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Auvity S, Vodovar D, Goutal S, Cisternino S, Chevillard L, Soyer A, Bottlaender M, Caillé F, Mégarbane B, Tournier N. Brain PET imaging using 11C-flumazenil and 11C-buprenorphine does not support the hypothesis of a mutual interaction between buprenorphine and benzodiazepines at the neuroreceptor level. J Cereb Blood Flow Metab 2024; 44:449-458. [PMID: 38097513 PMCID: PMC10870960 DOI: 10.1177/0271678x231221040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 11/20/2023] [Accepted: 11/20/2023] [Indexed: 02/16/2024]
Abstract
Among opioids, buprenorphine presents a favorable safety profile with a limited risk of respiratory depression. However, fatalities have been reported when buprenorphine is combined to a benzodiazepine. Potentiation of buprenorphine interaction with opioid receptors (ORs) with benzodiazepines, and/or vice versa, is hypothesized to explain this drug-drug interaction (DDI). The mutual DDI between buprenorphine and benzodiazepines was investigated at the neuroreceptor level in nonhuman primates (n = 4 individuals) using brain PET imaging and kinetic modelling. The binding potential (BPND) of benzodiazepine receptor (BzR) was assessed using 11C-flumazenil PET imaging before and after administration of buprenorphine (0.2 mg, i.v.). Moreover, the brain kinetics and receptor binding of buprenorphine were investigated in the same individuals using 11C-buprenorphine PET imaging before and after administration of diazepam (10 mg, i.v.). Outcome parameters were compared using a two-way ANOVA. Buprenorphine did not impact the plasma nor brain kinetics of 11C-flumazenil. 11C-flumazenil BPND was unchanged following buprenorphine exposure, in any brain region (p > 0.05). Similarly, diazepam did not impact the plasma or brain kinetics of 11C-buprenorphine. 11C-buprenorphine volume of distribution (VT) was unchanged following diazepam exposure, in any brain region (p > 0.05). To conclude, our PET imaging findings do not support a neuropharmacokinetic or neuroreceptor-related mechanism of the buprenorphine/benzodiazepine interaction.
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Affiliation(s)
- Sylvain Auvity
- Faculté de Pharmacie, Université Paris Cité, Inserm, UMRS-1144, Optimisation Thérapeutique en Neuropsychopharmacologie, 75006 Paris, France
| | - Dominique Vodovar
- Faculté de Pharmacie, Université Paris Cité, Inserm, UMRS-1144, Optimisation Thérapeutique en Neuropsychopharmacologie, 75006 Paris, France
- Réanimation Médicale et Toxicologique, Hôpital Lariboisière, Fédération de Toxicologie (APHP), 75010, Paris
| | - Sébastien Goutal
- Université Paris-Saclay, Inserm, CNRS, CEA, Laboratoire d’Imagerie Biomédicale Multimodale (BioMaps), Orsay, France
| | - Salvatore Cisternino
- Faculté de Pharmacie, Université Paris Cité, Inserm, UMRS-1144, Optimisation Thérapeutique en Neuropsychopharmacologie, 75006 Paris, France
| | - Lucie Chevillard
- Faculté de Pharmacie, Université Paris Cité, Inserm, UMRS-1144, Optimisation Thérapeutique en Neuropsychopharmacologie, 75006 Paris, France
| | - Amélie Soyer
- Université Paris-Saclay, Inserm, CNRS, CEA, Laboratoire d’Imagerie Biomédicale Multimodale (BioMaps), Orsay, France
| | - Michel Bottlaender
- Université Paris-Saclay, Inserm, CNRS, CEA, Laboratoire d’Imagerie Biomédicale Multimodale (BioMaps), Orsay, France
| | - Fabien Caillé
- Université Paris-Saclay, Inserm, CNRS, CEA, Laboratoire d’Imagerie Biomédicale Multimodale (BioMaps), Orsay, France
| | - Bruno Mégarbane
- Faculté de Pharmacie, Université Paris Cité, Inserm, UMRS-1144, Optimisation Thérapeutique en Neuropsychopharmacologie, 75006 Paris, France
- Réanimation Médicale et Toxicologique, Hôpital Lariboisière, Fédération de Toxicologie (APHP), 75010, Paris
| | - Nicolas Tournier
- Université Paris-Saclay, Inserm, CNRS, CEA, Laboratoire d’Imagerie Biomédicale Multimodale (BioMaps), Orsay, France
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Farzana N, Tewari P, Sureka S, Dixit A. Parosmia and dysgeusia after intravenous propofol-based general anesthesia: A case report. Ann Card Anaesth 2022; 25:112-115. [PMID: 35075034 PMCID: PMC8865345 DOI: 10.4103/aca.aca_93_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Various drugs, including anesthetic agents, can cause parosmia in the perioperative period. There are reported cases of patients with alterations of smell and taste due to local anesthetics, nerve damage, or as a side effect of general anesthesia. We present a case of a 58-year-old male who developed parosmia and dysgeusia in the postoperative period after radical nephrectomy and inferior vena cava thrombectomy. The anesthetics used were fentanyl and propofol for general anesthesia and ropivacaine for epidural analgesia. Clinical examination did not reveal any pathology.
