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Wilkes BJ, Adury RZ, Berryman D, Concepcion LR, Liu Y, Yokoi F, Maugee C, Li Y, Vaillancourt DE. Cell-specific Dyt1 ∆GAG knock-in to basal ganglia and cerebellum reveal differential effects on motor behavior and sensorimotor network function. Exp Neurol 2023; 367:114471. [PMID: 37321386 PMCID: PMC10695146 DOI: 10.1016/j.expneurol.2023.114471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 06/08/2023] [Accepted: 06/12/2023] [Indexed: 06/17/2023]
Abstract
Dystonia is a neurological movement disorder characterized by repetitive, unintentional movements and disabling postures that result from sustained or intermittent muscle contractions. The basal ganglia and cerebellum have received substantial focus in studying DYT1 dystonia. It remains unclear how cell-specific ∆GAG mutation of torsinA within specific cells of the basal ganglia or cerebellum affects motor performance, somatosensory network connectivity, and microstructure. In order to achieve this goal, we generated two genetically modified mouse models: in model 1 we performed Dyt1 ∆GAG conditional knock-in (KI) in neurons that express dopamine-2 receptors (D2-KI), and in model 2 we performed Dyt1 ∆GAG conditional KI in Purkinje cells of the cerebellum (Pcp2-KI). In both of these models, we used functional magnetic resonance imaging (fMRI) to assess sensory-evoked brain activation and resting-state functional connectivity, and diffusion MRI to assess brain microstructure. We found that D2-KI mutant mice had motor deficits, abnormal sensory-evoked brain activation in the somatosensory cortex, as well as increased functional connectivity of the anterior medulla with cortex. In contrast, we found that Pcp2-KI mice had improved motor performance, reduced sensory-evoked brain activation in the striatum and midbrain, as well as reduced functional connectivity of the striatum with the anterior medulla. These findings suggest that (1) D2 cell-specific Dyt1 ∆GAG mediated torsinA dysfunction in the basal ganglia results in detrimental effects on the sensorimotor network and motor output, and (2) Purkinje cell-specific Dyt1 ∆GAG mediated torsinA dysfunction in the cerebellum results in compensatory changes in the sensorimotor network that protect against dystonia-like motor deficits.
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Affiliation(s)
- B J Wilkes
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
| | - R Z Adury
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - D Berryman
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - L R Concepcion
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Y Liu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - F Yokoi
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - C Maugee
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - Y Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA
| | - D E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Norman Fixel Institute for Neurological Diseases, Department of Neurology, University of Florida, Gainesville, FL, USA; Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
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Saberfard D, Sarchahi AA, Mehrjerdi HK. Effect of medetomidine, midazolam, ketamine, propofol and isoflurane on spinal reflexes in healthy dogs. Vet Med Sci 2022; 8:2351-2359. [DOI: 10.1002/vms3.938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Donya Saberfard
- Faculty of Veterinary Medicine Ferdowsi University of Mashhad Mashhad Iran
| | - Ali Asghar Sarchahi
- Faculty of Veterinary Medicine, Department of Clinical Sciences Ferdowsi University of Mashhad Mashhad Iran
| | - Hossein Kazemi Mehrjerdi
- Faculty of Veterinary Medicine, Department of Clinical Sciences Ferdowsi University of Mashhad Mashhad Iran
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Wilkes BJ, DeSimone JC, Liu Y, Chu WT, Coombes SA, Li Y, Vaillancourt DE. Cell-specific effects of Dyt1 knock-out on sensory processing, network-level connectivity, and motor deficits. Exp Neurol 2021; 343:113783. [PMID: 34119482 PMCID: PMC8324325 DOI: 10.1016/j.expneurol.2021.113783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/04/2021] [Accepted: 06/08/2021] [Indexed: 11/19/2022]
Abstract
DYT1 dystonia is a debilitating movement disorder characterized by repetitive, unintentional movements and postures. The disorder has been linked to mutation of the TOR1A/DYT1 gene encoding torsinA. Convergent evidence from studies in humans and animal models suggest that striatal medium spiny neurons and cholinergic neurons are important in DYT1 dystonia. What is not known is how torsinA dysfunction in these specific cell types contributes to the pathophysiology of DYT1 dystonia. In this study we sought to determine whether torsinA dysfunction in cholinergic neurons alone is sufficient to generate the sensorimotor dysfunction and brain changes associated with dystonia, or if torsinA dysfunction in a broader subset of cell types is needed. We generated two genetically modified mouse models, one with selective Dyt1 knock-out from dopamine-2 receptor expressing neurons (D2KO) and one where only cholinergic neurons are impacted (Ch2KO). We assessed motor deficits and performed in vivo 11.1 T functional MRI to assess sensory-evoked brain activation and connectivity, along with diffusion MRI to assess brain microstructure. We found that D2KO mice showed greater impairment than Ch2KO mice, including reduced sensory-evoked brain activity in key regions of the sensorimotor network, and altered functional connectivity of the striatum that correlated with motor deficits. These findings suggest that (1) the added impact of torsinA dysfunction in medium spiny and dopaminergic neurons of the basal ganglia generate more profound deficits than the dysfunction of cholinergic neurons alone, and (2) that sensory network impairments are linked to motor deficits in DYT1 dystonia.
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Affiliation(s)
- B J Wilkes
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
| | - J C DeSimone
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Y Liu
- Department of Neurology, University of Florida, Gainesville, FL, USA
| | - W T Chu
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - S A Coombes
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Y Li
- Department of Neurology, University of Florida, Gainesville, FL, USA
| | - D E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Neurology, University of Florida, Gainesville, FL, USA; Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
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Mauritz MD, Uhlenberg F, Vettorazzi E, Ebenebe CU, Singer D, Deindl P. Impact of Propofol Bolus Administration on the Nociceptive Flexion Reflex Threshold and Bispectral Index in Children—A Case Series. CHILDREN 2021; 8:children8080639. [PMID: 34438531 PMCID: PMC8393661 DOI: 10.3390/children8080639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 11/16/2022]
Abstract
We analyzed the impact of propofol administration during continuous sedation and analgesia on the nociceptive flexion reflex threshold (NFRT) and Bispectral Index (BIS) in ventilated children. We examined patients who received propofol before planned endotracheal suctioning. Patients were clinically assessed using the modified Face, Legs, Activity, Cry, Consolability (mFLACC) scale and COMFORT-B (Comfort Behavior) scale. We continuously recorded the NFRT and BIS. We recorded 23 propofol administrations in eight patients with an average age of 8.6 ± 3.5 years. The median (minimum-maximum) scores for the mFLACC scale and COMFORT-B scale were 0 (0–5) and 6 (6–17), respectively, before the bolus. The administration of a weight-adjusted propofol bolus of 1.03 ± 0.31 mg/kg resulted in an increase in NFRT and burst-suppression ratio; BIS and electromyogram values decreased. Changes from baseline (95% CI) after propofol bolus administration were BIS −23.9 (−30.8 to −17.1), EMG -10.5 dB (−13.3 to −7.7), SR 14.8 % (5.6 to 24.0) and NFRT 13.6 mA (5.5 to 21.7). Further studies are needed to determine whether sedated children may benefit from objective pain and sedation monitoring with BIS and NFRT.
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Affiliation(s)
- Maximilian David Mauritz
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children’s Hospital, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany; (F.U.); (C.U.E.); (D.S.); (P.D.)
- Department of General Pediatrics and Adolescent Medicine, Children’s and Adolescents’ Hospital Datteln, Witten/Herdecke University, 45711 Datteln, Germany
- Correspondence: ; Tel.: +49-2363-9750
| | - Felix Uhlenberg
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children’s Hospital, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany; (F.U.); (C.U.E.); (D.S.); (P.D.)
- Department of Pediatrics and Adolescent Medicine, Neonatology and Pediatric Intensive Care Medicine, Itzehoe Medical Center, 25524 Itzehoe, Germany
| | - Eik Vettorazzi
- Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany;
| | - Chinedu Ulrich Ebenebe
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children’s Hospital, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany; (F.U.); (C.U.E.); (D.S.); (P.D.)
| | - Dominique Singer
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children’s Hospital, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany; (F.U.); (C.U.E.); (D.S.); (P.D.)
| | - Philipp Deindl
- Department of Neonatology and Pediatric Intensive Care Medicine, University Children’s Hospital, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany; (F.U.); (C.U.E.); (D.S.); (P.D.)
