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Xie Y, Zhao J, Li X, Sun J, Yang H. Effects of Cyfluthrin Exposure on Neurobehaviour, Hippocampal Tissue and Synaptic Plasticity in Wistar Rats. TOXICS 2023; 11:999. [PMID: 38133400 PMCID: PMC10748044 DOI: 10.3390/toxics11120999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023]
Abstract
This experiment was conducted to study the effects of Cyfluthrin (Cy) exposure on neurobehaviour, hippocampal tissue and synaptic plasticity in Wistar rats. First, it was found that high-dose Cy exposure could cause nerve injury, resulting in symptoms such as deficits in learning and memory ability, spatial exploration and autonomic motor function. Moreover, it was found that medium- and high-dose Cy exposure could cause an abnormal release of the neurotransmitter Glu. Second, brain tissue pathology showed that the middle and high doses of Cy caused tissue deformation, reduced the number of hippocampal puramidal cells, caused a disorder of these cells, decreased the number of Nissl bodies, and caused pyknosis of the hippocampal cell nuclear membrane and serious damage to organelles, indicating that exposure to these doses of Cy may cause hippocampal tissue damage in rats. Third, as the exposure dose increased, morphological changes in hippocampal synapses, including blurred synaptic spaces, a decreased number of synaptic vesicles and a decreased number of synapses, became more obvious. Moreover, the expression levels of the key synaptic proteins PSD-95 and SYP also decreased in a dose-dependent manner, indicating obvious synaptic damage. Finally, the study found that medium and high doses of Cy could upregulate the expression of A2AR in the hippocampus and that the expression levels of inflammatory factors and apoptosis-related proteins increased in a dose-dependent manner. Moreover, the expression of A2AR mRNA was correlated with neurobehavioural indicators and the levels of inflammatory factors, synaptic plasticity-related factors and apoptosis-related factors, suggesting that Cy may cause nerve damage in rats and that this effect is closely related to A2AR.
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Affiliation(s)
- Yongxin Xie
- School of Public Health, Ningxia Medical University, Yinchuan 750004, China; (Y.X.); (J.Z.); (X.L.)
- Key Laboratory of Environmental Factors and Chronic Disease Control, No. 1160, Shengli Street, Xingqing District, Yinchuan 750004, China
| | - Ji Zhao
- School of Public Health, Ningxia Medical University, Yinchuan 750004, China; (Y.X.); (J.Z.); (X.L.)
- Key Laboratory of Environmental Factors and Chronic Disease Control, No. 1160, Shengli Street, Xingqing District, Yinchuan 750004, China
| | - Xiaoyu Li
- School of Public Health, Ningxia Medical University, Yinchuan 750004, China; (Y.X.); (J.Z.); (X.L.)
- Key Laboratory of Environmental Factors and Chronic Disease Control, No. 1160, Shengli Street, Xingqing District, Yinchuan 750004, China
| | - Jian Sun
- School of Public Health, Ningxia Medical University, Yinchuan 750004, China; (Y.X.); (J.Z.); (X.L.)
- Key Laboratory of Environmental Factors and Chronic Disease Control, No. 1160, Shengli Street, Xingqing District, Yinchuan 750004, China
| | - Huifang Yang
- School of Public Health, Ningxia Medical University, Yinchuan 750004, China; (Y.X.); (J.Z.); (X.L.)
- Key Laboratory of Environmental Factors and Chronic Disease Control, No. 1160, Shengli Street, Xingqing District, Yinchuan 750004, China
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Early Developmental Exposure to Repetitive Long Duration of Midazolam Sedation Causes Behavioral and Synaptic Alterations in a Rodent Model of Neurodevelopment. J Neurosurg Anesthesiol 2019; 31:151-162. [PMID: 30767941 DOI: 10.1097/ana.0000000000000541] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
There is a large body of preclinical literature suggesting that exposure to general anesthetic agents during early life may have harmful effects on brain development. Patients in intensive care settings are often treated for prolonged periods with sedative medications, many of which have mechanisms of action that are similar to general anesthetics. Using in vivo studies of the mouse hippocampus and an in vitro rat cortical neuron model we asked whether there is evidence that repeated, long duration exposure to midazolam, a commonly used sedative in pediatric intensive care practice, has the potential to cause lasting harm to the developing brain. We found that mice that underwent midazolam sedation in early postnatal life exhibited deficits in the performance on Y-maze and fear-conditioning testing at young adult ages. Labeling with a nucleoside analog revealed a reduction in the rate of adult neurogenesis in the hippocampal dentate gyrus, a brain region that has been shown to be vulnerable to developmental anesthetic neurotoxicity. In addition, using immunohistochemistry for synaptic markers we found that the number of presynaptic terminals in the dentate gyrus was reduced, while the number of excitatory postsynaptic terminals was increased. These findings were replicated in a midazolam sedation exposure model in neurons in culture. We conclude that repeated, long duration exposure to midazolam during early development has the potential to result in persistent alterations in the structure and function of the brain.
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Early Developmental Exposure to General Anesthetic Agents in Primary Neuron Culture Disrupts Synapse Formation via Actions on the mTOR Pathway. Int J Mol Sci 2018; 19:ijms19082183. [PMID: 30049952 PMCID: PMC6121894 DOI: 10.3390/ijms19082183] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/18/2018] [Accepted: 07/20/2018] [Indexed: 12/05/2022] Open
Abstract
Human epidemiologic studies and laboratory investigations in animal models suggest that exposure to general anesthetic agents (GAs) have harmful effects on brain development. The mechanism underlying this putative iatrogenic condition is not clear and there are currently no accepted strategies for prophylaxis or treatment. Recent evidence suggests that anesthetics might cause persistent deficits in synaptogenesis by disrupting key events in neurodevelopment. Using an in vitro model consisting of dissociated primary cultured mouse neurons, we demonstrate abnormal pre- and post-synaptic marker expression after a clinically-relevant isoflurane anesthesia exposure is conducted during neuron development. We find that pharmacologic inhibition of the mechanistic target of rapamycin (mTOR) pathway can reverse the observed changes. Isoflurane exposure increases expression of phospho-S6, a marker of mTOR pathway activity, in a concentration-dependent fashion and this effect occurs throughout neuronal development. The mTOR 1 complex (mTORC1) and the mTOR 2 complex (mTORC2) branches of the pathway are both activated by isoflurane exposure and this is reversible with branch-specific inhibitors. Upregulation of mTOR is also seen with sevoflurane and propofol exposure, suggesting that this mechanism of developmental anesthetic neurotoxicity may occur with all the commonly used GAs in pediatric practice. We conclude that GAs disrupt the development of neurons during development by activating a well-defined neurodevelopmental disease pathway and that this phenotype can be reversed by pharmacologic inhibition.