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Varnäs K, Finnema SJ, Johnström P, Arakawa R, Halldin C, Eriksson LI, Farde L. Effects of sevoflurane anaesthesia on radioligand binding to monoamine oxidase-B in vivo. Br J Anaesth 2020; 126:238-244. [PMID: 33036760 PMCID: PMC8258980 DOI: 10.1016/j.bja.2020.08.052] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/24/2020] [Accepted: 08/31/2020] [Indexed: 11/28/2022] Open
Abstract
Background The molecular actions underlying the clinical effects of inhaled anaesthetics such as sevoflurane and isoflurane are not fully understood. Unexpected observations in positron emission tomography (PET) studies with [11C]AZD9272, a metabotropic glutamate receptor 5 (mGluR5) radioligand with possible affinity for monoamine oxidase-B (MAO-B), suggest that its binding is sensitive to anaesthesia with sevoflurane. The objective of the present study was to assess the effects of sevoflurane anaesthesia on the binding of [11C]AZD9272 and of [11C]L-deprenyl-D2, a radioligand selective for MAO-B in non-human primates (NHPs). Methods Altogether, 12 PET measurements were conducted with a high-resolution research tomograph using the ligands [11C]AZD9272 or [11C]L-deprenyl-D2 in six cynomolgus monkeys anaesthetised with sevoflurane or ketamine/xylazine. Results The specific binding of [11C]AZD9272 and [11C]L-deprenyl-D2 was markedly reduced during anaesthesia with sevoflurane compared with ketamine/xylazine. The reduction was 80–90% (n=3) for [11C]AZD9272 and 77–80% (n=3) for [11C]L-deprenyl-D2. Conclusions Sevoflurane anaesthesia inhibited radioligand binding to MAO-B in the primate brain. The observation of lower MAO-B binding at clinically relevant concentrations of sevoflurane warrants further exploration of the potential role of MAO-B related mechanisms in regulation of systemic blood pressure during anaesthesia.
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Affiliation(s)
- Katarina Varnäs
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden.
| | - Sjoerd J Finnema
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Peter Johnström
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden; PET Science Centre, Precision Medicine and Biosamples, R&D Oncology, AstraZeneca, Karolinska Institutet, Stockholm, Sweden
| | - Ryosuke Arakawa
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Lars I Eriksson
- Perioperative Medicine and Intensive Care, Section for Anesthesiology and Intensive Care Medicine, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Lars Farde
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
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Scheinin H, Alkire EC, Scheinin A, Alkire MT, Kantonen O, Långsjö J. Using Positron Emission Tomography in Revealing the Mystery of General Anesthesia: Study Design Challenges and Opportunities. Methods Enzymol 2018; 603:279-303. [PMID: 29673531 DOI: 10.1016/bs.mie.2018.01.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Functional neuroimaging with positron emission tomography (PET) is one of the cornerstones for studying the central nervous system effects of general anesthetics and anesthesia mechanisms. General anesthesia offers a unique and safe way to directly manipulate consciousness, and can thus be used as a powerful research tool to study the neurobiology of human consciousness. In this chapter, we will address the possibilities of PET imaging in revealing the mysteries of general anesthesia and anesthetic induced unconsciousness and summarize some of the recent advancements in the field. Importantly, we will discuss possible ways to separate brain activity changes associated with the changing level of consciousness from the concentration or dose-dependent direct or indirect drug effects on the brain. We will try to demonstrate how state-of-the-art clinical pharmacology, use of specific anesthetic drugs, and innovative study design solutions could be utilized.