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Mitochondrial Function and Anesthetic Sensitivity in the Mouse Spinal Cord. Anesthesiology 2021; 134:901-914. [PMID: 33909880 DOI: 10.1097/aln.0000000000003794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Ndufs4 knockout (KO) mice are defective in mitochondrial complex I function and hypersensitive to inhibition of spinal cord-mediated response to noxious stimuli by volatile anesthetics. It was hypothesized that, compared to wild-type, synaptic or intrinsic neuronal function is hypersensitive to isoflurane in spinal cord slices from knockout mice. METHODS Neurons from slices of the vestibular nucleus, central medial thalamus, and spinal cord from wild-type and the global Ndufs4 knockout were patch clamped. Unstimulated synaptic and intrinsic neuronal characteristics were measured in response to isoflurane. Norfluoxetine was used to block TREK channel conductance. Cholinergic cells were labeled with tdTomato. RESULTS All values are reported as means and 95% CIs. Spontaneous synaptic activities were not different between the mutant and control. Isoflurane (0.6%; 0.25 mM; Ndufs4[KO] EC95) increased the holding current in knockout (ΔHolding current, 126 pA [95% CI, 99 to 152 pA]; ΔHolding current P < 0.001; n = 21) but not wild-type (ΔHolding current, 2 7 pA [95% CI, 9 to 47 pA]; ΔHolding current, P = 0.030; n = 25) spinal cord slices. Knockout and wild-type ΔHolding currents were significantly different (P < 0.001). Changes comparable to those in the knockout were seen in the wild type only in 1.8% (0.74 mM) isoflurane (ΔHolding current, 72 pA [95% CI, 43 to 97 pA]; ΔHolding current, P < 0.001; n = 13), the control EC95. Blockade of action potentials indicated that the increased holding current in the knockout was not dependent on synaptic input (ΔHolding current, 154 pA [95% CI, 99 to 232 pA]; ΔHolding current, P = 0.506 compared to knockout without blockade; n = 6). Noncholinergic neurons mediated the increase in holding current sensitivity in Ndufs4 knockout. The increased currents were blocked by norfluoxetine. CONCLUSIONS Isoflurane increased an outwardly rectifying potassium current in ventral horn neurons of the Ndufs4(KO) mouse at a concentration much lower than in controls. Noncholinergic neurons in the spinal cord ventral horn mediated the effect. Presynaptic functions in Ndufs4(KO) slices were not hypersensitive to isoflurane. These data link anesthetic sensitivity, mitochondrial function, and postsynaptic channel activity. EDITOR’S PERSPECTIVE
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McPherson JG, Bandres MF. Spontaneous neural synchrony links intrinsic spinal sensory and motor networks during unconsciousness. eLife 2021; 10:e66308. [PMID: 34042587 PMCID: PMC8177891 DOI: 10.7554/elife.66308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 05/26/2021] [Indexed: 12/17/2022] Open
Abstract
Non-random functional connectivity during unconsciousness is a defining feature of supraspinal networks. However, its generalizability to intrinsic spinal networks remains incompletely understood. Previously, Barry et al., 2014 used fMRI to reveal bilateral resting state functional connectivity within sensory-dominant and, separately, motor-dominant regions of the spinal cord. Here, we record spike trains from large populations of spinal interneurons in vivo in rats and demonstrate that spontaneous functional connectivity also links sensory- and motor-dominant regions during unconsciousness. The spatiotemporal patterns of connectivity could not be explained by latent afferent activity or by populations of interconnected neurons spiking randomly. We also document connection latencies compatible with mono- and disynaptic interactions and putative excitatory and inhibitory connections. The observed activity is consistent with the hypothesis that salient, experience-dependent patterns of neural transmission introduced during behavior or by injury/disease are reactivated during unconsciousness. Such a spinal replay mechanism could shape circuit-level connectivity and ultimately behavior.
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Affiliation(s)
- Jacob Graves McPherson
- Program in Physical Therapy, Washington University School of MedicineSt. LouisUnited States
- Department of Anesthesiology, Washington University School of MedicineSt. LouisUnited States
- Washington University Pain Center, Washington University School of MedicineSt. LouisUnited States
- Program in Neurosciences, Washington University School of MedicineSt. LouisUnited States
| | - Maria F Bandres
- Program in Physical Therapy, Washington University School of MedicineSt. LouisUnited States
- Department of Biomedical Engineering, Washington University School of MedicineSt. LouisUnited States
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Zhao X, Zhou Z. Expression and Regulation of the GABA A Receptor/STEP61 Signaling Pathway in Cerebral Cortical Neurons Treated with Emulsified Isoflurane In Vitro. ACS Chem Neurosci 2020; 11:4329-4335. [PMID: 33232128 DOI: 10.1021/acschemneuro.0c00586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Emulsified isoflurane (EISO) is an intravenous anesthetic. However, researchers have not clearly determined how emulsified isoflurane affects the central nervous system during the process of anesthesia. The aim of this study was to explore changes in the gamma-aminobutyric acid type A receptor subunit (GABAA), 61 kD isoform of striatal-enriched protein phosphatase (STEP61) signaling pathway, and epigenetic regulation in cortical neurons after treatment with emulsified isoflurane. After immunological identification, the isolated neurons were randomly divided into three groups: the blank group (Con), intralipid treatment group (FE), and emulsified isoflurane treatment group (EISO). Neuron viability was assayed using cell counting kit-8 (CCK-8). The expression levels of target nucleic acids, proteins, and corresponding ligands were detected. Using real-time polymerase chain reaction (PCR) to assess the promoter methylation of ion channel proteins in the cerebral cortex of rats anesthetized with EISO, we observed changes in promoter methylation of the genes encoding gamma-aminobutyric acid type A receptor α1 subunit (GABAAα1), N-methyl-d-aspartate receptor subunit 1 (NMDAR1), and mu opioid receptor 1 (OPRM1), accompanied by changes in the levels of their messenger ribonucleic acids (mRNAs) and proteins. The levels of ligands for these receptors were also altered. EISO altered the methylation rate of the promoter region of channel protein-coding genes involved in the GABAA/STEP61 signaling pathway in cerebral cortical neurons to regulate gene expression. The ligands for the receptors were also changed.
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Affiliation(s)
- Xingkai Zhao
- Department of Veterinary Clinical Science, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, P. R. China
| | - Zhenlei Zhou
- Department of Veterinary Clinical Science, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, P. R. China
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Yang R, Zhao D, Zhang XH, Liu RH, Xu GH, Shen QY. Comparison of Sevoflurane and Propofol on the Incidence of Postoperative Pain and Quality of Life in Patients Undergoing Total Knee Arthroplasty With Chronic Pain Before Surgery. Pain Pract 2020; 21:37-44. [PMID: 32615020 DOI: 10.1111/papr.12931] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 06/21/2020] [Accepted: 06/25/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND Propofol and sevoflurane as frequently used general anesthetics can affect postoperative pain. Our study explored whether the incidence of postoperative pain differed among patients with chronic pain undergoing total knee arthroplasty (TKA) anesthetized with sevoflurane or propofol. METHODS Patients were randomly assigned to groups receiving either sevoflurane (Group S, n = 50) or propofol (Group P, n = 47) for anesthesia maintenance during TKA. The incidences of postoperative pain and quality of life (QoL) were measured using the EuroQol 5-Dimension (EQ-5D) scale at 1, 3, and 7 days post-operation (DPO), and 1 and 3 months post-operation (MPO). RESULTS At 3 DPO, fewer patients reported moderate pain (P = 0.001) and more patients reported no pain (P = 0.003) in Group S than that in Group P. At 3 MPO, more patients reported no pain (P = 0.04) and fewer patients reported moderate pain (P = 0.04) in Group S than in Group P. No significant differences were found in the incidence of postoperative pain between the 2 groups of patients at the other time points. The EQ-5D scores were higher in Group S than in Group P (P = 0.022), and the difference was 0.15 at most, which was not optimal. The EQ-5D clinical results might be not very significant. CONCLUSIONS Sevoflurane anesthesia may have potential advantages in reducing postoperative pain in patients undergoing TKA with a preoperative VAS score > 4.
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Affiliation(s)
- Rui Yang
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China
| | - Dan Zhao
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China
| | - Xiao-Hui Zhang
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China
| | - Rui-Hong Liu
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China
| | - Guang-Hong Xu
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China.,Department of Neurology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China
| | - Qi-Ying Shen
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China
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Proportional Downscaling of Glutamatergic Release Sites by the General Anesthetic Propofol at Drosophila Motor Nerve Terminals. eNeuro 2020; 7:ENEURO.0422-19.2020. [PMID: 32019872 PMCID: PMC7053172 DOI: 10.1523/eneuro.0422-19.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 01/21/2020] [Accepted: 01/24/2020] [Indexed: 01/12/2023] Open
Abstract
Propofol is the most common general anesthetic used for surgery in humans, yet its complete mechanism of action remains elusive. In addition to potentiating inhibitory synapses in the brain, propofol also impairs excitatory neurotransmission. We use electrophysiological recordings from individual glutamatergic boutons in male and female larval Drosophila melanogaster motor nerve terminals to characterize this effect. We recorded from two bouton types, which have distinct presynaptic physiology and different average numbers of release sites or active zones. We show that a clinically relevant dose of propofol (3 μm) impairs neurotransmitter release similarly at both bouton types by decreasing the number of active release sites by half, without affecting release probability. In contrast, an analog of propofol has no effect on glutamate release. Coexpressing a truncated syntaxin1A protein in presynaptic boutons completely blocked this effect of propofol. Overexpressing wild-type syntaxin1A in boutons also conferred a level of resistance by increasing the number of active release sites to a physiological ceiling set by the number of active zones or T-bars, and in this way counteracting the effect of propofol. These results point to the presynaptic release machinery as a target for the general anesthetic. Proportionally equivalent effects of propofol on the number of active release sites across the different bouton types suggests that glutamatergic circuits that involve smaller boutons with fewer release sites may be more vulnerable to the presynaptic effects of the drug.
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Lin WL, Lee MS, Wong CS, Chan SM, Lai HC, Wu ZF, Lu CH. Effects of intraoperative propofol-based total intravenous anesthesia on postoperative pain in spine surgery: Comparison with desflurane anesthesia - a randomised trial. Medicine (Baltimore) 2019; 98:e15074. [PMID: 30921241 PMCID: PMC6456101 DOI: 10.1097/md.0000000000015074] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND As reported, patients experience less postoperative pain after propofol-based total intravenous anesthesia (TIVA). In the present study, we investigated the postoperative analgesic effects between propofol-based TIVA and desflurane anesthesia after spine surgery. METHODS Sixty patients were included who received (surgical time >180 minutes) lumbar spine surgery. Patients were randomly assigned to receive either TIVA (with target-controlled infusion) with propofol/fentanyl-based anesthesia (TIVA group) or desflurane/fentanyl-based anesthesia (DES group), titrated to maintain Bispectral Index values between 45 and 55. All patients received patient-controlled analgesia (PCA) with fentanyl for postoperative pain relief. Numeric pain rating scale (NRS) pain scores, postoperative fentanyl consumption, postoperative rescue tramadol use, and fentanyl-related side effects were recorded. RESULTS The TIVA group patients reported lower NRS pain scores during coughing on postoperative day 1 but not day 2 and 3 (P = .002, P = .133, P = .161, respectively). Less fentanyl consumption was observed on postoperative days 1 and 2, but not on day 3 (375 μg vs 485 μg, P = .032, 414 μg vs 572 μg, P = .033, and 421 μg vs 479 μg, P = .209, respectively), less cumulative fentanyl consumption at postoperative 48 hours (790 μg vs 1057 μg, P = .004) and 72 hours (1210 μg vs 1536 μg, P = .004), and total fentanyl consumption (1393 μg vs 1704 μg, P = .007) when compared with the DES group. No difference was found in rescue tramadol use and fentanyl-related side effects. CONCLUSION Patients anesthetized with propofol-based TIVA reported less pain during coughing and consumed less daily and total PCA fentanyl after lumbar spine surgery.