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Maloney SE, Creeley CE, Hartman RE, Yuede CM, Zorumski CF, Jevtovic-Todorovic V, Dikranian K, Noguchi KK, Farber NB, Wozniak DF. Using animal models to evaluate the functional consequences of anesthesia during early neurodevelopment. Neurobiol Learn Mem 2018; 165:106834. [PMID: 29550366 DOI: 10.1016/j.nlm.2018.03.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 02/16/2018] [Accepted: 03/13/2018] [Indexed: 12/15/2022]
Abstract
Fifteen years ago Olney and colleagues began using animal models to evaluate the effects of anesthetic and sedative agents (ASAs) on neurodevelopment. The results from ongoing studies indicate that, under certain conditions, exposure to these drugs during development induces an acute elevated apoptotic neurodegenerative response in the brain and long-term functional impairments. These animal models have played a significant role in bringing attention to the possible adverse effects of exposing the developing brain to ASAs when few concerns had been raised previously in the medical community. The apoptotic degenerative response resulting from neonatal exposure to ASAs has been replicated in many studies in both rodents and non-human primates, suggesting that a similar effect may occur in humans. In both rodents and non-human primates, significantly increased levels of apoptotic degeneration are often associated with functional impairments later in life. However, behavioral deficits following developmental ASA exposure have not been consistently reported even when significantly elevated levels of apoptotic degeneration have been documented in animal models. In the present work, we review this literature and propose a rodent model for assessing potential functional deficits following neonatal ASA exposure with special reference to experimental design and procedural issues. Our intent is to improve test sensitivity and replicability for detecting subtle behavioral effects, and thus enhance the translational significance of ASA models.
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Affiliation(s)
- Susan E Maloney
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Intellectual and Developmental Disabilities Research Center, Washington University, St. Louis, MO, USA
| | - Catherine E Creeley
- Department of Psychology, The State University of New York at Fredonia, Fredonia, NY 14063, USA
| | - Richard E Hartman
- Department of Psychology, Loma Linda University, 11130 Anderson St., Loma Linda, CA 92354, USA
| | - Carla M Yuede
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Charles F Zorumski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Krikor Dikranian
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
| | - Kevin K Noguchi
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Intellectual and Developmental Disabilities Research Center, Washington University, St. Louis, MO, USA
| | - Nuri B Farber
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Intellectual and Developmental Disabilities Research Center, Washington University, St. Louis, MO, USA
| | - David F Wozniak
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA; Intellectual and Developmental Disabilities Research Center, Washington University, St. Louis, MO, USA.
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5
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Xie SN, Ye H, Li JF, An LX. Sevoflurane neurotoxicity in neonatal rats is related to an increase in the GABAAR α1/GABAAR α2 ratio. J Neurosci Res 2017; 95:2367-2375. [PMID: 28843008 DOI: 10.1002/jnr.24118] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 05/23/2017] [Accepted: 06/26/2017] [Indexed: 01/24/2023]
Affiliation(s)
- Si-Ning Xie
- Department of Anesthesiology, Beijing TianTan Hospital; Capital Medical University; No. 6 Tiantan Xili, Dongcheng District Beijing 100050 China
| | - Hong Ye
- Department of Anesthesiology, Beijing TianTan Hospital; Capital Medical University; No. 6 Tiantan Xili, Dongcheng District Beijing 100050 China
| | - Jun-Fa Li
- Department of Neurobiology; Capital Medical University; No. 10 Xi-Tou-Tiao, You’an Men Wai, Fengtai District Beijing 100069 China
| | - Li-Xin An
- Department of Anesthesiology, Beijing TianTan Hospital; Capital Medical University; No. 6 Tiantan Xili, Dongcheng District Beijing 100050 China
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Kang E, Jiang D, Ryu YK, Lim S, Kwak M, Gray CD, Xu M, Choi JH, Junn S, Kim J, Xu J, Schaefer M, Johns RA, Song H, Ming GL, Mintz CD. Early postnatal exposure to isoflurane causes cognitive deficits and disrupts development of newborn hippocampal neurons via activation of the mTOR pathway. PLoS Biol 2017; 15:e2001246. [PMID: 28683067 PMCID: PMC5500005 DOI: 10.1371/journal.pbio.2001246] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 06/02/2017] [Indexed: 12/18/2022] Open
Abstract
Clinical and preclinical studies indicate that early postnatal exposure to anesthetics can lead to lasting deficits in learning and other cognitive processes. The mechanism underlying this phenomenon has not been clarified and there is no treatment currently available. Recent evidence suggests that anesthetics might cause persistent deficits in cognitive function by disrupting key events in brain development. The hippocampus, a brain region that is critical for learning and memory, contains a large number of neurons that develop in the early postnatal period, which are thus vulnerable to perturbation by anesthetic exposure. Using an in vivo mouse model we demonstrate abnormal development of dendrite arbors and dendritic spines in newly generated dentate gyrus granule cell neurons of the hippocampus after a clinically relevant isoflurane anesthesia exposure conducted at an early postnatal age. Furthermore, we find that isoflurane causes a sustained increase in activity in the mechanistic target of rapamycin pathway, and that inhibition of this pathway with rapamycin not only reverses the observed changes in neuronal development, but also substantially improves performance on behavioral tasks of spatial learning and memory that are impaired by isoflurane exposure. We conclude that isoflurane disrupts the development of hippocampal neurons generated in the early postnatal period by activating a well-defined neurodevelopmental disease pathway and that this phenotype can be reversed by pharmacologic inhibition. The United States Food and Drug Administration has recently warned that exposure to anesthetic and sedative drugs during the third trimester of prenatal development and during the first 3 years of life may cause lasting impairments in cognitive function. The mechanisms by which this undesirable side effect occurs are unknown. In this manuscript, we present evidence in mice that early developmental exposure to isoflurane, a canonical general anesthetic, disrupts the appropriate development of neurons in the hippocampus, a brain region associated with learning and memory. Isoflurane also causes up-regulation of the mechanistic target of rapamycin (mTOR) pathway, a signaling system that has been associated with other neurodevelopmental cognitive disorders. Treatment with an inhibitor of the mTOR pathway after isoflurane exposure normalizes neuronal development and also ameliorates the impairments in learning induced by isoflurane. We conclude that early exposure to isoflurane can cause learning deficits via actions on the mTOR pathway, and that this mechanism represents a potentially druggable target to minimize the side effects of anesthetics on the developing brain.
