomitant chronic pain (CP) and Major Depressive Disorder (MDD) remains challenging for clinicians. Current chronic pharmacologic management is often unsuccessful, or has intolerable side effects to the patients. While not restricted to patients with chronic pain, these patients are often diagnosed with depression, presenting with symptoms such as poor mood, anhedonia, and altered cognitive processes. It is estimated that a substantial proportion of treated patients do not derive a substantive benefit from traditional pharmacological treatments for depression. The present study involved a retrospective review of cases, exploring the patient-reported satisfaction with and tolerability of a novel use of virtual reality (VR), coined KVR, as an adjunct to intravenous ketamine infusion therapies. Specifically, the ketamine-virtual reality protocol was employed as a potential adjunctive intervention for patients suffering from chronic pain and depression. Visual Analog Scores (VAS) associated with pain were significantly lower on the third than on the first assessment day. Montgomery-?sberg Depression Rating Scale (MADRS) scores improved following infusion and across days (i.e., sessions). Lastly, 2/3 of patients preferred the use of VR with their ketamine infusion. The results are considered in terms of implementing prospective studies to examine whether the combination therapies have a synergistic benefit and the nature and magnitude of clinically meaningful treatment effects, if any.

Administration of Nebulised Ketamine for Managing Pain in the Intensive Care Unit of Obstetrics and Gynaecology

Introduction: The use of inhaled ketamine to manage a variety of painful conditions has been endorsed by the American College of Emergency Physicians and the American Academy of Emergency Medicine. Nebulized analgesia has multiple benefits, including rapid, effective and titratable analgesic delivery. The aim of our study is to assess the efficacy and safety of intranasal analgesic-dose ketamine compared to multimodal analgesia in patients presenting with acute postoperative pain or headache after a spinal anaesthetic in the intensive care unit of obstetrics and gynaecology. Materials and Methods: This was a prospective descriptive study, with hospital Ethics Committee approval and written informed consent from study participants. We compared the effect of nebulized ketamine and multimodal analgesia postoperatively in 120 patients belonging to the physical status I - II of the American Society of Anesthesiologists, in the intensive care unit of obstetrics and gynaecology, at the Ibn Rochd University Hospital Center in Casablanca from June 2021 to June 2022. Results: We included 120 patients in our study divided into two groups of 60 patients: the average age was 35 years, with extremes ranging from 18 to 45 years, All patients were hospitalized for postoperative care: all women underwent locoregional anaesthesia with a standard dose according to the service protocol (10 mg of bupivacaine, 25γ of fentanyl, 100γ of morphine), where pain was the common denominator. Among these patients, 59 were admitted for management of postpartum haemorrhage, 43 for postoperative monitoring, 15 for post-spinal anaesthesia headache and 3 for pelviperitonitis. The results of the pain assessment 30 minutes after the ketamine nebulization were marked by a request for analgesia in 12 patients, which is 20% of group A, including 5 patients, whose visual analogue scale (VAS) on admission was between 5 and 7, and 7 patients whose VAS at admission was ≥8;all these patients received a second dose of ketamine by nebulization;the evaluation 30 min after the second dose was marked by a request for analgesia in 4 patients, which is 7% of Group A;in all these patients the VAS at admission was ≥8. Of the total number of patients of Group A, only 4 received morphine when they were requested for analgesia after the second dose of nebulized ketamine. Conclusion: The primary outcome of nebulized ketamine use is a significant reduction in VAS pain score. We believe that nebulized ketamine has a potential effect of reducing pain in the intensive care unit of obstetrics and gynaecology;this may be an additional analgesic modality for clinicians to provide rapid, effective and non-invasive pain relief.