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Affiliation(s)
- Wei-Lin Lin
- Department of Anesthesiology, Tri-Service General Hospital and National Defense Medical Center
| | | | - Chih-Shung Wong
- Department of Anesthesiology, Cathay General Hospital, Taipei
| | - Shun-Ming Chan
- Department of Anesthesiology, Tri-Service General Hospital and National Defense Medical Center
| | - Hou-Chuan Lai
- Department of Anesthesiology, Tri-Service General Hospital and National Defense Medical Center
| | - Zhi-Fu Wu
- Department of Anesthesiology, Tri-Service General Hospital and National Defense Medical Center
- Department of Anesthesiology, Chi Mei Medical Center, Tainan, Taiwan, Republic of China
| | - Chueng-He Lu
- Department of Anesthesiology, Tri-Service General Hospital and National Defense Medical Center
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Toossi A, Everaert DG, Uwiera RRE, Hu DS, Robinson K, Gragasin FS, Mushahwar VK. Effect of anesthesia on motor responses evoked by spinal neural prostheses during intraoperative procedures. J Neural Eng 2019; 16:036003. [PMID: 30790787 DOI: 10.1088/1741-2552/ab0938] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE The overall goal of this study was to investigate the effects of various anesthetic protocols on the intraoperative responses to intraspinal microstimulation (ISMS). ISMS is a neuroprosthetic approach that targets the motor networks in the ventral horns of the spinal cord to restore function after spinal cord injury. In preclinical studies, ISMS in the lumbosacral enlargement produced standing and walking by activating networks controlling the hindlimb muscles. ISMS implants are placed surgically under anesthesia, and refinements in placement are made based on the evoked responses. Anesthesia can have a significant effect on the responses evoked by spinal neuroprostheses; therefore, in preparation for clinical testing of ISMS, we compared the evoked responses under a common clinical neurosurgical anesthetic protocol with those evoked under protocols commonly used in preclinical studies. APPROACH Experiments were conducted in seven pigs. An ISMS microelectrode array was implanted in the lumbar enlargement and responses to ISMS were measured under three anesthetic protocols: (1) isoflurane, an agent used pre-clinically and clinically, (2) total intravenous anesthesia (TIVA) with propofol as the main agent commonly used in clinical neurosurgical procedures, (3) TIVA with sodium pentobarbital, an anesthetic agent used mostly preclinically. Responses to ISMS were evaluated based on stimulation thresholds, movement kinematics, and joint torques. Motor evoked potentials (MEP) and plasma concentrations of propofol were also measured. MAIN RESULTS ISMS under propofol anesthesia produced large and functional responses that were not statistically different from those produced under pentobarbital anesthesia. Isoflurane, however, significantly suppressed the ISMS-evoked responses. SIGNIFICANCE This study demonstrated that the choice of anesthesia is critical for intraoperative assessments of motor responses evoked by spinal neuroprostheses. Propofol and pentobarbital anesthesia did not overly suppress the effects of ISMS; therefore, propofol is expected to be a suitable anesthetic agent for clinical intraoperative testing of an intraspinal neuroprosthetic system.
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Affiliation(s)
- Amirali Toossi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada. Sensory Motor Adaptive Rehabilitative Technology (SMART) Network, University of Alberta, Edmonton, AB, Canada
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McGaraughty S, Chu KL, Xu J. Characterization and pharmacological modulation of noci-responsive deep dorsal horn neurons across diverse rat models of pathological pain. J Neurophysiol 2018; 120:1893-1905. [DOI: 10.1152/jn.00325.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This overview compares the activity of wide dynamic range (WDR) and nociceptive specific (NS) neurons located in the deep dorsal horn across different rat models of pathological pain and following modulation by diverse pharmacology. The data were collected by our group under the same experimental conditions over numerous studies to facilitate comparison. Spontaneous firing of WDR neurons was significantly elevated (>3.7 Hz) in models of neuropathic, inflammation, and osteoarthritic pain compared with naive animals (1.9 Hz) but was very low (<0.5 Hz) and remained unchanged in NS neurons. WDR responses to low-intensity mechanical stimulation were elevated in neuropathic and inflammation models. WDR responses to high-intensity stimuli were enhanced in inflammatory (heat) and osteoarthritis (mechanical) models. NS responses to high-intensity stimulation did not change relative to control in any model examined. Several therapeutic agents reduced both evoked and spontaneous firing of WDR neurons (e.g., TRPV1, TRPV3, Nav1.7, Nav1.8, P2X7, P2X3, H3), other targets affected neither evoked nor spontaneous firing of WDR neurons (e.g., H4, TRPM8, KCNQ2/3), and some only modulated evoked (e.g, ASIC1a, Cav3.2) whereas others decreased evoked but affected spontaneous activity only in specific models (e.g., TRPA1, CB2). Spontaneous firing of WDR neurons was not altered by any peripherally restricted compound or by direct administration of compounds to peripheral sites, although the same compounds decreased evoked activity. Compounds acting centrally were effective against this endpoint. The diversity of incoming/modulating inputs to the deep dorsal horn positions this group of neurons as an important intersection within the pain system to validate novel therapeutics. NEW & NOTEWORTHY Data from multiple individual experiments were combined to show firing properties of wide dynamic range and nociceptive specific spinal dorsal horn neurons across varied pathological pain models. This high-powered analysis describes the sensitization following different forms of injury. Effects of diverse pharmacology on these neurons is also summarized from published and unpublished data all recorded under the same conditions to facilitate comparison. This comprehensive overview describes the function and utility of these neurons.
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Affiliation(s)
| | | | - Jun Xu
- AbbVie Discovery, North Chicago, Illinois
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Lervik A, Raszplewicz J, Ranheim B, Solbak S, Toverud SF, Haga HA. Dexmedetomidine or fentanyl? Cardiovascular stability and analgesia during propofol-ketamine total intravenous anaesthesia in experimental pigs. Vet Anaesth Analg 2018; 45:295-308. [DOI: 10.1016/j.vaa.2017.08.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/13/2017] [Accepted: 08/29/2017] [Indexed: 10/18/2022]
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Reed R, Doherty T. Minimum alveolar concentration: Key concepts and a review of its pharmacological reduction in dogs. Part 1. Res Vet Sci 2018; 117:266-270. [PMID: 29331922 DOI: 10.1016/j.rvsc.2018.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 11/25/2017] [Accepted: 01/08/2018] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To outline the major components of the minimum alveolar concentration (MAC) and review the literature in regard to pharmacological manipulation of the MAC of halothane, isoflurane, sevoflurane, enflurane, and desflurane in dogs. The pharmacologic agents included are alpha-2 agonists, benzodiazepines, propofol, maropitant, opioids, lidocaine, acepromazine, non-steroidal anti-inflammatory agents, and NMDA antagonists. Part 1 will focus on summarizing the relevance, measurement, and mechanisms of MAC and review the effects of alpha-2 agonists, benzodiazepines, and propofol on MAC. DATABASES USED PubMed, Google Scholar, CAB Abstracts. Search terms used: minimum alveolar concentration, MAC, dog, canine, inhaled anesthetic potency, isoflurane, sevoflurane, desflurane, enflurane, and halothane. CONCLUSIONS Many drugs reduce the MAC of inhaled anesthetics in dogs, and allow for a clinically important decrease in inhalant anesthetic use. A decrease in MAC may decrease the adverse cardiovascular and pulmonary effects associated with the use of high concentrations of inhaled anesthetics.
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Affiliation(s)
- Rachel Reed
- University of Georgia College of Veterinary Medicine, 2200 College Station Rd., Athens, GA 30605, USA.
| | - Thomas Doherty
- University of Tennessee College of Veterinary Medicine, 2407 River Dr., Knoxville, TN 37996, USA.
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Jakuscheit A, Posch MJ, Gkaitatzis S, Neumark L, Hackbarth M, Schneider M, Lichtner G, Baars JH, von Dincklage F. Utility of nociceptive flexion reflex threshold and bispectral index to predict movement responses under propofol anaesthesia. Somatosens Mot Res 2017; 34:139-144. [DOI: 10.1080/08990220.2017.1343189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Axel Jakuscheit
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Matthias J. Posch
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Stefanos Gkaitatzis
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Lisa Neumark
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Mark Hackbarth
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Martin Schneider
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Gregor Lichtner
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Jan H. Baars
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Falk von Dincklage
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité – Universitätsmedizin Berlin, Berlin, Germany
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Hunt J, Murrell J, Knazovicky D, Harris J, Kelly S, Knowles TG, Lascelles BDX. Alfaxalone Anaesthesia Facilitates Electrophysiological Recordings of Nociceptive Withdrawal Reflexes in Dogs (Canis familiaris). PLoS One 2016; 11:e0158990. [PMID: 27433936 PMCID: PMC4951135 DOI: 10.1371/journal.pone.0158990] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 06/25/2016] [Indexed: 12/02/2022] Open
Abstract
Naturally occurring canine osteoarthritis represents a welfare issue for affected dogs (Canis familiaris), but is also considered very similar to human osteoarthritis and has therefore been proposed as a model of disease in humans. Central sensitisation is recognized in human osteoarthritis sufferers but identification in dogs is challenging. Electromyographic measurement of responses to nociceptive stimulation represents a potential means of investigating alterations in central nociceptive processing, and has been evaluated in conscious experimental dogs, but is likely to be aversive. Development of a suitable anaesthetic protocol in experimental dogs, which facilitated electrophysiological nociceptive withdrawal reflex assessment, may increase the acceptability of using the technique in owned dogs with naturally occurring osteoarthritis. Seven purpose bred male hound dogs underwent electromyographic recording sessions in each of three states: acepromazine sedation, alfaxalone sedation, and alfaxalone anaesthesia. Electromyographic responses to escalating mechanical and electrical, and repeated electrical, stimuli were recorded. Subsequently the integral of both early and late rectified responses was calculated. Natural logarithms of the integral values were analysed within and between the three states using multi level modeling. Alfaxalone increased nociceptive thresholds and decreased the magnitude of recorded responses, but characteristics of increasing responses with increasing stimulus magnitude were preserved. Behavioural signs of anxiety were noted in two out of seven dogs during recordings in the acepromazine sedated state. There were few significant differences in response magnitude or nociceptive threshold between the two alfaxalone states. Following acepromazine premedication, induction of anaesthesia with 1–2 mg kg-1 alfaxalone, followed by a continuous rate infusion in the range 0.075–0.1 mg kg-1 min-1 produced suitable conditions to enable assessment of spinal nociceptive processing in dogs, without subjecting them to potentially aversive experiences. This methodology may be appropriate for obtaining electrophysiological nociceptive withdrawal reflex data in client-owned dogs with naturally occurring osteoarthritis.