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Affiliation(s)
- Eunchai Kang
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Danye Jiang
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Yun Kyoung Ryu
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sanghee Lim
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Minhye Kwak
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Christy D. Gray
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Michael Xu
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jun H. Choi
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sue Junn
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jieun Kim
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jing Xu
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Michele Schaefer
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Roger A. Johns
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Hongjun Song
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- The Solomon Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Guo-Li Ming
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- The Solomon Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - C. David Mintz
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Li X, Lu F, Li W, Xu J, Sun XJ, Qin LZ, Zhang QL, Yao Y, Yu QK, Liang XL. Underlying Mechanisms of Memory Deficits Induced by Etomidate Anesthesia in Aged Rat Model: Critical Role of Immediate Early Genes. Chin Med J (Engl) 2017; 129:48-53. [PMID: 26712432 PMCID: PMC4797542 DOI: 10.4103/0366-6999.172570] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background: Etomidate (R-1-[1-ethylphenyl] imidazole-5-ethyl ester) is a widely used anesthetic drug that had been reported to contribute to cognitive deficits after general surgery. However, its underlying mechanisms have not been fully elucidated. In this study, we aimed to explore the neurobiological mechanisms of cognitive impairments that caused by etomidate. Methods: A total of 30 Sprague-Dawley rats were used and divided into two groups randomly to receive a single injection of etomidate or vehicle. Then, the rats’ spatial memory ability and neuronal survival were evaluated using the Morris water maze test and Nissl staining, respectively. Furthermore, we analyzed levels of oxidative stress, as well as cyclic adenosine 3’,5’-monophosphate response element-binding (CREB) protein phosphorylation and immediate early gene (IEG, including Arc, c-fos, and Egr1) expression levels using Western blot analysis. Results: Compared with vehicle-treated rats, the etomidate-treated rats displayed impaired spatial learning (day 4: 27.26 ± 5.33 s vs. 35.52 ± 3.88 s, t = 2.988, P = 0.0068; day 5: 15.84 ± 4.02 s vs. 30.67 ± 4.23 s, t = 3.013, P = 0.0057; day 6: 9.47 ± 2.35 s vs. 25.66 ± 4.16 s, t = 3.567, P = 0.0036) and memory ability (crossing times: 4.40 ± 1.18 vs. 2.06 ± 0.80, t = 2.896, P = 0.0072; duration: 34.00 ± 4.24 s vs. 18.07 ± 4.79 s, t = 3.023, P = 0.0053; total swimming distance: 40.73 ± 3.45 cm vs. 27.40 ± 6.56 cm, t = 2.798, P = 0.0086) but no neuronal death. Furthermore, etomidate did not cause oxidative stress or deficits in CREB phosphorylation. The levels of multiple IEGs (Arc: vehicle treated rats 100%, etomidate treated rats 86%, t = 2.876, P = 0.0086; c-fos: Vehicle treated rats 100%, etomidate treated rats 72%, t = 2.996, P = 0.0076; Egr1: Vehicle treated rats 100%, etomidate treated rats 58%, t = 3.011, P = 0.0057) were significantly reduced in hippocampi of etomidate-treated rats. Conclusion: Our data suggested that etomidate might induce memory impairment in rats via inhibition of IEG expression.
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Affiliation(s)
- Xu Li
- Department of Pathology, Affiliated Cancer Hospital of Zhengzhou University, Henan Provincial Cancer Hospital, Zhengzhou, Henan 450008, China
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8
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Kang E, Berg DA, Furmanski O, Jackson WM, Ryu YK, Gray CD, Mintz CD. Neurogenesis and developmental anesthetic neurotoxicity. Neurotoxicol Teratol 2016; 60:33-39. [PMID: 27751818 DOI: 10.1016/j.ntt.2016.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/05/2016] [Accepted: 10/07/2016] [Indexed: 11/24/2022]
Abstract
The mechanism by which anesthetics might act on the developing brain in order to cause long term deficits remains incompletely understood. The hippocampus has been identified as a structure that is likely to be involved, as rodent models show numerous deficits in behavioral tasks of learning that are hippocampal-dependent. The hippocampus is an unusual structure in that it is the site of large amounts of neurogenesis postnatally, particularly in the first year of life in humans, and these newly generated neurons are critical to the function of this structure. Intriguingly, neurogenesis is a major developmental event that occurs during postulated windows of vulnerability to developmental anesthetic neurotoxicity across the different species in which it has been studied. In this review, we examine the evidence for anesthetic effects on neurogenesis in the early postnatal period and ask whether neurogenesis should be studied further as a putative mechanism of injury. Multiple anesthetics are considered, and both in vivo and in vitro work is presented. While there is abundant evidence that anesthetics act to suppress neurogenesis at several different phases, evidence of a causal link between these effects and any change in learning behavior remains elusive.