Ketamine和Bicucullin对帕金森模型的影响

目的 为帕金森氏病的发病机理及兴奋性氨基酸受体拮抗剂对帕金森氏病的防治提供理论根据。方法 本实验采用MPTP腹腔注射建立C57BL小黑鼠帕金森氏病模型的过程中 ,同时用兴奋性氨基酸NMDA受体拮抗剂Ketamine和GABA受体拮抗剂Bicucullin ,观察其帕金森行为症状、病理变化及生化改变。结果 Ketamine加MPTP组和Bicucullin加MPTP组及MPTP组和生理盐水组比较 ,上述指标都有明显改变。结论 NMDA受体拮抗剂对小鼠帕金森氏病模型具有防治作用 ,GABA神经元的功能降低可加重帕金森氏病的症状。

Effect of propofol and ketamine anesthesia on cognitive function and immune function in young rats

Objective:To investigate the effects of propofol and ketamine on the cognitive function and immune function in young rats.Method:A total of 80 young rats were randomly divided into four groups:Control group,ketamine group(experimental group A),propofol group(experimental group B),ketamine and propofol group(experimental group Q.All rats had continuous injection for three times,serum IL-2,IL-4 and II.-10 and whole brain IL-I P level,hippocampal neuronal apoptosis level were measured.The cognitive ability in rats was tested by water maze.Results:Water maze test showed on the 1st d,the maze test latency of the control group,the experimental group B and the experimental group C water were decreased gradually;Compared with the control group after 3 days,the latency of the experimental group A,experimental group B and experimental group C were all decreased,the crossing circle times were also reduced.Hippocampal neuron apoptosis were(2.3±1.7)%,(14.7±6.9)%,(4.2±3.3)%,(10.2±4.8r%in control group,experimental group A,experimental group B and experimental group C,respectively.The neurons apoptosis of experimental group A was significantly increased.The serum IL-4 and 1L-10 of the experimental group A,experimental group B and experimental group C after anesthesia were significantly higher than the control group.The whole brain IL-1β of the experimental group A,experimental group B and experimental group C were significantly lower than the control group.Conclusions:Propofol can reduce anesthesia effect of ketamine on the cognitive function and immune function in the young rats.

Neuron-protective effect of subanesthestic-dosage ketamine on mice of Parkinson's disease

Objective: To discuss the neuron-protective effect and possible mechanism of subanesthestic-dosage ketamine on Parkinson's disease mice induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.Methods: A total of 30 mice were divided equally into three groups, model control group(MC group), ketamine treatment group(KT group), and blank control group(BC group), respectively.The Parkinson's disease mice of MC group and KT groups were established by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(20 mg/kg/d), while mice in KT group were treated by intraperitoneal injection of subanesthestic-dosage ketamine(8 mg/kg).Differences on behaviors and the number of nigra dopaminergic neurons of mice in each group were compared through the behavioral test and tyrosine hydroxylase immunohistochemistry experiments after the treatments.Furthermore, Western blot was used to test the expression of autophagy-related gene LC3-Ⅱ, Beclin1, Parkin, PINK1,and mTOR.Results: Compared with the BC group, the neuroethology scores were lower and the amount of TH positive cells were less both in MC and MT groups; In KT group, the neuroethology scores were higher and the amount of tyrosine hydroxylase positive cells were significantly more than that in MC group(P < 0.05).Moreover, expression levels of autophagy-related proteins LC3-II, Beclin1, Parkin, and PINK1 were higher, while the mTOR expression level was lower than that in MC group.Conclusions: The subanesthestic-dosage ketamine has some protective effects on the coordinating ability of movement and cognitive ability of Parkinson's disease mice induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.This is probably due to that the autophagy activity of cells is activated by subanesthestic-dosage ketamine and that the neurons are protected.