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Affiliation(s)
- James Hunt
- School of Veterinary Sciences, University of Bristol, Bristol, United Kingdom
| | - Jo Murrell
- School of Veterinary Sciences, University of Bristol, Bristol, United Kingdom
| | - David Knazovicky
- Comparative Pain Research Laboratory, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America
| | - John Harris
- Division of Animal Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Sara Kelly
- Division of Animal Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Toby G. Knowles
- School of Veterinary Sciences, University of Bristol, Bristol, United Kingdom
| | - B. Duncan X. Lascelles
- Comparative Pain Research Laboratory, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America
- Center for Pain Research and Innovation, UNC School of Dentistry, Chapel Hill, North Carolina, United States of America
- Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
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Recio-Pinto E, Montoya-Gacharna JV, Xu F, Blanck TJJ. Isoflurane, but Not the Nonimmobilizers F6 and F8, Inhibits Rat Spinal Cord Motor Neuron CaV1 Calcium Currents. Anesth Analg 2016; 122:730-737. [PMID: 26702867 DOI: 10.1213/ane.0000000000001111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Volatile anesthetics decrease Ca²⁺ entry through voltage-dependent Ca²⁺ channels. Ca influences neurotransmitter release and neuronal excitability. Because volatile anesthetics act specifically on the spinal cord to produce immobility, we examined the effect of isoflurane and the nonimmobilizers F6 (1, 2-dichlorohexafluorocyclobutane) and F8 (2, 3-dichlorooctafluorobutane) on CaV1 and CaV2 Ca²⁺ channels in spinal cord motor neurons and dorsal root ganglion neurons. METHODS Using patch clamping, we compared the effects of isoflurane with those of F6 and F8 on CaV1 and CaV2 channels in isolated, cultured adult rat spinal cord motor neurons and on CaV1 and CaV2 channels in adult rat dorsal root ganglion sensory neurons. RESULTS In spinal cord motor neurons, isoflurane, but not F6 or F8, inhibited currents through CaV1 channels. Isoflurane and at least one of the nonimmobilizers inhibited currents through CaV1 and CaV2 channels in dorsal root ganglion neurons and CaV2 in spinal cord motor neurons. CONCLUSIONS The findings that isoflurane, but not nonimmobilizers, inhibited CaV1 Ca²⁺ channels in spinal cord motor neurons are consistent with the notion that spinal cord motor neurons might mediate isoflurane-induced immobility. Additional studies are required to examine whether inhibition of CaV1 calcium currents in spinal cord motor neurons is sufficient or whether actions on other channels/proteins contribute to isoflurane-induced immobility.
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Affiliation(s)
- Esperanza Recio-Pinto
- From the Department of Anesthesiology, NYU Langone Medical Center, New York, New York
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Petrosyan HA, Alessi V, Hunanyan AS, Sisto SA, Arvanian VL. Spinal electro-magnetic stimulation combined with transgene delivery of neurotrophin NT-3 and exercise: novel combination therapy for spinal contusion injury. J Neurophysiol 2015; 114:2923-40. [PMID: 26424579 DOI: 10.1152/jn.00480.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 09/29/2015] [Indexed: 12/12/2022] Open
Abstract
Our recent terminal experiments revealed that administration of a single train of repetitive spinal electromagnetic stimulation (sEMS; 35 min) enhanced synaptic plasticity in spinal circuitry following lateral hemisection spinal cord injury. In the current study, we have examined effects of repetitive sEMS applied as a single train and chronically (5 wk, every other day) following thoracic T10 contusion. Chronic studies involved examination of systematic sEMS administration alone and combined with exercise training and transgene delivery of neurotrophin [adeno-associated virus 10-neurotrophin 3 (AAV10-NT3)]. Electrophysiological intracellular/extracellular recordings, immunohistochemistry, behavioral testing, and anatomical tracing were performed to assess effects of treatments. We found that administration of a single sEMS train induced transient facilitation of transmission through preserved lateral white matter to motoneurons and hindlimb muscles in chronically contused rats with effects lasting for at least 2 h. These physiological changes associated with increased immunoreactivity of GluR1 and GluR2/3 glutamate receptors in lumbar neurons. Systematic administration of sEMS alone for 5 wk, however, was unable to induce cumulative improvements of transmission in spinomuscular circuitry or improve impaired motor function following thoracic contusion. Encouragingly, chronic administration of sEMS, followed by exercise training (running in an exercise ball and swimming), induced the following: 1) sustained strengthening of transmission to lumbar motoneurons and hindlimb muscles, 2) better retrograde transport of anatomical tracer, and 3) improved locomotor function. Greatest improvements were seen in the group that received exercise combined with sEMS and AAV-NT3.
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Affiliation(s)
- Hayk A Petrosyan
- Northport Veterans Affairs Medical Center, Northport, New York; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York; and
| | - Valentina Alessi
- Northport Veterans Affairs Medical Center, Northport, New York; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York; and
| | | | - Sue A Sisto
- Department of Physical Therapy, Division of Rehabilitation Sciences, Stony Brook University, Stony Brook, New York
| | - Victor L Arvanian
- Northport Veterans Affairs Medical Center, Northport, New York; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York; and
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Eckle VS, Grasshoff C, Mirakaj V, O'Neill PM, Berry NG, Leuwer M, Antkowiak B. 4-bromopropofol decreases action potential generation in spinal neurons by inducing a glycine receptor-mediated tonic conductance. Br J Pharmacol 2015; 171:5790-801. [PMID: 25131750 DOI: 10.1111/bph.12880] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 07/29/2014] [Accepted: 08/11/2014] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Impaired function of spinal strychnine-sensitive glycine receptors gives rise to chronic pain states and movement disorders. Therefore, increased activity of glycine receptors should help to treat such disorders. Although compounds targeting glycine receptors with a high selectivity are lacking, halogenated analogues of propofol have recently been considered as potential candidates. Therefore we asked whether 4-bromopropofol attenuated the excitability of spinal neurons by promoting glycine receptor-dependent inhibition. EXPERIMENTAL APPROACH The actions of sub-anaesthetic concentrations of propofol and 4-bromopropofol were investigated in spinal tissue cultures prepared from mice. Drug-induced alterations in action potential firing were monitored by extracellular multi-unit recordings. The effects on GABAA and glycine receptor-mediated inhibition were quantified by whole-cell voltage-clamp recordings. KEY RESULTS Low concentrations of 4-bromopropofol (50 nM) reduced action potential activity of ventral horn neurons by about 30%, compared with sham-treated slices. This effect was completely abolished by strychnine (1 μM). In voltage-clamped neurons, 4-bromopropofol activated glycine receptors, generating a tonic current of 65 ± 10 pA, while GABAA - and glycine receptor-mediated synaptic transmission remained unaffected. CONCLUSIONS AND IMPLICATIONS The highest glycine levels in the CNS are found in the ventral horn of the spinal cord, a region mediating pain-induced motor reflexes and participating in the control of muscle tone. 4-Bromopropofol may serve as a starting point for the development of non-sedative, non-addictive, muscle relaxants and analgesics to be used to treat low back pain.
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Affiliation(s)
- V S Eckle
- Experimental Anaesthesiology Section, Department of Anaesthesiology and Intensive Care, Eberhard-Karls-University, Tübingen, Germany
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Singsank-Coats J, Seddighi R, Rohrbach BW, Cox SK, Egger CM, Doherty TJ. The anesthetic interaction of propofol and sevoflurane on the minimum alveolar concentration preventing motor movement (MACNM) in dogs. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2015; 79:95-100. [PMID: 25852224 PMCID: PMC4365712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 07/11/2014] [Indexed: 06/04/2023]
Abstract
The objective of this study was to determine the effects of propofol on the minimum alveolar concentration of sevoflurane needed to prevent motor movement (MAC(NM)) in dogs subjected to a noxious stimulus using randomized crossover design. Six, healthy, adult beagles (9.2 ± 1.3 kg) were used. Dogs were anesthetized with sevoflurane on 3 occasions, at weekly intervals, and baseline MAC(NM) (MAC(NM-B)) was determined on each occasion. Propofol treatments were administered as loading dose (LD) and constant rate infusion (CRI) as follows: Treatment 1 (T1) was 2 mg/kg body weight (BW) and 4.5 mg/kg BW per hour; T2 was 4 mg/kg BW and 9 mg/kg BW per hour; T3 was 8 mg/kg BW and 18 mg/kg BW per hour, respectively. Treatment MAC(NM) (MAC(NM-T)) determination was initiated 60 min after the start of the CRI. Two venous blood samples were collected and combined at each MAC(NM-T) determination for measurement of blood propofol concentration using high-performance liquid chromatography method (HPLC). Data were analyzed using a mixed-model ANOVA and are presented as least square means (LSM) ± standard error of means (SEM). Propofol infusions in the range of 4.5 to 18 mg/kg BW per hour resulted in mean blood concentrations between 1.3 and 4.4 μg/mL, and decreased (P < 0.05) sevoflurane MAC(NM) in a concentration-dependent manner. The percentage decrease in MAC(NM) was 20.5%, 43.0%, and 68.3%, with corresponding blood propofol concentrations of 1.3 ± 0.3 μg/mL, 2.5 ± 0.3 μg/mL, and 4.4 ± 0.3 μg/mL, for T1, T2, and T3, respectively. Venous blood propofol concentrations were strongly correlated (r = 0.855, P < 0.0001) with the decrease in MAC(NM). In dogs, propofol decreased the sevoflurane MAC(NM) in a concentration-dependent manner.