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Affiliation(s)
- Eunchai Kang
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Daniel A Berg
- Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Orion Furmanski
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - William M Jackson
- Department of Anesthesiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Yun Kyoung Ryu
- School of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Christy D Gray
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - C David Mintz
- Department of Anesthesiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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9
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Long-lasting behavioral effects in neonatal mice with multiple exposures to ketamine-xylazine anesthesia. Neurotoxicol Teratol 2016; 60:75-81. [PMID: 27622724 DOI: 10.1016/j.ntt.2016.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/03/2016] [Accepted: 09/06/2016] [Indexed: 11/20/2022]
Abstract
Anesthetic agents are often administered in the neonatal period, a time of rapid brain development and synaptogenesis. Mounting evidence suggests that anesthetics can disrupt neurocognitive development, particularly in cases of multiple or prolonged anesthetic exposure. Previous studies have shown that administering multiple doses of ketamine-xylazine (KX) anesthesia to neonatal mice can induce long-term changes to synaptic plasticity in the cortex, but the effect on neurocognitive function remains unclear. In this study, we exposed neonatal mice to single dose and multiple doses of KX anesthesia in the neonatal period (postnatal days 7, 9, 11), and conducted a series of behavioral tests in young adulthood (1month of age). Mice receiving multiple doses of KX anesthesia showed deficits in novel object recognition, sociability, preference for social novelty and contextual fear response, but no effect on auditory-cued fear response. Single dose of KX anesthesia had no effect on these behaviors except for contextual fear response. We also observed that multiple exposures to KX anesthesia were associated with decreased CaMKII phosphorylation, which is known to play a role in synapse development and long-term potentiation, likely contributing to learning impairment.
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Armstrong R, Xu F, Arora A, Rasic N, Syed NI. General anesthetics and cytotoxicity: possible implications for brain health. Drug Chem Toxicol 2016; 40:241-249. [PMID: 27252089 DOI: 10.1080/01480545.2016.1188306] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND The search for agents that bring about faster induction and quicker recovery in the operating room have yielded numerous anesthetics whose mechanisms of action and potential toxic side effects remain unknown, especially in the young and aging brain. OBJECTIVE Taking advantage of our clinical and basic science expertise, here we subject the reader to an interesting perspective vis-à-vis the current applications of general anesthetics, and present evidence for their neurotoxic effects on the developing and elderly brains. RESULTS Recent studies have called into question the safety of general anesthetics, especially with regards to potentially significant detrimental impacts on the developing brains of young children, and cognitive decline in the elderly - often following multiple episodes of anesthesia. Despite accumulating evidence from animal studies demonstrating that general anesthesia leads to neurodegeneration and cognitive impairment, to date a clear consensus on the impact of anesthetics in humans remains elusive. Because a direct impact of anesthetics on human neuronal networks is often difficult to deduce experimentally, most laboratories have resorted to animal models - albeit with limited success in translating these findings back to the clinic. Moreover, the precise mechanisms that lead to potential cognitive, learning, and memory decline in young and elderly patients also remain to be fully defined. CONCLUSIONS This review will focus primarily on the cytotoxic effects of anesthetics, and offer some practical resolutions that may attenuate their long-term harm. An urgent need for studies on animal models and an increased focus on highly controlled prospective epidemiological studies is also reinforced.
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Affiliation(s)
- Ryden Armstrong
- a The Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary , Calgary , Alberta , Canada
| | - Fenglian Xu
- a The Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary , Calgary , Alberta , Canada.,b Department of Biology , Saint Louis University , Saint Louis , MO , USA , and
| | - Anish Arora
- a The Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary , Calgary , Alberta , Canada
| | - Nivez Rasic
- c Pediatric Anesthesia and Pain Medicine, Alberta Children's Hospital , Calgary , Alberta , Canada
| | - Naweed I Syed
- a The Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary , Calgary , Alberta , Canada
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11
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Liebert AD, Chow RT, Bicknell BT, Varigos E. Neuroprotective Effects Against POCD by Photobiomodulation: Evidence from Assembly/Disassembly of the Cytoskeleton. J Exp Neurosci 2016; 10:1-19. [PMID: 26848276 PMCID: PMC4737522 DOI: 10.4137/jen.s33444] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/09/2015] [Accepted: 12/15/2015] [Indexed: 02/07/2023] Open
Abstract
Postoperative cognitive dysfunction (POCD) is a decline in memory following anaesthesia and surgery in elderly patients. While often reversible, it consumes medical resources, compromises patient well-being, and possibly accelerates progression into Alzheimer's disease. Anesthetics have been implicated in POCD, as has neuroinflammation, as indicated by cytokine inflammatory markers. Photobiomodulation (PBM) is an effective treatment for a number of conditions, including inflammation. PBM also has a direct effect on microtubule disassembly in neurons with the formation of small, reversible varicosities, which cause neural blockade and alleviation of pain symptoms. This mimics endogenously formed varicosities that are neuroprotective against damage, toxins, and the formation of larger, destructive varicosities and focal swellings. It is proposed that PBM may be effective as a preconditioning treatment against POCD; similar to the PBM treatment, protective and abscopal effects that have been demonstrated in experimental models of macular degeneration, neurological, and cardiac conditions.