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Affiliation(s)
- Harry Scheinin
- Turku PET Centre, University of Turku and the Hospital District of Southwest Finland, Turku, Finland; Turku University Hospital, Turku, Finland; Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Turku, Finland.
| | - Emilee C Alkire
- The Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
| | - Annalotta Scheinin
- Turku PET Centre, University of Turku and the Hospital District of Southwest Finland, Turku, Finland; Turku University Hospital, Turku, Finland
| | - Michael T Alkire
- The Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States; VA Long Beach Healthcare System, Long Beach, CA, United States
| | - Oskari Kantonen
- Turku University Hospital, Turku, Finland; The Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
| | - Jaakko Långsjö
- Turku PET Centre, University of Turku and the Hospital District of Southwest Finland, Turku, Finland; Tampere University Hospital, Tampere, Finland
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Du W, Xu Z, Wang W, Liu Z. A case of anosmia and hypogeusia as a complication of propofol. J Anesth 2018; 32:293-296. [PMID: 29476257 DOI: 10.1007/s00540-018-2461-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 01/27/2018] [Indexed: 11/24/2022]
Abstract
Anesthetics represent an uncommon cause of taste and smell disorders. We describe a case of anosmia and hypogeusia for 6 weeks after recovery from a uterine curettage operation in a 32-year-old woman. The case is unusual because propofol was the only anesthetic used during surgery and anesthesia. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed no abnormality. This case may highly suggest that propofol could induce smell and taste disorders.
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Affiliation(s)
- Weijia Du
- Department of Anesthesiology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 201204, China
| | - Zhendong Xu
- Department of Anesthesiology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 201204, China
| | - Wenjing Wang
- Department of Radiology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 201204, China
| | - Zhiqiang Liu
- Department of Anesthesiology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 201204, China.
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Saravanan B, Kundra P, Mishra SK, Surianarayanan G, Parida PK. Effect of anaesthetic agents on olfactory threshold and identification - A single blinded randomised controlled study. Indian J Anaesth 2018; 62:592-598. [PMID: 30166653 PMCID: PMC6100266 DOI: 10.4103/ija.ija_245_18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background and Aims: Anaesthetics are implicated in cognitive dysfunction, taste and odour deficits in the postoperative period. We aimed to assess the effect of isoflurane, sevoflurane, propofol and regional anaesthesia on the olfactory threshold, olfactory identification and endocrine regulation of associative memory in the postoperative period. Methods: In this observer-blinded randomised controlled study, 164 patients (>50 years) with the American Society of Anesthesiologists I and II status were randomised into one of four groups to receive regional anaesthesia, general anaesthesia with sevoflurane, general anaesthesia with isoflurane and total intravenous anaesthesia with propofol. Hindi Mental State Examination, olfactory threshold and olfactory identification were tested at 12 h preoperatively (T0), at 3 h postoperatively (T1) and at the time of discharge or postoperative day 3 (T2). In addition, serum melatonin levels were estimated at T0 and T1. The olfactory threshold was tested with n-butyl alcohol and olfactory identification with the University of Pennsylvania Smell Identification Test (UPSIT). Data were analysed using the one-way analysis of variance, Kruskal-Wallis or Mann-whitney tests. Results: The olfactory identification scores were lower with patients receiving sevoflurane-based anaesthesia at 3 h postoperatively (T1) when compared to preoperative (T0) (median 19.5 vs. 22; P = 0.01). This was accompanied by a significant postoperative reduction of plasma melatonin levels in sevoflurane group when compared to other groups (17.34 ± 4.8 pg/ml vs 23.2 ± 3.5 pg/ml; P < 0.001). Conclusion: Sevoflurane was associated with short-term olfactory identification impairment with a concomitant reduction in melatonin levels illustrating a possible humoral mechanism.
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Affiliation(s)
- Balachandar Saravanan
- Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Pankaj Kundra
- Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Sandeep Kumar Mishra
- Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Gopalakrishnan Surianarayanan
- Department of Otorhinolaryngology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Pradipta Kumar Parida
- Department of Otorhinolaryngology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
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Abstract
This case report describes a patient, who lost the ability to smell and taste after receiving a propofol-based general anesthesia for a laparoscopic inguinal hernia repair. Immediately after the procedure, the patient had anosmia (loss of smell), ageusia (loss of taste), and light dysphagia. Assessment by an otorhinolaryngologist and the results of a magnetic resonance imaging could not clarify the pathology behind these symptoms. Although there are several plausible explanations for the patient's anosmia and ageusia (eg, cerebral infarcts, nerve damage, chronic sinusitis), the most likely explanation is an uncommon adverse drug reaction to the anesthetic agents used during the procedure.