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Affiliation(s)
| | - Reza Seddighi
- Address all correspondence to Dr. Reza Seddighi; telephone: (865) 974-8387; fax: (865) 974-5773; e-mail:
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Truchetti G, Burns P, Nichols S, Parent J. Effects of isoflurane on somatosensory-evoked potentials in calves: a pilot study. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2015; 79:22-30. [PMID: 25673905 PMCID: PMC4283230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 04/20/2014] [Indexed: 06/04/2023]
Abstract
Somatosensory evoked potentials (SSEP) are used to monitor sensory function and are often recorded under general anesthesia. The objective of the study was to evaluate the effects of isoflurane on SSEPs in calves as it has not been reported. Eight calves (mean age: 40 days), were included in the study. Calves were anesthetized with a randomized sequence of four different isoflurane partial pressures. Blood gas analysis was performed before each measurement. SSEP were induced by repeated stimulation of the common dorsal digital nerve III. SSEPs were recorded from the lumbo-sacral junction (s-SSEP) and the head (c-SSEP). Latency and inter-amplitude of each peak were measured. For s-SSEP: One negative (Nsp1) and two positive (Psp1 and Psp2) peaks were identified in all tracings except for two calves. There was a significant effect of isoflurane on the latency of Psp2 (P = 0.01). Inter-amplitude decreased significantly with PaO2, PaCO2 and temperature (P < 0.05). Psp2 latency decreased with PaO2 (P = 0.01). For c-SSEP: two positive (Pc1 and Pc2) and two negative (Nc1 and Nc2) peaks were identified. There were identifiable peaks for the analysis of Pc1 latencies only. There was a significant positive linear relation between end-tidal isoflurane partial pressure (ETiso) and Pc1 latency (P = 0.04). None of the co-variables had a significant effect on the latency of Pc1 (P > 0.1). Isoflurane has a major impact on the recording of c-SSEP. Recording should be done at the lowest ETiso as possible, and anesthesia parameters should be kept constant.
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Affiliation(s)
| | - Patrick Burns
- Address all correspondence to Dr. Patrick Burns; telephone: (450) 773-8521, ext. 8253; fax: (450) 778-8158; e-mail:
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Lavertu G, Côté SL, De Koninck Y. Enhancing K–Cl co-transport restores normal spinothalamic sensory coding in a neuropathic pain model. Brain 2013; 137:724-38. [DOI: 10.1093/brain/awt334] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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ALX 1393 inhibits spontaneous network activity by inducing glycinergic tonic currents in the spinal ventral horn. Neuroscience 2013; 253:165-71. [DOI: 10.1016/j.neuroscience.2013.08.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 08/19/2013] [Accepted: 08/22/2013] [Indexed: 11/22/2022]
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Liang L, Mendell LM. Bilateral transient changes in thalamic nucleus ventroposterior lateralis after thoracic hemisection in the rat. J Neurophysiol 2013; 110:942-51. [PMID: 23741041 DOI: 10.1152/jn.00998.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We made simultaneous bilateral recordings of unit activity in the nucleus ventroposterior lateralis (VPL) in intact rats and after acute and chronic left thoracic hemisection. We observed an immediate bilateral decline in multireceptive units, reflecting a loss of nociceptive input on the lesion side and a loss of low-threshold inputs contralaterally. Unit properties were restored to normal by 6 wk. Mean spontaneous discharge frequency remained unchanged in left VPL at all intervals. Right VPL displayed a substantial increase in spontaneous discharge frequency at 2 and 4 wk, returning to normal by 6 wk. Activity in left VPL driven by Pinch or Brush of the right limb was unchanged except for an immediate decrease in the response to Pinch, which was reversed by 2 wk despite persistent left hemisection. In right VPL, the response to Pinch or Brush of the left hindlimb was enhanced at 2 and 4 wk but returned to normal by 6 wk. Behaviorally, the same rats displayed increased sensitivity to mechanical stimulation of the left hindlimb, but, unlike VPL activity, there was no significant behavioral recovery. Bursting cells were also observed bilaterally in VPL, but this did not match the restriction of scratches to the hindlimb contralateral to the hemisection considered to be evidence for neuropathic pain. The novel findings include recovery of responsiveness to Pinch on the side ipsilateral to the hemisection despite the lack of spinothalamic input as well as failure for the thalamus contralateral to hemisection to maintain its elevated responsiveness.
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Affiliation(s)
- Li Liang
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794-5230, USA
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Voulgaris DA, Egger CM, Seddighi MR, Rohrbach BW, Love LC, Doherty TJ. The effect of nitrous oxide on the minimum alveolar concentration (MAC) and MAC derivatives of isoflurane in dogs. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2013; 77:131-135. [PMID: 24082405 PMCID: PMC3605929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 02/15/2012] [Indexed: 06/02/2023]
Abstract
This study investigated the effects of 70% nitrous oxide (N2O) on the minimum alveolar concentration (MAC) of isoflurane (ISO) that prevents purposeful movement, the MAC of ISO at which there is no motor movement (MACNM), and the MAC of ISO at which autonomic responses are blocked (MACBAR) in dogs. Six adult, healthy, mixed-breed, intact male dogs were anesthetized with ISO delivered via mask. Baseline MAC, MACNM, and MACBAR of ISO were determined for each dog using a supra-maximal electrical stimulus (50 V, 50 Hz, 10 ms). Nitrous oxide (70%) was then administered and MAC and its derivatives (N2O-MAC, N2O-MACNM, and N2O-MACBAR) were determined using the same methodology. The values for baseline MAC, MACNM, and MACBAR were 1.39 ± 0.14, 1.59 ± 0.10, and 1.72 ± 0.16, respectively. The addition of 70% N2O decreased MAC, MACNM, and MACBAR by 32%, 15%, and 25%, respectively.
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Affiliation(s)
| | - Christine M. Egger
- Address all correspondence to Dr. Christine M. Egger; telephone: (865) 974-8387; fax: (865) 974-5554; e-mail:
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Takechi K, Carstens MI, Klein AH, Carstens E. The antinociceptive and antihyperalgesic effects of topical propofol on dorsal horn neurons in the rat. Anesth Analg 2013; 116:932-8. [PMID: 23337417 DOI: 10.1213/ane.0b013e31827f560d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Propofol (2,6-diisopropylphenol) is an IV anesthetic used for general anesthesia. Recent evidence suggests that propofol-anesthetized patients experience less postoperative pain, and that propofol has analgesic properties when applied topically. We presently investigated the antinociceptive effects of topical propofol using behavioral and single-unit electrophysiological methods in rats. METHODS In behavioral experiments with rats, we assessed the effect of topical hindpaw application of propofol (1%-25%) on heat and mechanically evoked paw withdrawals. In electrophysiological experiments, we recorded from lumbar dorsal horn wide dynamic range (WDR)-type neurons in pentobarbital-anesthetized rats. We assessed the effect of topical application of propofol to the ipsilateral hindpaw on neuronal responses elicited by noxious heat, cold, and mechanical stimuli. We additionally tested whether propofol blocks heat sensitization of paw withdrawals and WDR neuronal responses induced by topical application of allyl isothiocyanate (AITC; mustard oil). RESULTS Topical application of propofol (1%-25%) significantly increased the mean latency of the thermally evoked hindpaw withdrawal reflex on the treated (but not opposite) side in a concentration-dependent manner, with no effect on mechanically evoked hindpaw withdrawal thresholds. Propofol also prevented shortening of paw withdrawal latency induced by AITC. In electrophysiological experiments, topical application of 10% and 25% propofol, but not 1% propofol or vehicle (10% intralipid), to the ipsilateral hindpaw significantly attenuated the magnitude of responses of WDR neurons to noxious heating of glabrous hindpaw skin with no significant change in thermal thresholds. Maximal suppression of noxious heat-evoked responses was achieved 15 minutes after application followed by recovery to the pre-propofol baseline by 30 minutes. Responses to skin cooling or graded mechanical stimuli were not significantly affected by any concentration of propofol. Topical application of AITC enhanced the noxious heat-evoked response of dorsal horn neurons. This enhancement of heat-evoked responses was attenuated when 10% propofol was applied topically after application of AITC. CONCLUSIONS The results indicate that topical propofol inhibits responses of WDR neurons to noxious heat consistent with analgesia, and reduced AITC sensitization of WDR neurons consistent with an antihyperalgesic effect. These results are consistent with clinical studies demonstrating reduced postoperative pain in surgical patients anesthetized with propofol. The mechanism of analgesic action of topical propofol is not clear, but may involve desensitization of TRPV1 or TRPA1 receptors expressed in peripheral nociceptive nerve endings, engagement of endocannabinoids, or activation of peripheral γ-aminobutyric acid A receptors.
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Affiliation(s)
- Kenichi Takechi
- Department of Anesthesiology and Resuscitology, Ehime University Medical School, Matsuyama, Japan
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Abstract
Inhaled agents represent an important and useful class of drugs for equine anesthesia. This article reviews the ether-type anesthetics in contemporary use, their uptake and elimination, their mechanisms of action, and their desirable and undesirable effects in horses.