Neonatal ketamine exposure-induced hippocampal neuroapoptosis in the developing brain impairs adult spatial learning ability

Ketamine exposure can lead to selective neuroapoptosis in the developing brain.p66ShcA,the cellular adapter protein expressed selectively in immature neurons,is a known pro-apoptotic molecule that triggers neuroapoptosis when activated.Sprague-Dawley rats at postnatal day 7 were subcutaneously injected in the neck with ketamine 20 mg/kg,six times at 2-hour intervals.At 0,1,3,and 6 hours after final injection,western blot assay was used to detect the expression of cleaved caspase-3,p66ShcA,and phosphorylated p66ShcA.We found that the expression of activated p66ShcA and caspase-3 increased after ketamine exposure and peaked at 3 hours.The same procedure was performed on a different group of rats.At the age of 4 weeks,spatial learning and memory abilities were tested with the Morris water maze.Latency to find the hidden platform for these rats was longer than it was for control rats,although the residence time in the target quadrant was similar.These findings indicate that ketamine exposure resulted in p66ShcA being activated in the course of an apoptotic cascade during the neonatal period.This may have contributed to the deficit in spatial learning and memory that persisted into adulthood.The experimental protocol was approved by the Institutional Animal Care and Use Committee at the University of Texas at Arlington,USA (approval No.A13.008) on January 22,2013.

Effect of Preemptive Ketamine Administration on Postoperative Visceral Pain after Gynecological Laparoscopic Surgery

The pain following gynecological laparoscopic surgery is less intense than that following open surgery; however, patients often experience visceral pain after the former surgery. The aim of this study was to determine the effects of preemptive ketamine on visceral pain in patients undergoing gynecological laparoscopic surgery. Ninety patients undergoing gynecological laparoscopic surgery were randomly assigned to one of three groups. Group 1 received placebo. Group 2 was intravenously injected with preincisional saline and local infiltration with 20 m L ropivacaine（4 mg/m L） at the end of surgery. Group 3 was intravenously injected with preincisional ketamine（0.3 mg/kg） and local infiltration with 20 m L ropivacaine（4 mg/m L） at the end of surgery. A standard anesthetic was used for all patients, and meperidine was used for postoperative analgesia. The visual analogue scale（VAS） scores for incisional and visceral pain at 2, 6, 12, and 24 h, cumulative analgesic consumption and time until first analgesic medication request, and adverse effects were recorded postoperatively. The VAS scores of visceral pain in group 3 were significantly lower than those in group 2 and group 1 at 2 h and 6 h postoperatively（P〈0.05 and P〈0.01, respectively）. At 2 h and 6 h, the VAS scores of incisional pain did not differ significantly between groups 2 and 3, but they were significantly lower than those in group 1（P〈0.01）. Groups 1 and 2 did not show any differences in visceral pain scores at 2 h and 6 h postoperatively. Moreover, the three groups showed no statistically significant differences in visceral and incisional pain scores at 12 h and 24 h postoperatively. The consumption of analgesics was significantly greater in group 1 than in groups 2 and 3, and the time to first request for analgesics was significantly longer in groups 2 and 3 than in group 1, with no statistically significant difference between groups 2 and 3. However, the three groups showed no significant difference in the incidence of shoulder pain or adverse effects. Preemptive ketamine may reduce visceral pain in patients undergoing gynecological laparoscopic surgery.

Ketamine induces tau hyperphosphorylation at serine 404 in the hippocampus of neonatal rats

Male Wistar 7-day-old rats were injected with 40 mg/kg ketamine intraperitoneally, followed by three additional injections of 20 mg/kg ketamine each upon restoration of the righting reflex. Neonatal rats injected with equivalent volumes of saline served as controls. Hippocampal samples were collected at 1,7 or 14 days following administration. Electron microscopy showed that neuronal structure changed noticeably following ketamine treatment. Specifically, microtubular structure became irregular and disorganized. Quantitative real time-PCR revealed that phosphorylated tau mRNA was upregulated after ketamine. Western blot analysis demonstrated that phosphorylated tau levels at serine 396 initially decreased at 1 day after ketamine injection, and then gradually returned to control values. At 14 days after injection, levels of phosphorylated tau were higher in the ketamine group than in the control group. Tau protein phosphorylated at serine 404 significantly increased after ketamine injection and then gradually decreased with time. However, the levels of tau protein at serine 404 were significantly greater in the ketamine group than in the control group until 14 days. The present results indicate that ketamine induces an increase of phosphorylated tau mRNA and excessive phosphorylation of tau protein at serine 404, causing disruption of microtubules in the neonatal rat hippocampus and potentially resulting in damage to hippocampal neurons.