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Safety and Effectiveness of Endoscopist-Directed Nurse-Administered Sedation during Gastric Endoscopic Submucosal Dissection. Gastroenterol Res Pract 2017; 2017:4723626. [PMID: 28769979 PMCID: PMC5523312 DOI: 10.1155/2017/4723626] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 06/07/2017] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND AIMS Endoscopic submucosal dissection (ESD) is routinely performed in treating gastric neoplasia and requires long-term higher levels of sedation. Endoscopist-directed nurse-administered sedation (EDNAS) has not been well studied in ESD. This study aimed to evaluate the safety and effectiveness of EDNAS for ESD. METHODS Patients treated with ESD for gastric tumors between 2013 and 2015 were retrospectively collected. Patients were divided into a midazolam-treated group (M group) and a midazolam plus propofol-treated group (MP group). Clinical outcome, safety, effectiveness, adverse events of ESD, and adverse events of sedation were analyzed. RESULTS Of 209 collected patients, 83 were in the M group and 126 were in the MP group. Of all patients, 67 patients had the circulatory adverse event during the ESD procedure. Sedation method was the only significant risk factor (M versus MP: 2.17 (1.14-4.15), p = 0.019). In analysis of MP subgroups, 47 patients suffered an adverse event from sedation, and current smoking was the only significant association factor for adverse event (0.15 (0.03-0.68), p = 0.014). CONCLUSIONS In performing ESD, the effect of sedation is reduced in smoking patients. EDNAS may be acceptable for ESD under careful monitoring of vital sign and oxygen saturation.
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Effects of common anesthetic agents on [ 18F]flumazenil binding to the GABA A receptor. EJNMMI Res 2016; 6:80. [PMID: 27826950 PMCID: PMC5101239 DOI: 10.1186/s13550-016-0235-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 10/29/2016] [Indexed: 12/25/2022] Open
Abstract
Background The availability of GABAA receptor binding sites in the brain can be assessed by positron emission tomography (PET) using the radioligand, [18F]flumazenil. However, the brain uptake and binding of this PET radioligand are influenced by anesthetic drugs, which are typically needed in preclinical imaging studies and clinical imaging studies involving patient populations that do not tolerate relatively longer scan times. The objective of this study was to examine the effects of anesthesia on the binding of [18F]flumazenil to GABAA receptors in mice. Methods Brain and whole blood radioactivity concentrations were measured ex vivo by scintillation counting or in vivo by PET in four groups of mice following administration of [18F]flumazenil: awake mice and mice anesthetized with isoflurane, dexmedetomidine, or ketamine/dexmedetomidine. Dynamic PET recordings were obtained for 60 min in mice anesthetized by either isoflurane or ketamine/dexmedetomidine. Static PET recordings were obtained at 25 or 55 min after [18F]flumazenil injection in awake or dexmedetomidine-treated mice acutely anesthetized with isoflurane. The apparent distribution volume (VT*) was calculated for the hippocampus and frontal cortex from either the full dynamic PET scans using an image-derived input function or from a series of ex vivo experiments using whole blood as the input function. Results PET images showed persistence of high [18F]flumazenil uptake (up to 20 % ID/g) in the brains of mice scanned under isoflurane or ketamine/dexmedetomidine anesthesia, whereas uptake was almost indiscernible in late samples or static scans from awake or dexmedetomidine-treated animals. The steady-state VT* was twofold higher in hippocampus of isoflurane-treated mice and dexmedetomidine-treated mice than in awake mice. Conclusions Anesthesia has pronounced effects on the binding and blood-brain distribution of [18F]flumazenil. Consequently, considerable caution must be exercised in the interpretation of preclinical and clinical PET studies of GABAA receptors involving the use of anesthesia.