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Affiliation(s)
- Robert J Brosnan
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
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Lervik A, Haga HA, Ranheim B, Spadavecchia C. The influence of a continuous rate infusion of dexmedetomidine on the nociceptive withdrawal reflex and temporal summation during isoflurane anaesthesia in dogs. Vet Anaesth Analg 2012; 39:414-25. [PMID: 22413770 DOI: 10.1111/j.1467-2995.2012.00713.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To examine the influence of a low dose dexmedetomidine infusion on the nociceptive withdrawal reflex and temporal summation in dogs during isoflurane anaesthesia. STUDY DESIGN Prospective experimental blinded cross-over study. ANIMALS Eight healthy mixed breed dogs, body weight Mean ± SD 26.5 ± 8.4 kg and age 25 ± 16 months. METHODS Anaesthesia was induced with propofol and maintained with isoflurane (Fe'ISO 1.3%) delivered in oxygen and air. After stabilization, baseline recordings (time 0) were obtained, then a dexmedetomidine bolus (1 μg kg(-1) IV) followed by a continuous rate infusion (1 μg kg(-1) hour(-1)) or saline placebo were administered. At times 10, 30 and 60 minutes after the initial bolus, electrical stimulations of increasing intensity were applied over the lateral plantar digital nerve, and administered both as single and as repeated stimuli. The resulting reflex responses were recorded using electromyography. Data were analysed using a multivariable linear regression model and a Kruskal Wallis test for single stimulation data, and repeated measures anova and paired t-test for repeated stimulation data. RESULTS The AUC for the stimulus-response curves after single stimulation were similar for both treatments at time 0. At times 10, 30 and 60 the AUCs for the stimulus-response curves were significantly lower with dexmedetomidine treatment than with placebo. Temporal summation was evident in both treatments at times 0, 10, 30 and 60 starting from a stimulation intensity of 10 mA. The magnitude of temporal summation was smaller in dexmedetomidine than in placebo treated dogs at time 10, 30 and 60, but not at time 0. CONCLUSIONS During isoflurane anaesthesia, low dose dexmedetomidine suppresses the nociceptive reflex responses after single and repeated electrical stimulation. CLINICAL RELEVANCE This experimental study confirms previous reports on its peri-operative efficacy under clinical conditions, and further indicates that dexmedetomidine might reduce the risk of post-operative chronic pain development.
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Affiliation(s)
- Andreas Lervik
- Department of Companion Animal Clinical Sciences, Norwegian School of Veterinary Science, Oslo, Norway.
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Jinks SL, Andrada J. Validation and Insights of Anesthetic Action in an Early Vertebrate Network. Anesth Analg 2011; 113:1033-42. [DOI: 10.1213/ane.0b013e3182273c34] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Anesthetic effects on fictive locomotion in the rat isolated spinal cord. Neuroreport 2011; 22:655-9. [PMID: 21817927 DOI: 10.1097/wnr.0b013e32834a20f2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
General anesthetic mechanisms are poorly understood. Anesthetic immobilizing effects occur in the spinal ventral horn. However, a detailed analysis of anesthetic effects on ventral motor networks is lacking. We delivered isoflurane, desflurane, or propofol during NMDA/5-HT-induced, or noxious tail stimulus-evoked, fictive locomotion in neonatal rat isolated spinal cords. Anesthetics changed the frequency, amplitude, and regularity of fictive locomotion with little effect on phase-lag. Isoflurane abolished pharmacologically-induced versus noxious stimulus-induced motor output at similar concentrations. Propofol abolished pharmacologically-induced fictive locomotion through a γ-aminobutyric acid type A-receptor mechanism. Anesthetic effects on pharmacologically-elicted fictive locomotion appear clinically-relevant, and support a ventral horn immobilizing effect on locomotor rhythm generation.
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Bullinger KL, Nardelli P, Pinter MJ, Alvarez FJ, Cope TC. Permanent central synaptic disconnection of proprioceptors after nerve injury and regeneration. II. Loss of functional connectivity with motoneurons. J Neurophysiol 2011; 106:2471-85. [PMID: 21832030 DOI: 10.1152/jn.01097.2010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Regeneration of a cut muscle nerve fails to restore the stretch reflex, and the companion paper to this article [Alvarez FJ, Titus-Mitchell HE, Bullinger KL, Kraszpulski M, Nardelli P, Cope TC. J Neurophysiol (August 10, 2011). doi:10.1152/jn.01095.2010] suggests an important central contribution from substantial and persistent disassembly of synapses between regenerated primary afferents and motoneurons. In the present study we tested for physiological correlates of synaptic disruption. Anesthetized adult rats were studied 6 mo or more after a muscle nerve was severed and surgically rejoined. We recorded action potentials (spikes) from individual muscle afferents classified as IA like (*IA) by several criteria and tested for their capacity to produce excitatory postsynaptic potentials (EPSPs) in homonymous motoneurons, using spike-triggered averaging (STA). Nearly every paired recording from a *IA afferent and homonymous motoneuron (93%) produced a STA EPSP in normal rats, but that percentage was only 17% in rats with regenerated nerves. In addition, the number of motoneurons that produced aggregate excitatory stretch synaptic potentials (eSSPs) in response to stretch of the reinnervated muscle was reduced from 100% normally to 60% after nerve regeneration. The decline in functional connectivity was not attributable to synaptic depression, which returned to its normally low level after regeneration. From these findings and those in the companion paper, we put forward a model in which synaptic excitation of motoneurons by muscle stretch is reduced not only by misguided axon regeneration that reconnects afferents to the wrong receptor type but also by retraction of synapses with motoneurons by spindle afferents that successfully reconnect with spindle receptors in the periphery.
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Affiliation(s)
- Katie L Bullinger
- Dept. of Neuroscience, Cell Biology, and Physiology, Wright State Univ. School of Medicine, 3640 Colonel Glenn Hwy., Dayton OH 45435, USA
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Love L, Egger C, Rohrbach B, Cox S, Hobbs M, Doherty T. The effect of ketamine on the MACBAR of sevoflurane in dogs. Vet Anaesth Analg 2011; 38:292-300. [DOI: 10.1111/j.1467-2995.2011.00616.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Identification and characterization of anesthetic targets by mouse molecular genetics approaches. Can J Anaesth 2010; 58:178-90. [PMID: 21174184 DOI: 10.1007/s12630-010-9414-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 10/26/2010] [Indexed: 01/01/2023] Open
Abstract
PURPOSE It is now generally accepted that proteins are the primary targets of general anesthetics. However, the demonstration that the activity of a protein is altered by general anesthetics at clinically relevant concentrations in vitro does not provide direct evidence that this target mediates pharmacological actions of general anesthetics. Here we report on advances that have been made in identifying the contribution of individual ligand-gated ion channels to defined anesthetic endpoints using molecular mouse genetics. PRINCIPAL FINDINGS Gamma-aminobutyric acid (GABA)(A) receptor subtypes defined by the presence of the α1, α4, α5, β2, and β3 subunits and two-pore domain potassium channels (TASK-1, TASK-3, and TREK) have been discovered to mediate, at least in part, the hypnotic, immobilizing or amnestic actions of intravenous and volatile general anesthetics. Moreover, using tissues from genetically modified mice, specific functions of GABA(A) receptor subtypes in cortical and spinal neuronal networks were identified. CONCLUSION Genetically modified mice have been very useful for research on mechanisms of anesthesia and have contributed to the functional identification of general anesthetic targets and of the role of these targets in neuronal networks.
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Scheepers PA, Levin A. Movement of the patient and the concept of minimum alveolar concentration (MAC). SOUTHERN AFRICAN JOURNAL OF ANAESTHESIA AND ANALGESIA 2010. [DOI: 10.1080/22201173.2010.10872686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Van LOON JPAM, Van OOSTROM H, DOORNENBAL A, HELLEBREKERS LJ. Lumbosacral spinal cord somatosensory evoked potentials for quantification of nociception in horses. Equine Vet J 2010; 42:255-60. [DOI: 10.1111/j.2042-3306.2009.00023.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Antognini JF. Anesthetic action: the importance of the spinal cord to immobility. Vet J 2010; 187:151-2. [PMID: 20226701 DOI: 10.1016/j.tvjl.2010.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 02/06/2010] [Indexed: 10/19/2022]
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Spadavecchia C, Levionnois O, Kronen P, Andersen OK. The effects of isoflurane minimum alveolar concentration on withdrawal reflex activity evoked by repeated transcutaneous electrical stimulation in ponies. Vet J 2010; 183:337-44. [DOI: 10.1016/j.tvjl.2008.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 12/22/2008] [Accepted: 12/22/2008] [Indexed: 11/25/2022]
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Brainstem regions affecting minimum alveolar concentration and movement pattern during isoflurane anesthesia. Anesthesiology 2010; 112:316-24. [PMID: 20098133 DOI: 10.1097/aln.0b013e3181c81319] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Spinal transection or selective delivery of volatile anesthetics to the spinal cord reduces minimum alveolar concentration (MAC), whereas precollicular decerebration does not. The authors sought to determine which brainstem regions influence anesthetic requirements and movement responses with isoflurane. METHODS Movement (biceps femoris electromyogram) and MAC were measured in adult rats before and after decerebration at the precollicular, mid-collicular, pontine or medullary level, or decerebellation. Additional experiments assessed the effects of lidocaine inactivation of the mesencephalic locomotor region on MAC and the effects of isoflurane on nociceptive neuronal responses in this region. RESULTS Transections placed at the level of the mid-colliculus, rostral pons, and pontomedullary junction significantly reduced MAC by approximately 10, 40, and 45%, respectively. MAC was decreased 9% after mid-medullary transections that were placed caudal to the nucleus raphe magnus but rostral to the dorsal reticular nucleus; however, only weak, single movements occurred. Caudal medullary transections at the obex decreased MAC by 60%. Bilateral inactivation of the mesencephalic locomotor region with lidocaine caused a reversible, 32% decrease in MAC and reduced the number and amplitude of movements at sub-MAC isoflurane concentrations. Neuronal responses of mesencephalic locomotor region neurons to supramaximal noxious tail clamp were reduced by 87% by 1.2 MAC isoflurane. CONCLUSIONS The authors conclude that the mesencephalic locomotor region influences anesthetic requirements and promotes repetitive movement with sub-MAC isoflurane by facilitating ventral spinal locomotor circuits, where anesthetics seem to exert their key immobilizing effects. However, net brainstem influences on MAC seem to result from interaction among descending nociceptive and locomotor modulatory pathways.