Effects of ketamine on mouse hippocampal inflammatory cytokines IL-6,IL-1β and TNF-α levels in acute and chronic administration models

OBJECTIVE Ketamine is an injectable anesthetic and recreational drug of abuse commonly used worldwide. Many experimental studies have shown that ketamine can impair cognitive function and induce psychotic states. Neuroinflammation has been suggested to play an important role in neurodegeneration. Meanwhile,ketamine has been showed to modulate the levels of inflammatory cytokines.Therefore,we sought to investigate whether the effects of ketamine on the central nervous system is associated with the inflammatory cytokines. METHODS We established acute(single or multiple intraperitoneal injection) and chronic(six months daily intraperitoneal injection) ketamine administration models in C57BL/6 mice,evaluated the spatial recognition memory and emotional response by applying the Y maze test and open field test. We analyzed the changes of inflammatory cytokines interleukin-6(IL-6),interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) levels in mouse hippocampus,employing Western blot,quantitative reverse transcriptase-polymerase chain reaction(qR T-PCR) and immunohistochemistry. RESULTS Ketamine induced spatial recognition memory deficit,reduced anxiety-like behaviors in mice after chronic administration,and it was dose-dependent. Moreover,we found that ketamine could increase the levels of mouse hippocampal inflammatory cytokines IL-6 and IL-1β after single,multiple and long-term administration in a dose-dependent manner. However,the level of TNF-α expressed differently in mouse hippocampus under different conditions. Single administration of ketamine increased the level of TNF-α,whereas multiple and long-term administration decreased it significantly. We considered that TNF-α might exist bi-directional regulatory pathway,which was associated with the dose and duration of ketamine administration. CONCLUSION Our results suggest that the alterations of inflammatory cytokines IL-6,IL-1β and TNF-α levels may be involved in the neurotoxicity of ketamine.

Use of ketamine sedation for the management of displaced paediatric forearm fractures

AIM To determine if ketamine sedation is a safe and cost effective way of treating displaced paediatric radial and ulna fractures in the emergency department. METHODS Following an agreed interdepartmental protocol, fractures of the radius and ulna(moderately to severely displaced) in children between the age of 2 and 16 years old, presenting within a specified 4 mo period, were manipulated in our paediatric emergency department. Verbal and written consent was obtained prior to procedural sedation to ensure parents were informed and satisfied to have ketamine. A single attempt at manipulation was performed. Pre and postmanipulation radiographs were requested and assessed to ensure adequacy of reduction. Parental satisfaction surveys were collected after the procedure to assess the perceived quality of treatment. After closed reduction and cast immobilisation, patients were then followed-up in the paediatric outpatient fracture clinic and functional outcomes measured prospectively. A cost analysis compared to more formal manipulation under a general anaesthetic was also undertaken.RESULTS During the 4 mo period of study, 10 closed, moderate to severely displaced fractures were identified and treated in the paediatric emergency department using our ketamine sedation protocol. These included fractures of the growth plate(3), fractures of both radius and ulna(6) and a single isolated proximal radius fracture. The mean time from administration of ketamine until completion of the moulded plaster was 20 min. The mean time interval from sedation to full recovery was 74 min. We had no cases of unacceptable fracture reduction and no patients required any further manipulation, either in fracture clinic or under a more formal general anaesthetic. There were no serious adverse events in relation to the use of ketamine. Parents, patients and clinicians reported extremely favourable outcomes using this technique. Furthermore, compared to using a manipulation under general anaesthesia, each case performed under ketamine sedation was associated with a saving of ￡1470, the overall study saving being ￡14700. CONCLUSION Ketamine procedural sedation in the paediatric population is a safe and cost effective method for the treatment of displaced fractures of the radius and ulna, with high parent satisfaction rates.