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Affiliation(s)
| | - Roberta T. Chow
- Brain and Mind Institute, University of Sydney, Sydney, NSW, Australia
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12
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Korpi ER, den Hollander B, Farooq U, Vashchinkina E, Rajkumar R, Nutt DJ, Hyytiä P, Dawe GS. Mechanisms of Action and Persistent Neuroplasticity by Drugs of Abuse. Pharmacol Rev 2015; 67:872-1004. [DOI: 10.1124/pr.115.010967] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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13
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Bajwa SJS, Anand S, Gupta H. Perils of paediatric anaesthesia and novel molecular approaches: An evidence-based review. Indian J Anaesth 2015; 59:272-81. [PMID: 26019351 PMCID: PMC4445148 DOI: 10.4103/0019-5049.156865] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Evolution of anaesthesia has been largely helped by progress of evidence-based medicine. In spite of many advancements in anaesthesia techniques and availability of newer and safer drugs, much more needs to be explored scientifically for the development of anaesthesia. Over the last few years, the notion that the actions of the anaesthesiologist have only immediate or short-term consequences has largely been challenged. Evidences accumulated in the recent years have shown that anaesthesia exposure may have long-term consequences particularly in the extremes of ages. However, most of the studies conducted so far are in vitro or animal studies, the results of which have been extrapolated to humans. There have been confounding evidences linking anaesthesia exposure in the developing brain with poor neurocognitive outcome. The results of animal studies and human retrospective studies have raised concern over the potential detrimental effects of general anaesthetics on the developing brain. The purpose of this review is to highlight the long-term perils of anaesthesia in the very young and the potential of improving anaesthesia delivery with the novel molecular approaches.
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Affiliation(s)
- Sukhminder Jit Singh Bajwa
- Department of Anaesthesiology and Intensive Care, Gian Sagar Medical College and Hospital, Banur, Punjab, India
| | - Smriti Anand
- Department of Anaesthesiology and Intensive Care, Maharishi Markendeshwar Medical College and Hospital, Kumarhatti, Solan, Himachal Pradesh, India
| | - Hemant Gupta
- Department of Paediatrics, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India
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14
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Abstract
The results of several retrospective clinical studies suggest that exposure to anesthetic agents early in life is correlated with subsequent learning and behavioral disorders. Although ongoing prospective clinical trials may help to clarify this association, they remain confounded by numerous factors. Thus, some of the most compelling data supporting the hypothesis that a relatively short anesthetic exposure can lead to a long-lasting change in brain function are derived from animal models. The mechanism by which such changes could occur remains incompletely understood. Early studies identified anesthetic-induced neuronal apoptosis as a possible mechanism of injury, and more recent work suggests that anesthetics may interfere with several critical processes in brain development. The function of the mature brain requires the presence of circuits, established during development, which perform the computations underlying learning and cognition. In this review, we examine the mechanisms by which anesthetics could disrupt brain circuit formation, including effects on neuronal survival and neurogenesis, neurite growth and guidance, formation of synapses, and function of supporting cells. There is evidence that anesthetics can disrupt aspects of all of these processes, and further research is required to elucidate which are most relevant to pediatric anesthetic neurotoxicity.
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15
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Levin ED. Learning about cognition risk with the radial-arm maze in the developmental neurotoxicology battery. Neurotoxicol Teratol 2015; 52:88-92. [PMID: 26013674 DOI: 10.1016/j.ntt.2015.05.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 04/21/2015] [Accepted: 05/18/2015] [Indexed: 10/23/2022]
Abstract
Cognitive dysfunction has been found in epidemiological studies to be among the most sensitive impairments associated with developmental exposure to a variety of environmental contaminants from heavy metals to polyhalogenated hydrocarbons and pesticides. These chemicals have been also shown to impair cognitive function after developmental exposure in experimental animal models. The radial-arm maze (RAM) has proven to be a sensitive and reliable way to assess both learning and memory in a variety of species, most often in rats and mice. The RAM is a very adaptable test method that takes advantage of rodents' instinct to explore new places in the environment to forage. That is, rodents do not need to be trained to run through the maze; they will normally do this from the initial session of testing. Training with differential reinforcement for arm choices provides a more rigorous test of learning and memory. The RAM is quite adaptable for assessing various aspects of cognition. Although the RAM has been mostly used to assess spatial learning and memory, it can be configured to assess non-spatial memory as well. Both working and reference memory can be easily distinguished. The RAM can be run with both appetitive (food reinforced) and aversive (water escape) motivators. The RAM has been found to be sensitive to a wide variety of developmental toxicants including heavy metals such as mercury and pesticides such as chlorpyrifos. There is an extremely rich literature especially with rats showing the effects of many types of brain lesions and drug effects so that the participation of a wide variety of neural systems in RAM performance is known. These systems, notably the hippocampus and frontal cortex, and acetylcholine and glutamate neurotransmitter systems, are the same neural systems that have been shown in humans to be critical for learning and memory. This considerably aids the interpretation of neurobehavioral toxicity studies.
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Affiliation(s)
- Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, USA.
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16
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Murphy KL, Baxter MG. Long-term effects of neonatal single or multiple isoflurane exposures on spatial memory in rats. Front Neurol 2013; 4:87. [PMID: 23847588 PMCID: PMC3703565 DOI: 10.3389/fneur.2013.00087] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 06/20/2013] [Indexed: 11/27/2022] Open
Abstract
General anesthetics are neurotoxic to neonatal rodents and non-human primates. Neonatal exposure to general anesthetics has been associated with long-term cognitive deficits in animal models. Some data from humans are consistent with long-term deleterious effects of anesthetic exposure early in life on cognitive development, with multiple exposures to general anesthetics being particularly damaging. We sought to determine whether repeated exposure of neonatal rats to anesthesia was associated with long-term cognitive impairments and whether the magnitude of impairments was greater than that resulting from a single exposure. Male or female Long–Evans rat pups were exposed to 1.8% isoflurane for 2 h on postnatal day (P) 7, or for 2 h each on P7, P10, and P13. Testing in a spatial working memory task began on P91. Rats that were repeatedly exposed to isoflurane were impaired relative to controls in the spatial working memory task. Male rats that received a single exposure to isoflurane showed an unexpected facilitation in spatial memory performance. These results support the hypothesis that multiple neonatal exposures to general anesthesia are associated with greater long-term cognitive impairment than a single exposure. The findings are congruent with human epidemiological studies reporting long-term cognitive impairments following multiple but not single general anesthetics early in life.