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Positron Emission Tomography: Basic Principles, New Applications, and Studies Under Anesthesia. Int Anesthesiol Clin 2016; 54:109-28. [PMID: 26655512 DOI: 10.1097/aia.0000000000000090] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Effect of flumazenil on recovery from general anesthesia with isoflurane: A randomized controlled trial☆. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2016. [DOI: 10.1097/01819236-201644010-00003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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12
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El efecto de flumazenil sobre la recuperación de anestesia general con isoflurano: una prueba aleatorizada controlada. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2016. [DOI: 10.1016/j.rca.2015.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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13
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Dias Cicarelli D, Rojas-Álvarez NE, Fuller P, Lacava Pagnocca M, Frerichs E, Martins Benseñor FE. Effect of flumazenil on recovery from general anesthesia with isoflurane: A randomized controlled trial. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2016. [DOI: 10.1016/j.rcae.2015.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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14
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Kaskinoro K, Maksimow A, Georgiadis S, Långsjö J, Scheinin H, Karjalainen P, Jääskeläinen SK. Electroencephalogram reactivity to verbal command after dexmedetomidine, propofol and sevoflurane-induced unresponsiveness. Anaesthesia 2014; 70:190-204. [DOI: 10.1111/anae.12868] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2014] [Indexed: 12/29/2022]
Affiliation(s)
- K. Kaskinoro
- Department of Perioperative Services; Intensive Care and Pain Medicine; Turku University Hospital; Turku Finland
| | - A. Maksimow
- Department of Perioperative Services; Intensive Care and Pain Medicine; Turku University Hospital; Turku Finland
| | - S. Georgiadis
- Department of Applied Physics; University of Eastern Finland; Kuopio Finland
| | - J. Långsjö
- Turku PET Centre; University of Turku; Turku Finland
- Intensive Care Unit; Tampere University Hospital; Tampere Finland
| | - H. Scheinin
- Turku PET Centre and Department of Pharmacology and Clinical Pharmacology; University of Turku; Turku Finland
| | - P. Karjalainen
- Department of Applied Physics; University of Eastern Finland; Kuopio Finland
| | - S. K. Jääskeläinen
- Departments of Clinical Neurophysiology; Turku University Hospital and Clinical Neurophysiology; University of Turku; Turku Finland
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Terada T, Kono S, Konishi T, Miyajima H, Ouchi Y. Altered GABAergic system in the living brain of a patient with spinocerebellar ataxia type 8. J Neurol 2013; 260:3164-6. [PMID: 24162040 DOI: 10.1007/s00415-013-7167-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 10/14/2013] [Accepted: 10/15/2013] [Indexed: 10/26/2022]
Affiliation(s)
- Tatsuhiro Terada
- Department of Biofunctional Imaging, Medical Photonics Research Centre, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, 431-3192, Japan,
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Hines CS, Fujita M, Zoghbi SS, Kim JS, Quezado Z, Herscovitch P, Miao N, Ferraris Araneta MD, Morse C, Pike VW, Labovsky J, Innis RB. Propofol decreases in vivo binding of 11C-PBR28 to translocator protein (18 kDa) in the human brain. J Nucl Med 2012; 54:64-9. [PMID: 23148296 DOI: 10.2967/jnumed.112.106872] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED The PET radioligand (11)C-PBR28 targets translocator protein (18 kDa) (TSPO) and is a potential marker of neuroimmune activation in vivo. Although several patient populations have been studied using (11)C-PBR28, no investigators have studied cognitively impaired patients who would require anesthesia for the PET procedure, nor have any reports investigated the effects that anesthesia may have on radioligand uptake. The purpose of this study was to determine whether the anesthetic propofol alters brain uptake of (11)C-PBR28 in healthy subjects. METHODS Ten healthy subjects (5 men; 5 women) each underwent 2 dynamic brain PET scans on the same day, first at baseline and then with intravenous propofol anesthesia. The subjects were injected with 680 ± 14 MBq (mean ± SD) of (11)C-PBR28 for each PET scan. Brain uptake was measured as total distribution volume (V(T)) using the Logan plot and metabolite-corrected arterial input function. RESULTS Propofol decreased V(T), which corrects for any alteration of metabolism of the radioligand, by about 26% (P = 0.011). In line with the decrease in V(T), brain time-activity curves showed decreases of about 20% despite a 13% increase in plasma area under the curve with propofol. Reduction of V(T) with propofol was observed across all brain regions, with no significant region X condition interaction (P = 0.40). CONCLUSION Propofol anesthesia reduces the V(T) of (11)C-PBR28 by about 26% in the brains of healthy human subjects. Given this finding, future studies will measure neuroimmune activation in the brains of autistic volunteers and their age and sex-matched healthy controls using propofol anesthesia. We recommend that future PET studies using (11)C-PBR28 and concomitant propofol anesthesia, as would be required in impaired populations, include a control arm to account for the effects of propofol on brain measurements of TSPO.