Ketamine inhibits c-Jun protein expression in mouse hippocampus following cerebral ischemia/reperfusion injury

A model of cerebral ischemia and reperfusion was established in mice.Mice were treated with ketamine via intraperitoneal injection immediately following ischemia or ischemia/reperfusion.Ketamine did not remarkably change infarct volume in mice immediately following ischemia,but injection immediately following ischemia/reperfusion significantly decreased infarct volume.Ketamine injection immediately after ischemia or ischemia/reperfusion inhibited c-Jun protein expression in mouse hippocampus,but nuclear factor kappa B expression was unaltered.In addition,the Longa scale score for neural impairment was not reduced in mice following cerebral ischemia/reperfusion.These results indicate that ketamine can protect mice against cerebral ischemia and reperfusion injury by modulating c-Jun protein expression in mouse hippocampus.

Intranasal ketamine for the treatment of patients with acute pain in the emergency department

BACKGROUND:Pain in the emergency department(ED)is common but undertreated.The objective of this study was to examine the efficacy and safety of intranasal(IN)ketamine used as an analgesic for patients with acute injury with moderate to severe pain.METHODS:This study was a cross sectional,observational study of patients more than 8 years old experiencing moderate to severe pain[visual analog score(VAS)>50 mm].The initial dose of IN ketamine was 0.7 mg/kg with an additional dose of 0.3 mg/kg if VAS was more than 50 mm after 15minutes.Pain scores and vital signs were recorded at 0,15,30 and 60 minutes.Side-effects,sedation level and patient's satisfaction were also recorded.The primary outcome was the number of patients achieving≥20 mm reductions in VAS at 15 minutes.Other secondary outcome measures were median reduction in VAS at 15,30 and 60 minutes,changes of vital signs,adverse events,satisfaction of patients,and need for additional ketamine.RESULTS:Thirty-four patients with a median age of 29.5 years(IQR 17.5–38)were enrolled,and they had an initial median VAS of 80 mm(IQR 67–90).The VAS decreased more than 20 mm at15 minutes in 27(80%)patients.The reduction of VAS from baseline to 40 mm(IQR 20–40),20 mm(IQR 14–20)and 20 mm(IQR 10–20)respectively at 15,30 and 60 minutes(P<0.001).No critical changes of vital signs were noted and adverse effects were mild and transient.CONCLUSION:This study showed that IN ketamine is an analgesic choice for patients with acute injury in moderate to severe pain in an overcrowded and resource limited ED.

Ketamine Promotes Inflammation through Increasing TLR4 Expression in RAW264.7 Cells

Ketarnine （KTM）, a N-methyl-D-aspartate （NMDA） receptor antagonist, was found to has an anti-inflammatory effect, but some patients suffered from exacerbated pro-inflammatory reactions after anesthesia with KTM. The present study was aimed to examine the underlying mechanism of pro-inflammatory effects of KTM. In this study, RAW264.7 cells were exposed to KTM and NMDA alone or combined for 30 min before lipopolysaccharide （LPS） stimulation. The expression levels of IL-6 and TNF-α were detected by RT-PCR and ELISA, and those of NMDA receptors by RT-PCR in RAW264.7 cells. Additionally, the TLR4 expression was determined by RT-PCR and flow cytometry, respectively. The results showed that in RAW264.7 cells, KTM alone promoted the TLR4 expression, but did not increase the expression of IL-6 or TNF-α. In the presence of LPS, KTM caused a signifi- cantly higher expression of IL-6 and TNF-a than LPS alone. NMDA could neither alter the IL-6 and TNF-α mRNA expression, nor reverse the enhanced expression of IL-6 and TNF-α mRNA by KTM in LPS-challenged cells. After TLR4-siRNA transfection, RAW264.7 cells pretreated with KTM no longer promoted the IL-6 and TNF-α expression in the presence of LPS. In conclusion, KTM accelerated LPS-induced inflammation in RAW264.7 cells by promoting TLR4 expression, independent of NMDA receptor.