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Petrenko AB, Yamakura T, Kohno T, Sakimura K, Baba H. Reduced immobilizing properties of isoflurane and nitrous oxide in mutant mice lacking the N-methyl-D-aspartate receptor GluR(epsilon)1 subunit are caused by the secondary effects of gene knockout. Anesth Analg 2010; 110:461-5. [PMID: 19933527 DOI: 10.1213/ane.0b013e3181c76e73] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Until recently, the N-methyl-D-aspartate (NMDA) receptor was considered to possibly mediate the immobility produced by inhaled anesthetics such as isoflurane and nitrous oxide. However, new evidence suggests that the role of this receptor in abolition of the movement response may be less important than previously thought. To provide further evidence supporting or challenging this view, we examined the anesthetic potencies of isoflurane and nitrous oxide in genetically modified animals with established NMDA receptor dysfunction caused by GluRepsilon1 subunit knockout. METHODS The immobilizing properties of inhaled anesthetics in mice quantitated by the minimum alveolar anesthetic concentration (MAC) were evaluated using the classic tail clamp method. RESULTS Compared with wild-type controls, NMDA receptor GluRepsilon1 subunit knockout mice displayed larger isoflurane MAC values indicating a resistance to the immobilizing action of isoflurane. Knockout mice were previously shown to have enhanced monoaminergic tone as a result of genetic manipulation, and this increase in MAC could be abolished in our experiments by pretreatment with the serotonin 5-hydroxytryptamine type 2A receptor antagonist ketanserin or with the dopamine D2 receptor antagonist droperidol at doses that did not affect MAC values in wild-type animals. Mutant mice also displayed resistance to the isoflurane MAC-sparing effect of nitrous oxide, but this resistance was similarly abolished by ketanserin and droperidol. Thus, resistance to the immobilizing action of inhaled anesthetics in knockout mice seems to be secondary to increased monoaminergic activation after knockout rather than a direct result of impaired NMDA receptor function. CONCLUSIONS Our results confirm recent findings indicating no critical contribution of NMDA receptors to the immobility induced by isoflurane and nitrous oxide. In addition, they demonstrate the ability of changes secondary to genetic manipulation to affect the results obtained in global knockout studies.
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Affiliation(s)
- Andrey B Petrenko
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi, Niigata 951-8510, Japan.
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Zhang Y, Guzinski M, Eger EI, Laster MJ, Sharma M, Harris RA, Hemmings HC. Bidirectional modulation of isoflurane potency by intrathecal tetrodotoxin and veratridine in rats. Br J Pharmacol 2010; 159:872-8. [PMID: 20105175 DOI: 10.1111/j.1476-5381.2009.00583.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Results from several studies point to voltage-gated Na(+) channels as potential mediators of the immobility produced by inhaled anaesthetics. We hypothesized that the intrathecal administration of tetrodotoxin, a drug that blocks Na(+) channels, should enhance anaesthetic potency, and that concurrent administration of veratridine, a drug that augments Na(+) channel opening, should reverse the increase in potency. EXPERIMENTAL APPROACH We measured the change in isoflurane potency for reducing movement in response to a painful stimulus as defined by MAC (minimum alveolar concentration of anaesthetic required to abolish movement in 50% of subjects) caused by intrathecal infusion of various concentrations of tetrodotoxin into the lumbothoracic subarachnoid space of rats, and the change in MAC caused by the administration of a fixed dose of tetrodotoxin plus various doses of intrathecal veratridine. KEY RESULTS Intrathecal infusion of tetrodotoxin (0.078-0.63 microM) produced a reversible dose-related decrease in MAC, of more than 50% at the highest concentration. Intrathecal co-administration of veratridine (1.6-6.4 microM) reversed this decrease in a dose-related manner, with nearly complete reversal at the highest veratridine dose tested. CONCLUSIONS AND IMPLICATIONS Intrathecal administration of tetrodotoxin increases isoflurane potency (decreases isoflurane MAC), and intrathecal administration of veratridine counteracts this effect in vivo. These findings are consistent with a role for voltage-gated Na(+) channel blockade in the immobility produced by inhaled anaesthetics.
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Affiliation(s)
- Y Zhang
- Department of Anesthesiology, Fuwai Hospital and Cardiovascular Institute, Beijing, China
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Jinks SL, Carstens E, Antognini JF. Nitrous oxide-induced analgesia does not influence nitrous oxide's immobilizing requirements. Anesth Analg 2009; 109:1111-6. [PMID: 19762738 DOI: 10.1213/ane.0b013e3181b5a2a7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Nitrous oxide (N(2)O) acts on supraspinal noradrenergic neurons to produce analgesia, but it is unclear if analgesia contributes to N(2)O's immobilizing effects. We tested the hypothesis that N(2)O minimum alveolar anesthetic concentration (MAC) is unchanged after selective ablation of supraspinal noradrenergic neurons, or in naïve animals at N(2)O exposure timepoints when analgesia is absent. METHODS We determined tailflick latency (TFL) and hindpaw withdrawal latency (HPL) under 70% N(2)O, N(2)O MAC, and isoflurane MAC before and after intracerebroventricular injections of anti-dopamine-beta hydroxylase conjugated to saporin (SAP-DBH; n = 7), or a control antibody conjugated to saporin (n = 5). In a separate group of naive rats (n = 8), N(2)O MAC was determined at 25-45 min after initiation of N(2)O exposure (during peak analgesia) and again at 120-140 min (after TFL and HPL returned to baseline). RESULTS After 30 min of N(2)O exposure, TFL and HPL increased significantly but declined back to baseline within 120 min. N(2)O did not produce analgesia in rats that received SAP-DBH. However, N(2)O and isoflurane MAC were not significantly different between SAP-DBH and control-injected animals (Mean +/- sd for N(2)O: 1.7 +/- 0.1 atm vs 1.7 +/- 0.2 atm; isofurane: 1.6 +/- 0.2% vs 1.7 +/- 0.2%). In naïve animals, N(2)O MAC was not different at the 30 min period compared with the 120 min period (1.8 +/- 0.1 atm vs 1.8 +/- 0.2 atm). CONCLUSIONS Destroying brainstem noradrenergic neurons or prolonged exposure to N(2)O removes its analgesic effects, but does not change MAC. The immobilizing mechanism of N(2)O is independent from its analgesic effects.
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Affiliation(s)
- Steven L Jinks
- Department of Anesthesiology and Pain Medicine, University of California School of Medicine, Davis, CA 95616, USA.
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Effect of ketamine on the limb withdrawal reflex evoked by transcutaneous electrical stimulation in ponies anaesthetised with isoflurane. Vet J 2009; 186:304-11. [PMID: 19748807 DOI: 10.1016/j.tvjl.2009.08.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 06/15/2009] [Accepted: 08/15/2009] [Indexed: 11/24/2022]
Abstract
The purpose of this study was to evaluate the anti-nociceptive activity of ketamine and isoflurane in horses using a limb withdrawal reflex (WR) model. Single and repeated stimulations were applied to the digital nerve of the left forelimb in ponies anaesthetised with isoflurane before, during and after intravenous administration of racemic ketamine. Surface electromyographic activity was recorded from the deltoid muscle. Higher stimulation intensity was required to evoke a reflex during ketamine administration. Furthermore, the amplitudes of response to stimulations were significantly and dose-dependently depressed and a flattening of the stimulus-response curves was observed. The reflex activity recovered partially once the ketamine infusion finished. The results demonstrated that the limb WR can be used to quantify the temporal effect of ketamine on the sensory-motor processing in ponies anaesthetised with isoflurane.
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Barter LS, Carstens EE, Jinks SL, Antognini JF. Rat dorsal horn nociceptive-specific neurons are more sensitive than wide dynamic range neurons to depression by immobilizing doses of volatile anesthetics: an effect partially reversed by the opioid receptor antagonist naloxone. Anesth Analg 2009; 109:641-7. [PMID: 19608842 DOI: 10.1213/ane.0b013e3181a9770f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND The mechanism and site of action within the spinal cord by which volatile anesthetics produce immobility are not well understood. Little work has been done directly comparing anesthetic effects on neurons with specific functional characteristics that mediate transfer of nociceptive information within the spinal cord. METHODS Adult male rats were anesthetized and prepared for extracellular single-unit recordings from the lumbar dorsal horn. Nociceptive-specific (NS) and wide dynamic range (WDR) neurons were identified and noxious heat-evoked neuronal spike rates evaluated at 0.8 and 1.2 anesthetic minimum alveolar anesthetic concentration (MAC) halothane or isoflurane. In another group, noxious heat-evoked responses from NS neurons were evaluated at 0.8, 1.2 MAC halothane, and 1.2 MAC halothane plus IV naloxone (0.1 mg/kg). RESULTS Increasing halothane from 0.8 to 1.2 MAC reduced the heat-evoked neuronal responses of NS neurons (n = 9) from 827 +/- 122 (mean +/- se) to 343 +/- 48 spikes/min (P < 0.05) but not WDR neurons (n = 9), 617 +/- 79 to 547 +/- 78 spikes/min. Increasing isoflurane from 0.8 to 1.2 MAC reduced the heat-evoked neuronal response of NS neurons (n = 9) from 890 +/- 339 to 188 +/- 97 spikes/min (P < 0.05) but did not alter the response of WDR neurons (n = 9) in which evoked spike rate went from 576 +/- 132 to 601 +/- 119 spikes/min. In a separate group, the response of NS neurons went from 282 +/- 60 to 74 +/- 32 spikes/min (P < 0.05) when halothane was increased from 0.8 to 1.2 MAC. IV administration of naloxone increased the heat-evoked response to 155 +/- 46 spikes/min (P < 0.05). CONCLUSIONS NS but not WDR neurons in the lumbar dorsal horn are depressed by peri-MAC increases of halothane and isoflurane. This depression, at least with halothane, can be partially reversed by the opioid antagonist naloxone. Given that opioid receptors are not likely involved in the mechanisms by which volatile anesthetics produce immobility, this suggests that, although the neuronal depression is of substantial magnitude and occurs concurrent to the production of immobility, it may not play a major role in the production of this anesthetic end point.
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Affiliation(s)
- Linda S Barter
- Departments of Anesthesiology and Pain Medicine, University of California, Davis, California 95616, USA.