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Affiliation(s)
- Christina S Hines
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, Maryland 20892-1026, USA
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Laymon CM, Narendran R, Mason NS, Carney JP, Lopresti BJ, Mathis CA, Mountz JM, Sashin D, Frankle WG. Human biodistribution and dosimetry of the PET radioligand [¹¹C]flumazenil (FMZ). Mol Imaging Biol 2012; 14:115-22. [PMID: 21365327 DOI: 10.1007/s11307-011-0478-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE We measure the whole-body distribution of IV injected [¹¹C]Flumazenil (FMZ) as a function of time in adult subjects and determine the absorbed radiation doses. PROCEDURES After injection with 770 MBq of [¹¹C]FMZ (nominal), each of six subjects underwent nine consecutive whole body PET scans. Twelve source organs were identified using PET attenuation and emission images. Activity within each organ as a function of time was determined from the sequence of the nine PET scans. Source organ time activity curves were integrated and normalized by the injected dose to yield source organ residence times for the no voiding situation. Separate bladder residence-time calculations were performed for the cases of a 1- and a 2-h voiding interval. Using the source organ residence times as input, the program OLINDA/EXM (Stabin et al. in J Nucl Med. 46:1023-1027, 2005) was used to perform dosimetry calculations for the various body organs and for the whole body. RESULTS For the no voiding situation, the average whole-body radiation equivalent dose was 3.02 × 10⁻³ mSv/MBq of injected [¹¹C]FMZ. The average effective dose and effective dose equivalent was 7.57 × 10⁻³ and 1.12 × 10⁻² mSv MBq⁻¹, respectively. The organ receiving the highest equivalent dose was the urinary bladder wall with an average of 6.32 × 10⁻² mSv MBq⁻¹. CONCLUSION On average, the administration of less than 790 MBq (21 mCi) of [¹¹C]FMZ yields (no voiding model) an organ equivalent dose of under 50 mSv [the single dose limit for research studies under US regulations (21CFR361.1) to body organs other than blood forming organs, gonads or the lens of the eye] to all organs. Equivalent dose to the blood forming organs and gonads from a 790 MBq administered FMZ dose is well under the 30 mSv limit provided under 21CFR361.1. Additionally, administration of less than 1320 MBq (35.7 mCi) yields an effective dose [International Commission on Radiation Protection (ICRP) 60 tissue weighting scheme] of under 10 mSv, which is the ICRP IIb (minor to intermediate) risk category limit.
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Affiliation(s)
- Charles M Laymon
- Department of Radiology, UPMC/Presbyterian Hospital, University of Pittsburgh, Room B-938, 200 Lothrop St., Pittsburgh, PA 15213, USA.
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Dhanani NM, Jiang Y. Anosmia and hypogeusia as a complication of general anesthesia. J Clin Anesth 2012; 24:231-3. [PMID: 22495083 DOI: 10.1016/j.jclinane.2011.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 08/15/2011] [Accepted: 08/27/2011] [Indexed: 10/28/2022]
Abstract
A 57 year old woman with no previous history of any sensory deficits developed anosmia and hypogeusia after general anesthesia for laparoscopic cholecystectomy, with complete recovery over 6 months. There were no other identifiable factors that may have contributed to her anosmia and hypogeusia after general anesthesia. As anosmia and hypogeusia related to anesthesia and surgery are not frequently reported, the incidence of these events related to anesthesia may be higher than expected.
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Affiliation(s)
- Nadya M Dhanani
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
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19
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Kim YJ, Lee H, Kim CH, Lee GY, Baik HJ, Han JI. Effect of flumazenil on recovery from anesthesia and the bispectral index after sevoflurane/fentanyl general anesthesia in unpremedicated patients. Korean J Anesthesiol 2012; 62:19-23. [PMID: 22323949 PMCID: PMC3272523 DOI: 10.4097/kjae.2012.62.1.19] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 06/13/2011] [Accepted: 06/14/2011] [Indexed: 12/02/2022] Open
Abstract
Background Benzodiazepines have a hypnotic/sedative effect through the inhibitory action of γ-aminobutyric acid type A receptor. Flumazenil antagonizes these effects via competitive inhibition, so it has been used to reverse the effect of benzodiazepines. Recently, flumazenil has been reported to expedite recovery from propofol/remifentanil and sevoflurane/remifentanil anesthesia without benzodiazepines. Endogenous benzodiazepine ligands (endozepines) were isolated in several tissues of individuals who had not received benzodiazepines. Methods Forty-five healthy unpremedicated patients were randomly allocated to either flumazenil or a control groups. Each patient received either a single dose of 0.3 mg of flumazenil (n = 24) or placebo (n = 21). After drug administration, various recovery parameters and bispectral index (BIS) values in the flumazenil and control groups were compared. Results Mean time to spontaneous respiration, eye opening on verbal command, hand squeezing on verbal command, extubation and time to date of birth recollection were significantly shorter in the flumazenil group than in the control group (P = 0.004, 0.007, 0.005, 0.042, and 0.016, respectively). The BIS value was significantly higher in flumazenil group than in the control group beginning 6 min after flumazenil administration. Conclusions Administration of a single dose of 0.3 mg of flumazenil to healthy, unpremedicated patients at the end of sevoflurane/fentanyl anesthesia without benzodiazepines resulted in earlier emergence from anesthesia and an increase in the BIS value. This may indicate that flumazenil could have an antagonistic effect on sevoflurane or an analeptic effect through endozepine-dependent mechanisms.