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Affiliation(s)
- Kathy L Murphy
- Department of Experimental Psychology, University of Oxford , Oxford , UK ; Glickenhaus Laboratory of Neuropsychology, Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai , New York, NY , USA
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17
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Abstract
Numerous studies from the clinical and preclinical literature indicate that general anesthetic agents have toxic effects on the developing brain, but the mechanism of this toxicity is still unknown. Previous studies have focused on the effects of anesthetics on cell survival, dendrite elaboration, and synapse formation, but little attention has been paid to possible effects of anesthetics on the developing axon. Using dissociated mouse cortical neurons in culture, we found that isoflurane delays the acquisition of neuronal polarity by interfering with axon specification. The magnitude of this effect is dependent on isoflurane concentration and exposure time over clinically relevant ranges, and it is neither a precursor to nor the result of neuronal cell death. Propofol also seems to interfere with the acquisition of neuronal polarity, but the mechanism does not require activity at GABAA receptors. Rather, the delay in axon specification likely results from a slowing of the extension of prepolarized neurites. The effect is not unique to isoflurane as propofol also seems to interfere with the acquisition of neuronal polarity. These findings demonstrate that anesthetics may interfere with brain development through effects on axon growth and specification, thus introducing a new potential target in the search for mechanisms of pediatric anesthetic neurotoxicity.
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Wong TKM. Anesthesia for special needs--small infants. ACTA ANAESTHESIOLOGICA TAIWANICA : OFFICIAL JOURNAL OF THE TAIWAN SOCIETY OF ANESTHESIOLOGISTS 2012; 50:89-91. [PMID: 23026165 DOI: 10.1016/j.aat.2012.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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19
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Isoflurane protects against human endothelial cell apoptosis by inducing sphingosine kinase-1 via ERK MAPK. Int J Mol Sci 2012; 13:977-993. [PMID: 22312298 PMCID: PMC3269732 DOI: 10.3390/ijms13010977] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 01/11/2012] [Accepted: 01/12/2012] [Indexed: 12/13/2022] Open
Abstract
Endothelial dysfunction is a major clinical problem affecting virtually every patient requiring critical care. Volatile anesthetics are frequently used during the perioperative period and protect the heart and kidney against ischemia and reperfusion injury. We aimed to determine whether isoflurane, the most commonly used volatile anesthetic in the USA, protects against endothelial apoptosis and necrosis and the mechanisms involved in this protection. Human endothelial EA.hy926 cells were pretreated with isoflurane or carrier gas (95% room air + 5% CO2) then subjected to apoptosis with tumor necrosis factor-α or to necrosis with hydrogen peroxide. DNA laddering and in situ Terminal Deoxynucleotidyl Transferase Biotin-dUTP Nick-End Labeling (TUNEL) staining determined EA.hy926 cell apoptosis and percent LDH released determined necrosis. We also determined whether isoflurane modulates the expression and activity of sphingosine kinase-1 (SK1) and induces the phosphorylation of extracellular signal regulated kinase (ERK MAPK) as both enzymes are known to protect against cell death. Isoflurane pretreatment significantly decreased apoptosis in EA.hy926 cells as evidenced by reduced TUNEL staining and DNA laddering without affecting necrosis. Mechanistically, isoflurane induces the phosphorylation of ERK MAPK and increased SK1 expression and activity in EA.hy926 cells. Finally, selective blockade of SK1 (with SKI-II) or S1P1 receptor (with W146) abolished the anti-apoptotic effects of isoflurane. Taken together, we demonstrate that isoflurane, in addition to its potent analgesic and anesthetic properties, protects against endothelial apoptosis most likely via SK1 and ERK MAPK activation. Our findings have significant clinical implication for protection of endothelial cells during the perioperative period and patients requiring critical care.
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20
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Update on neonatal anesthetic neurotoxicity: insight into molecular mechanisms and relevance to humans. Anesthesiology 2009; 110:703-8. [PMID: 19276968 DOI: 10.1097/aln.0b013e31819c42a4] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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21
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Bejat G, Yao D, Hu J, Murray G, Sessle B. Effects of noxious stimulation of orofacial tissues on rat licking behaviour. Arch Oral Biol 2008; 53:361-8. [DOI: 10.1016/j.archoralbio.2007.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 09/21/2007] [Accepted: 09/28/2007] [Indexed: 10/22/2022]
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Culley DJ, Xie Z, Crosby G. General anesthetic-induced neurotoxicity: an emerging problem for the young and old? Curr Opin Anaesthesiol 2008; 20:408-13. [PMID: 17873593 DOI: 10.1097/aco.0b013e3282efd18b] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW A growing body of evidence from cells, rodents, and sub-human primates suggests that general anesthetics can be neurotoxic to the developing and senescent brain. We review this evidence and put the studies into perspective for the practicing clinician. RECENT FINDINGS Studies indicate that a variety of general anesthetics, which act primarily as gamma-amino-butyric acid receptor modulators and N-methyl-D-aspartic acid glutamate receptor antagonists, produce apoptotic neurodegeneration in the developing rodent and nonhuman primate brain. Vulnerability to this neurotoxicity is greatest during the period of synaptogenesis and presumably reflects disruption of the normal balance between excitation and inhibition during a critical period of brain development. Moreover, in the rodent, the neurodegeneration is associated with cognitive impairment into adulthood. Recent data also reveal that general anesthesia produces enduring cognitive impairment in aged but not young rodents and that halothane and isoflurane increase the generation and toxicity of amyloid beta, a protein strongly implicated in the pathogenesis of Alzheimer's disease. The meaning of these experimental results for human surgical patients is unclear, however, because human studies are lacking. SUMMARY General anesthetics produce neurotoxicity and enduring cognitive impairment in young and aged animals but it is premature to change clinical practice because the issue has not been adequately studied in humans.