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van Loon JPAM, Stienen PJ, Doornenbal A, Hellebrekers LJ. Use of epidurally derived evoked potentials for quantification of caudal nociception in ponies. Am J Vet Res 2009; 70:813-9. [DOI: 10.2460/ajvr.70.7.813] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kungys G, Kim J, Jinks SL, Atherley RJ, Antognini JF. Propofol produces immobility via action in the ventral horn of the spinal cord by a GABAergic mechanism. Anesth Analg 2009; 108:1531-7. [PMID: 19372332 DOI: 10.1213/ane.0b013e31819d9308] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND We investigated the actions of propofol and isoflurane on nociceptive responses of neurons in the spinal cord. METHODS We determined nociceptive responses of lumbar neurons in the dorsal horn (<1200 microm) and ventral horn (>1200 microm) of decerebrate rats before and during propofol (1 effective dose, ED(50)) or isoflurane (1 minimum alveolar concentration) anesthesia. During recording of ventral horn neurons, we administered picrotoxin by infusion to determine whether isoflurane and propofol differed in their effects at the gamma aminobutyric acid (GABA) Type A receptors. We also determined whether decerebration altered propofol requirements to produce immobility. RESULTS Decerebration did not affect propofol requirements. The ED(50) for propofol was 497 +/- 58 microg x kg(-1) x min(-1) in intact rats and 420 +/- 65 microg x kg(-1) x min(-1) in decerebrated rats (P > 0.05), with corresponding propofol blood concentrations of 8.1 +/- 1.1 microg/mL and 7.3 +/- 1.1 microg/mL, respectively (P > 0.05). Propofol did not significantly depress dorsal horn neurons, but isoflurane depressed the responses to 56% of control (P < 0.05). Propofol depressed ventral horn neurons to 47% of control, whereas isoflurane depressed ventral horn neurons to 20% of control. Picrotoxin significantly reversed the depressant effect of propofol on ventral horn neuronal responses (79% of control, not significantly different from control). Pic- rotoxin, however, had no effect on isoflurane's depression of ventral horn neuronal responses (26% of control). CONCLUSIONS Propofol acts in the spinal cord to produce immobility. This depressive effect occurs in the ventral horn and is mediated mainly by GABA(A) receptors. Isoflurane also depresses neurons in the ventral horn; however, isoflurane actions at the GABA(A) receptor are either weak or overridden by other effects in the ventral horn.
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Affiliation(s)
- Gudrun Kungys
- Department of Anesthesiology and Pain Medicine, University of California, Davis, California 95616, USA
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Wang Y, Wu J, Lin Q, Nauta H, Yue Y, Fang L. Effects of general anesthetics on visceral pain transmission in the spinal cord. Mol Pain 2008; 4:50. [PMID: 18973669 PMCID: PMC2584043 DOI: 10.1186/1744-8069-4-50] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 10/30/2008] [Indexed: 12/30/2022] Open
Abstract
Current evidence suggests an analgesic role for the spinal cord action of general anesthetics; however, the cellular population and intracellular mechanisms underlying anti-visceral pain by general anesthetics still remain unclear. It is known that visceral nociceptive signals are transmited via post-synaptic dorsal column (PSDC) and spinothalamic tract (STT) neuronal pathways and that the PSDC pathway plays a major role in visceral nociception. Animal studies report that persistent changes including nociception-associated molecular expression (e.g. neurokinin-1 (NK-1) receptors) and activation of signal transduction cascades (such as the protein kinase A [PKA]-c-AMP-responsive element binding [CREB] cascade)-in spinal PSDC neurons are observed following visceral pain stimulation. The clinical practice of interruption of the spinal PSDC pathway in patients with cancer pain further supports a role of this group of neurons in the development and maintenance of visceral pain. We propose the hypothesis that general anesthetics might affect critical molecular targets such as NK-1 and glutamate receptors, as well as intracellular signaling by CaM kinase II, protein kinase C (PKC), PKA, and MAP kinase cascades in PSDC neurons, which contribute to the neurotransmission of visceral pain signaling. This would help elucidate the mechanism of antivisceral nociception by general anesthetics at the cellular and molecular levels and aid in development of novel therapeutic strategies to improve clinical management of visceral pain.
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Affiliation(s)
- Yun Wang
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, PR China.
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Grasshoff C, Netzhammer N, Schweizer J, Antkowiak B, Hentschke H. Depression of spinal network activity by thiopental: Shift from phasic to tonic GABAA receptor-mediated inhibition. Neuropharmacology 2008; 55:793-802. [DOI: 10.1016/j.neuropharm.2008.06.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 06/02/2008] [Accepted: 06/16/2008] [Indexed: 12/31/2022]
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Volatile anesthetic effects on midbrain-elicited locomotion suggest that the locomotor network in the ventral spinal cord is the primary site for immobility. Anesthesiology 2008; 108:1016-24. [PMID: 18497602 DOI: 10.1097/aln.0b013e3181730297] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Volatile anesthetics produce immobility primarily by action in the spinal cord; however, anesthetic effects among different neuronal classes located in different spinal regions, and how they relate to immobility, are not understood. METHODS In decerebrated rats, effects of isoflurane and halothane on movement elicited by electrical microstimulation of the mesencephalic locomotor region (MLR) were assessed in relation to minimum alveolar concentration (MAC). Anesthetic effects on step frequency and isometric limb force were measured. The authors also examined effects of MLR stimulation on responses of nociceptive dorsal horn neurons and limb force responses to tail clamp. RESULTS Mean isoflurane requirements to block MLR-elicited stepping were slightly but significantly greater than MAC by 10%. Mean halothane requirements to block MLR-elicited stepping were greater than those for isoflurane and exceeded MAC by 20%. From 0.4 to 1.3 MAC (but not 0.0 to 0.4 MAC), there was a dose-dependent reduction in the frequency and force of hind limb movements elicited by MLR stimulation during both anesthetics. MLR stimulation inhibited noxious stimulus evoked responses of dorsal horn neurons by approximately 80%. Aptly, MLR stimulation produced analgesia that outlasted the midbrain stimulus by at least 15 s, as indicated by an 81% reduction in hind limb force elicited noxious tail clamp. CONCLUSIONS Because electrical stimulation of the MLR elicits movement independent of dorsal horn activation, the immobilizing properties of isoflurane and halothane are largely independent of action in the dorsal horn. The results suggest that volatile anesthetics produce immobility mainly by action on ventral spinal locomotor networks.
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Sanders RD, Xu J, Shu Y, Fidalgo A, Ma D, Maze M. General anesthetics induce apoptotic neurodegeneration in the neonatal rat spinal cord. Anesth Analg 2008; 106:1708-11. [PMID: 18499598 DOI: 10.1213/ane.0b013e3181733fdb] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Exposure to anesthetics triggers apoptotic neurodegeneration in the neonatal rat brain; whether neuronal apoptosis also occurs in the spinal cord, a crucial target for analgesic and anesthetic drugs, is unknown. METHODS We exposed 7-day-old rats were exposed to air or 75% nitrous oxide + 0.75% isoflurane in oxygen for 6 h (n = 19 per group). Caspase-3 immunoreactivity was evaluated in the lumbar spinal cord at the end of the gas exposure (n = 3 per group). Developmental nociceptive responses were tested using tail flick latencies on postnatal days 8, 15, and 30 (n = 3 per group). Motor responses were evaluated using the rotarod on postnatal day 30 (n = 7 per group). RESULTS Isoflurane plus nitrous oxide increased the numbers of caspase-3 positive neurons in the spinal cord (P < 0.01). Despite a preponderance of the injury in the ventral horn of the spinal cord, motor impairment did not occur (P > 0.05). No functional effect on nociception was observed at the three developmental stages tested (P > 0.05). CONCLUSIONS Anesthesia induces apoptosis in the neonatal rat spinal cord; however, the functional consequences of this injury, if any, remain obscure. Neither motor nor nociceptive responses were affected by anesthetic treatment. Nonetheless, further investigation is required as regional anesthetic techniques may also trigger neuroapoptosis in the spinal cord with unknown potency.
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Affiliation(s)
- Robert D Sanders
- Department of Anaesthetics, Pain Medicine and Intensive Care, Imperial College London, Chelsea & Westerminster Hospital, London, UK
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Yao A, Kim J, Atherley R, Jinks SL, Carstens E, Shargh S, Sulger A, Antognini JF. The effects of aromatic anesthetics on dorsal horn neuronal responses to noxious stimulation. Anesth Analg 2008; 106:1759-64. [PMID: 18499606 DOI: 10.1213/ane.0b013e3181732ee3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Gamma-aminobutyric acid type A receptor potentiation and/or N-methyl-d-aspartate (NMDA) receptor inhibition might explain the anesthetic properties of fluorinated aromatic compounds. We hypothesized that depression of dorsal horn neuronal responses to noxious stimulation would correlate with the magnitude of effect of benzene (BNZ), o-difluorobenzene, and hexafluorobenzene (HFB) on NMDA receptors. METHODS Rats were anesthetized with desflurane. A T13-L1 laminectomy allowed extracellular recording of neuronal activity from the lumbar spinal cord. After discontinuing desflurane administration, MAC for each aromatic anesthetic was determined. A 5-s noxious mechanical stimulus was then applied to the hindpaw receptive field of nociceptive dorsal horn neurons, and single-neuron responses were recorded at 0.8 and 1.2 MAC. These responses were also recorded in decerebrate rats receiving BNZ and HFB at 0-1.2 MAC. RESULTS In intact rats, depression of responses of dorsal horn neurons to noxious stimulation by peri-MAC increases in BZN, o-difluorobenzene, and HFB correlated directly with their in vitro capacity to block NMDA receptors. In decerebrate rats, 1.2 MAC BNZ depressed nociceptive responses by 60%, with a further percentage decrease continuing from 0.8 to 1.2 MAC approximately equal to that found in intact rats. In decerebrate rats, HFB caused a progressive dose-related decrease in MAC (maximum 25%), but in intact rats, an increase from 0.8 to 1.2 neuronal response caused an (insignificant) increase in neuronal response. CONCLUSIONS The findings in intact rats suggest that NMDA blockade contributes to the depression of dorsal horn neurons to nociceptive stimulation by fluorinated aromatic anesthetics. These results, combined with the additional findings in decerebrate rats, suggest that supraspinal effects (perhaps on gamma-aminobutyric acid type A receptors) may have a supraspinal facilitatory effect on nociception for HFB.
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Affiliation(s)
- Aubrey Yao
- Department of Anesthesiology and Pain Medicine, University of California, Davis, CA 95616, USA
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