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Affiliation(s)
- Yi Jeong Kim
- Department of Anesthesiology and Pain Medicine, School of Medicine, Ewha Womans University, Seoul, Korea
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Kaskinoro K, Maksimow A, Långsjö J, Aantaa R, Jääskeläinen S, Kaisti K, Särkelä M, Scheinin H. Wide inter-individual variability of bispectral index and spectral entropy at loss of consciousness during increasing concentrations of dexmedetomidine, propofol, and sevoflurane. Br J Anaesth 2011; 107:573-80. [DOI: 10.1093/bja/aer196] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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21
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Nagashima Y, Suzuki T, Terada S, Tsuji S, Misawa K. In vivo molecular labeling of halogenated volatile anesthetics via intrinsic molecular vibrations using nonlinear Raman spectroscopy. J Chem Phys 2011; 134:024525. [PMID: 21241138 DOI: 10.1063/1.3526489] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Halogenated volatile anesthetics are frequently used for inhaled anesthesia in clinical practice. No appropriate biological method has been available for visualizing their localization in action. Therefore, despite their frequent use, the mechanism of action of these drugs has not been fully investigated. We measured coherent anti-Stokes Raman scattering (CARS) spectra of sevoflurane and isoflurane, two of the most representative volatile anesthetics, and determined the low-frequency vibrational modes without nonresonant background disturbance. Molecular dynamics calculations predict that these modes are associated with multiple halogen atoms. Because halogen atoms rarely appear in biological compounds, the entire spectral landscape of these modes is expected to be a good marker for investigating the spatial localization of these drugs within the intracellular environment. Using live squid giant axons, we could detect the unique CARS spectra of sevoflurane for the first time in a biological setting.
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Affiliation(s)
- Yu Nagashima
- Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588, Japan
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22
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Flumazenil expedites recovery from sevoflurane/remifentanil anaesthesia when administered to healthy unpremedicated patients. Eur J Anaesthesiol 2011; 27:955-9. [PMID: 20864893 DOI: 10.1097/eja.0b013e3283398ef9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND OBJECTIVE To investigate the hypothesis that 0.3 mg flumazenil administered to healthy unpremedicated patients at the end of deep surgical sevoflurane/remifentanil anaesthesia would expedite recovery. Flumazenil, an imidazobenzodiazepine derivative, antagonizes the hypnotic/sedative effects of benzodiazepines on γ-aminobutyric acid receptors. However, endogenous benzodiazepine ligands (endozepines) were isolated in mammalian tissues of individuals who had not received benzodiazepines. METHODS Twenty-four healthy unpremedicated patients, scheduled to undergo elective surgery requiring general anaesthesia, were randomly allocated to receive either a single dose of 0.3 mg flumazenil (n = 14) or placebo (n = 10) intravenously at the end of the surgical procedure just before the discontinuation of the volatile anaesthetic. After study drug administration, the authors compared various recovery parameters in the flumazenil and control groups. RESULTS Median time to spontaneous respiration, eye opening on verbal command, extubation and time to date of birth recollection was significantly shorter in the flumazenil group than in the control group [2.5 min (2.0-3.0) vs. 7.0 min (6.8-8.3), 3.4 min (3.0-4.0) vs. 8.1 min (6.9-10.2), 4.0 min (3.0-5.0) vs. 9.0 min (7.0-10.8) and 4.7 min (4.0-5.0) vs. 10.3 min (8.0-12.0), respectively]. CONCLUSION Administration of a single dose of 0.3 mg flumazenil to healthy unpremedicated patients at the end of sevoflurane/remifentanil anaesthesia results in earlier emergence from anaesthesia and significantly expedites recovery. This could redefine the role of flumazenil in general anaesthesia, implicating endozepine-dependent mechanisms.
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Konstantinidis I, Tsakiropoulou E, Iakovou I, Douvantzi A, Metaxas S. Anosmia after general anaesthesia: a case report. Anaesthesia 2009; 64:1367-70. [PMID: 19849684 DOI: 10.1111/j.1365-2044.2009.06071.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Although anaesthetic drugs are included among the aetiological factors of anosmia, limited reports exist of anosmia induced by general anaesthesia. We present the case of a 60-year-old female patient with a 3-month history of altered smell and taste immediately after recovery from general anaesthesia for a urological operation. The anaesthetic drugs used were fentanyl, propofol and sevoflurane. Clinical examination and a computed tomography brain scan did not reveal any pathology. Psychophysical testing showed anosmia and normal taste function. Imaging studies using single photon emission computed tomography of the brain were performed twice: as a baseline examination; and after odour stimulation with phenyl ethyl alcohol. Normal brain activity without reaction to odorous stimuli suggested peripheral dysfunction or stimuli transmission problems. The patient, after four months of olfactory retraining, demonstrated significant improvement. The onset of the dysfunction in relation with the imaging findings may imply that anaesthetics could induce the olfactory dysfunction.