Dexmedetomidine versus Ketamine for the Prevention of Emergence Agitation in Pediatric: A Prospective, Randomized, and Controlled Clinical Trial

Background: This study compares the effect of dexmedetomidine versus Ketamine for the prevention of emergence agitation in children undergoing general anaesthesia. Method: 75 Children are randomly allocated into three groups. Group C: Were assigned to receive normal saline. Group K: Were assigned to receive Ketamine 0.25 mg/kg. Group D: assigned to receive 0.25 ug /kg of dexmedetomidine, before the end of surgery. Results: There was no statistically significant difference in demographic data and intraoperative parameters between the three groups. But as regards to time to discharge, there was a significant difference between group C, group K and group D (group C = 39.96 ± 2.84, group K = 37.28 ± 3.80, group D = 35.08 ± 3.36 and P value = 0.0002). FLACC scale was low after extubation, before leaving the operating room and on arrival to PACU (small FLACC scale in group K, D than group C). PAED scoreless in Group K and Group D than Group C (postoperative, at 10 minutes, 20 min, 30 min). Conclusion: Ketamine and dexmedetomidine reduced the incidence and severity of emergence delirium effectively when compared to normal saline, and the effects of dexmedetomidine being much superior to Ketamine.

Ketamine and midazolam sedation for pediatric gastrointestinal endoscopy in the Arab world

AIM:To evaluate the safety and effectiveness of intravenous ketamine-midazolam sedation during pediatric endoscopy in the Arab world.METHODS:A retrospective cohort study of all pediatric endoscopic procedures performed between 2002-2008 at the shared endoscopy suite of King Abdullah University Hospital,Jordan University of Science & Technology,Jordan was conducted.All children were > 1 year old and weighed > 10 kg with American Society of Anesthesiologists class 1 or 2.Analysis was performed in terms of sedation-related complications(desaturation,respiratory distress,apnea,bradycar-dia,cardiac arrest,emergence reactions),adequacy of sedation,need for sedation reversal,or failure to complete the procedure.RESULTS:A total of 301 patients(including 160 males) with a mean age of 9.26 years(range,1-18 years) were included.All were premedicated with atropine;and 79.4%(239/301) had effective and uneventful sedation.And 248(82.4%) of the 301 patients received a mean dose of 0.16 mg/kg(range,0.07-0.39) midazolam and 1.06 mg/kg(range,0.31-2.67) ketamine,respectively within the recommended dosage guidelines.Recommended maximum midazolam dose was exceeded in 17.6% patients [34 female(F):19 male(M),P = 0.003] and ketamine in 2.7%(3 M:5 F).Maximum midazolam dose was more likely to be exceeded than ketamine(P < 0.001).Desaturation occurred in 37(12.3%) patients,and was reversible by supplemental oxygen in all except 4 who continue to have desaturation despite supplemental oxygen.Four(1.3%) patients had respiratory distress and 6(2%) were difficult to sedate and required a 3rd sedative;12(4%) required reversal and 7(2.3%) failed to complete the procedure.None developed apnea,bradycardia,arrest,or emergence reactions.CONCLUSION:Ketamine-midazolam sedation appears safe and effective for diagnostic pediatric gastrointestinal endoscopy in the Arab world for children aged > 1 year and weighing > 10 kg without co-morbidities.

Chronic lithium treatment ameliorates ketamine-induced mania-like behavior via the PI3K-AKT signaling pathway