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Affiliation(s)
- Deborah J Culley
- Department of Anesthesia, Brigham & Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
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Gascon E, Klauser P, Kiss JZ, Vutskits L. Potentially toxic effects of anaesthetics on the developing central nervous system. Eur J Anaesthesiol 2007; 24:213-24. [PMID: 17261215 DOI: 10.1017/s0265021506002365] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2006] [Indexed: 12/13/2022]
Abstract
A growing body of experimental evidence suggests that anaesthetics, by influencing GABAergic and glutaminergic neural signalling, can have adverse effects on the developing central nervous system. The biological foundation for this is that gamma-aminobutyric acid and glutamate could act non-synaptically, in addition to their role in neurotransmission in the adult brain, in the regulation of neuronal development in the central nervous system. These neurotransmitters and their receptors are expressed from very early stages of central nervous system development and appear to influence neural progenitor proliferation, cell migration and neuronal differentiation. During the synaptogenetic period, pharmacological blockade of N-methyl-d-aspartate (NMDA)-type glutamate receptors as well as stimulation of GABAA receptors has been reported to be associated with increased apoptosis in the developing brain. Importantly, recent data suggest that even low, non-apoptogenic concentrations of anaesthetics can perturb neuronal dendritic development and thus could potentially lead to impairment of developing neuronal networks. The extrapolation of these experimental observations to clinical practice is of course very difficult and requires extreme caution as differences in drug concentrations and exposure times as well as interspecies variations are all important confounding variables. While clinicians should clearly not withhold anaesthesia based on current animal studies, these observations should urge more laboratory and clinical research to further elucidate this issue.
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Affiliation(s)
- E Gascon
- University of Geneva Medical School, Department of Anesthesiology, Pharmacology and Intensive Care, Geneva, Switzerland
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Slotkin TA, Tate CA, Cousins MM, Seidler FJ. Prenatal nicotine exposure alters the responses to subsequent nicotine administration and withdrawal in adolescence: Serotonin receptors and cell signaling. Neuropsychopharmacology 2006; 31:2462-75. [PMID: 16341021 DOI: 10.1038/sj.npp.1300988] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Offspring of women who smoke during pregnancy are themselves more likely to take up smoking in adolescence, effects that are associated with a high rate of depression and increased sensitivity to withdrawal symptoms. To evaluate the biological basis for this relationship, we assessed effects on serotonin (5-hydroxytryptamine, 5HT) receptors and 5HT-mediated cellular responses in rats exposed to nicotine throughout prenatal development and then given nicotine in adolescence (postnatal days PN30-47.5), using regimens that reproduce plasma nicotine levels found in smokers. Evaluations were then made during the period of adolescent nicotine treatment and for up to one month after the end of treatment. Prenatal nicotine exposure, which elicits damage to 5HT projections in the cerebral cortex and striatum, produced sex-selective changes in the expression of 5HT(1A) and 5HT2 receptors, along with induction of adenylyl cyclase (AC), leading to sensitization of heterologous inputs operating through this signaling pathway. Superimposed on these effects, the AC response to 5HT was shifted toward inhibition. By itself, adolescent nicotine administration, which damages the same pathways, produced similar effects on receptors and the 5HT-mediated response, but a smaller overall induction of AC. Animals exposed to prenatal nicotine showed a reduced response to nicotine administered in adolescence, results in keeping with earlier findings of persistent desensitization. Our results indicate that prenatal nicotine exposure alters parameters of 5HT synaptic communication lasting into adolescence and changes the response to nicotine administration and withdrawal in adolescence, actions which may contribute to a subpopulation especially vulnerable to nicotine dependence.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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26
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Halm MP, Poquin D, Lestaevel P, Chancerelle Y, Graff C. Brain and cognitive impairments from burn injury in rats. Burns 2006; 32:570-6. [PMID: 16713682 DOI: 10.1016/j.burns.2005.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Accepted: 12/12/2005] [Indexed: 11/23/2022]
Abstract
Severe burn injuries affect not only the release of stress hormones but also the metabolism of nitric oxide (NO), a substance playing a large role in cognition. We investigated the effect of third-degree burns both on central NO-levels and on short-term memory in rats. Burns were administered under halothane-anesthesia by dipping 20% of the skin area in hot water. In a first experiment, NO-changes were estimated over hours by differential normal pulse voltammetry (DPNV) with a sensor implanted chronically in the frontal cortex. In a second experiment, cognitive abilities were tested over days by comparing the spontaneous time used to explore objects that the animals had, either never- or already-encountered before. Cerebral NO appeared steadily depleted for at least 12h after the injury, not after control anesthesia. During nine days following the burn, discrimination performance was lower compared to controls. Putting together the results of the two experiments, especially on the day of burn, NO changes are likely to account for the behavioral effect. A choice of neuro-pharmacological agents involved in NO-metabolism, together with a choice of proper anesthetics, should now be tested as means to alleviate cognitive impairments following third-degree burns.
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Affiliation(s)
- Marie-Pierre Halm
- Laboratoire de Biologie du Comportement, UFR SHS, Université Pierre Mendès France, BP47, 38040 Grenoble Cedex 9, France.
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27
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Vutskits L, Gascon E, Tassonyi E, Kiss JZ. Effect of Ketamine on Dendritic Arbor Development and Survival of Immature GABAergic Neurons In Vitro. Toxicol Sci 2006; 91:540-9. [PMID: 16581949 DOI: 10.1093/toxsci/kfj180] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ketamine, a noncompetitive antagonist of the N-methyl-D-aspartate type of glutamate receptors, was reported to induce neuronal cell death when administered to produce anesthesia in young rodents and monkeys. Subanesthetic doses of ketamine, as adjuvant to postoperative sedation and pain control, are also frequently administered to young children. However, the effects of these low concentrations of ketamine on neuronal development remain unknown. The present study was designed to evaluate the effects of increasing concentrations (0.01-40 microg/ml) and durations (1-96 h) of ketamine exposure on the differentiation and survival of immature gamma-aminobutyric acidergic (GABAergic) interneurons in culture. In line with previous studies (Scallet et al., 2004), we found that a 1-h-long exposure to ketamine at concentrations > or = 10 microg/ml was sufficient to trigger cell death. At lower concentrations of ketamine, cell loss was only observed when this drug was chronically (> 48 h) present in the culture medium. Most importantly, we found that a single episode of 4-h-long treatment with 5 microg/ml ketamine induced long-term alterations in dendritic growth, including a significant (p < 0.05) reduction in total dendritic length and in the number of branching points compared to control groups. Finally, long-term exposure (> 24 h) of neurons to ketamine at concentrations as low as 0.01 microg/ml also severely impaired dendritic arbor development. These results suggest that, in addition to its dose-dependent ability to induce cell death, even very low concentrations of ketamine could interfere with dendritic arbor development of immature GABAergic neurons and thus could potentially interfere with the development neural networks.
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Affiliation(s)
- Laszlo Vutskits
- Department of Anesthesiology, Pharmacology and Intensive Care, University Hospital of Geneva, 1211 Geneva 14, Switzerland.
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28
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Culley DJ, Baxter M, Yukhananov R, Crosby G. The memory effects of general anesthesia persist for weeks in young and aged rats. Anesth Analg 2003; 96:1004-1009. [PMID: 12651650 DOI: 10.1213/01.ane.0000052712.67573.12] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
UNLABELLED Studies demonstrate lasting cognitive impairment in elderly persons after anesthesia and surgery. We tested the hypothesis that general anesthesia contributes to this cognitive impairment. Six- and 18-mo-old Fischer 344 rats were trained in a 12-arm radial arm maze and were then randomized to anesthesia for 2 h with 1.2% isoflurane/70% nitrous oxide/30% oxygen or a control treatment consisting of 30% oxygen. Rats recovered for 24 h and then were tested daily on the radial arm maze for 8 wk. Performance of young control rats was stable throughout the experiment. In contrast, aged control rats improved their performance as measured by time to complete the maze but not by error rate. After anesthesia, time to complete the maze did not change in young rats, but error rate decreased (P < 0.05 at 1 and 3 wk), indicating improved performance. In contrast, previously anesthetized aged rats failed to improve with repeated testing and took longer to complete the maze than aged control rats (P < 0.05 at 1 and 3 wk). These data demonstrate that general anesthesia with isoflurane and nitrous oxide improves the memory performance on an established spatial memory task in young rats, but in aged rats it attenuates the improvement in performance that otherwise occurs with repeated testing. Therefore, isoflurane and nitrous oxide anesthesia produces a sustained learning impairment in aged rats. IMPLICATIONS This study demonstrates that general anesthesia with isoflurane and nitrous oxide improves spatial memory in young rats but impairs it in aged rats for at least 3 wk, indicating that it can influence memory for much longer than previously recognized and may adversely affect memory processes in the aged.
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Affiliation(s)
- Deborah J Culley
- *Department of Anesthesia, Harvard Medical School, Brigham & Women's Hospital, Boston, Massachusetts; and †Department of Psychology, Harvard University, Cambridge, Massachusetts
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Gotts JE, Press C, Leasure JL, Schallert T. Focal brain injury, FGF-2 and the adverse effects of excessive motor demand on cortical and nigral degeneration: marked protection by delayed intermittent exposure to halothane. J Neurotrauma 2000; 17:1067-77. [PMID: 11101209 DOI: 10.1089/neu.2000.17.1067] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The neuroprotective potential of halothane anesthesia was investigated following unilateral electrolytic lesions to the forelimb representation area of the sensorimotor cortex (FL-SMC). Previously, it was found that the FL-SMC lesion increases substantially in size when the intact forelimb is immobilized with a plaster of paris cast for the first 7 days postlesion, which forces extreme overuse of the impaired forelimb during a time when nonlethally damaged tissue is vulnerable to behavioral demand. Initially, the purpose of this study was to investigate whether intracisternal infusion of basic fibroblast growth factor (bFGF or FGF-2), a potent neurotrophic factor that has been shown to have neuroprotective and plasticity promoting properties in focal stroke and other injury models, could prevent this use-dependent exaggeration of injury. Although intracisternal bFGF (starting 24 h after surgery, twice per week) was not found to produce significant neuroprotective or behavioral effects, the brief exposure to halothane anesthesia (15-20 min) during bFGF or vehicle administration was found to prevent expansion of the lesion size, and to reduce delayed loss of neurons in the substantia nigra pars reticulata (SNr). The data have implications for investigations of the effects of neurotrophic factor in vivo, and other investigations requiring brief, intermittent halothane anesthesia.
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Affiliation(s)
- J E Gotts
- Department of Psychology and Institute for Neuroscience, University of Texas at Austin, USA
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Beck T, Weber M, Horváth E, Wree A. Functional cerebral activity during regeneration from entorhinal lesions in the rat. J Cereb Blood Flow Metab 1996; 16:342-52. [PMID: 8594068 DOI: 10.1097/00004647-199603000-00021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The consequences of an unilateral electrolytic entorhinal lesion on the functional activity in all major anatomically defined brain regions were evaluated in the rat. The 14C-2 deoxyglucose method served as a tool to quantify alterations of local cerebral glucose utilization (LCGU) ipsilateral and contralateral to the lesion at 4 days, 2 weeks, or 3 months after stereotaxic surgery. Apart from a few minor increases in the contralateral hemisphere, the predominant pattern consisted of reductions in the range of 10-40% in the ipsilateral hemisphere. Ipsilaterally, in extrahippocampal areas, LCGU had regained control levels at 2 weeks postlesion in contrast to hippocampal regions, where reductions were more pronounced than in other brain areas and partially persisted for up to 3 months. Interestingly, the termination zones of entorhinal fibers in the dentate gyrus did not regain control levels within 3 months. We conclude from the data that functional recovery of denervated primary target areas does not occur within 3 months after entorhinal lesions and that altered functional activity may be found beyond the primary target areas predominantly during the acute recovery period after the lesion. The data suggest that sprouting fibers do not reestablish a fully functional neuronal network during the recovery period.
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Affiliation(s)
- T Beck
- Anatomisches Institut der Universität Rostock, Germany
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