Ketamine, a rapid-acting antidepressant drug, has been used to treat major depressive disorder and bipolar disorder(BD). Recent studies have shown that ketamine may increase the potential risk of treatment-induced mania in patients. Ketamine has also been applied to establish animal models of mania. At present, however, the underlying mechanism is still unclear. In the current study, we found that chronic lithium exposure attenuated ketamine-induced mania-like behavior and c-Fos expression in the medial prefrontal cortex(mPFC) of adult male mice. Transcriptome sequencing was performed to determine the effect of lithium administration on the transcriptome of the PFC in ketamine-treated mice, showing inactivation of the phosphoinositide 3-kinase(PI3K)-protein kinase B(AKT) signaling pathway. Pharmacological inhibition of AKT signaling by MK2206(40 mg/kg), a selective AKT inhibitor, reversed ketamine-induced mania.Furthermore, selective knockdown of AKT via AAVAKT-sh RNA-EGFP in the mPFC also reversed ketamine-induced mania-like behavior. Importantly,pharmacological activation of AKT signaling by SC79(40 mg/kg), an AKT activator, contributed to mania in low-dose ketamine-treated mice. Inhibition of PI3K signaling by LY294002(25 mg/kg), a specific PI3K inhibitor, reversed the mania-like behavior in ketamine-treated mice. However, pharmacological inhibition of mammalian target of rapamycin(mTOR)signaling with rapamycin(10 mg/kg), a specific mTOR inhibitor, had no effect on ketamine-induced mania-like behavior. These results suggest that chronic lithium treatment ameliorates ketamine-induced mania-like behavior via the PI3K-AKT signaling pathway, which may be a novel target for the development of BD treatment.

Prospective, Randomized Comparisons of Induction of Anesthesia with Ketamine, Propofol and Sevoflurane for Quality of Recovery from Short Sevoflurane Anesthesia in Pediatric Patients

Background: Emergence agitation (EA) after sevoflurane anesthesia is common in children. When rapid intravenous induction of general anesthesia is indicated in a brief procedure, the induction agent can reduce the incidence of EA after sevoflurane anesthesia. The aim of this study was to compare the efficacy of intravenous induction with ketamine and propofol for reducing EA in children after short sevoflurane anesthesia. Methods: Children aged 2 to 6 years who were scheduled to undergo inguinal hernia repair were randomly divided into 3 groups to receive 2 mg/kg ketamine iv, 3 mg/kg propofol iv, or inspired concentration of 8% sevoflurane for induction of anesthesia. After a laryngeal mask airway (LMA) insertion, a caudal block was performed in all children. Anesthesia was maintained with 1.5% sevoflurane and 65% nitrous oxide in oxygen with spontaneous ventilation. The recovery characteristics were recorded and EA were evaluated by using the Pediatric Anesthesia Emergence Delirium (PAED) scale. Results: One hundred and twenty children were enrolled and randomized to treatment. Children who received ketamine induction had higher incidence of EA than those who received propofol (42% vs 16%, P < 0.05) and showed delayed recovery (32 ± 9 min) as compared with those who received propofol or sevoflurane (22 ± 8 min and 20 ± 7 min, respectively, P < 0.05). The mean peak PAED score was significantly lower in children who received propofol induction (6.8 ± 4.0, P < 0.05) than ketamine (11.8 ± 4.1) or sevoflurane (11.6 ± 3.8). Conclusions: Intravenous induction with ketamine does not prevent the incidence of EA and delays recovery. Induction with propofol improves the quality of recovery by reducing the incidence of EA and provides a safe and early recovery.

Early and Late Postoperative Pain and Side Effects after Mastectomy: A Comparison of Ketamine and Thiamylal Administered for Anesthetic Induction

Objective: To compare acute and long-term postoperative pain and side effects in patients undergoing mastectomy for breast cancer under general anesthesia induced with ketamine or thiamylal. Methods: Twenty four ASA physical status I-III patients undergoing mastectomy were randomly assigned to one of two groups. Ketamine group received intravenous ketamine, 1 mg/kg, and thiamylal group received intravenous thiamylal, 4 mg/kg, at the induction of general anesthesia. Anesthesia was maintained with sevoflurane, N2O and fentanyl. The intensity of pain was assessed by using visual analog scale (VAS) 3 and 16 hr and 2, 3 and 4 weeks after surgery. Postoperative side effects, including nausea, vomiting and hallucination were also recorded. Results: At 16 hr after surgery, VAS in ketamine group was significantly lower than that in thiamylal group. However, there were no statistically significant differences between the two groups in the VAS at 3 hr and 2, 3 and 4 weeks after surgery. There were no differences in the incidence of side effects such as nausea, vomiting and hallucination between the two groups. Conclusion: Intravenous ketamine at the induction of anesthesia could reduce acute postoperative pain but not long-term pain after mastectomy.