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Affiliation(s)
- I Konstantinidis
- Academic Otorhinolaryngology Department, Papageorgiou Hospital, Thessaloniki, Greece
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24
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Atack JR, Maubach KA, Wafford KA, O'Connor D, Rodrigues AD, Evans DC, Tattersall FD, Chambers MS, MacLeod AM, Eng WS, Ryan C, Hostetler E, Sanabria SM, Gibson RE, Krause S, Burns HD, Hargreaves RJ, Agrawal NGB, McKernan RM, Murphy MG, Gingrich K, Dawson GR, Musson DG, Petty KJ. In Vitro and in Vivo Properties of 3-tert-Butyl-7-(5-methylisoxazol-3-yl)-2-(1-methyl-1H-1,2,4-triazol-5-ylmethoxy)-pyrazolo[1,5-d]-[1,2,4]triazine (MRK-016), a GABAA Receptor α5 Subtype-Selective Inverse Agonist. J Pharmacol Exp Ther 2009; 331:470-84. [DOI: 10.1124/jpet.109.157636] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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25
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Frankle WG, Cho RY, Narendran R, Mason NS, Vora S, Litschge M, Price JC, Lewis DA, Mathis CA. Tiagabine increases [11C]flumazenil binding in cortical brain regions in healthy control subjects. Neuropsychopharmacology 2009; 34:624-33. [PMID: 18615011 PMCID: PMC2754778 DOI: 10.1038/npp.2008.104] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Accumulating evidence indicates that synchronization of cortical neuronal activity at gamma-band frequencies is important for various types of perceptual and cognitive processes and that GABA-A receptor-mediated transmission is required for the induction of these network oscillations. In turn, the abnormalities in GABA transmission postulated to play a role in psychiatric conditions such as schizophrenia might contribute to the cognitive deficits seen in this illness. We measured the ability to increase GABA in eight healthy subjects by comparing the binding of [(11)C]flumazenil, a positron emission tomography (PET) radiotracer specific for the benzodiazepine (BDZ) site, at baseline and in the presence of an acute elevation in GABA levels through the blockade of the GABA membrane transporter (GAT1). Preclinical work suggests that increased GABA levels enhance the affinity of GABA-A receptors for BDZ ligands (termed 'GABA shift'). Theoretically, such an increase in the affinity of GABA-A receptors should be detected as an increase in the binding of a GABA-A BDZ-receptor site-specific PET radioligand. GAT1 blockade resulted in significant increases in mean (+/- SD) [(11)C]flumazenil-binding potential (BP(ND)) over baseline in brain regions representing the major functional domains of the cerebral cortex: association cortex +15.2+/-20.2% (p=0.05), sensory cortex +13.5+/-15.5% (p=0.03) and limbic (medial temporal lobe, MTL) +16.4+/-20.2% (p=0.03). The increase in [(11)C]flumazenil-BP(ND) was not accounted for by differences in the plasma-free fraction (f(P); paired t-test p=0.24) or changes in the nonspecific binding (pons V(T), p=0.73). Moreover, the ability to increase GABA strongly predicted (r=0.85, p=0.015) the ability to entrain cortical networks, measured through EEG gamma synchrony during a cognitive control task in these same subjects. Although additional studies are necessary to further validate this technique, these data provide preliminary evidence of the ability to measure in vivo, with PET, acute fluctuations in extracellular GABA levels and provide the first in vivo documentation of a relationship between GABA neurotransmission and EEG gamma-band power in humans.
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Affiliation(s)
- W Gordon Frankle
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA.
| | - Raymond Y Cho
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rajesh Narendran
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA,Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - N Scott Mason
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shivangi Vora
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Maralee Litschge
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Julie C Price
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - David A Lewis
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA,Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Chester A Mathis
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
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Qiu M, Ramani R, Swetye M, Rajeevan N, Constable RT. Anesthetic effects on regional CBF, BOLD, and the coupling between task-induced changes in CBF and BOLD: an fMRI study in normal human subjects. Magn Reson Med 2009; 60:987-96. [PMID: 18816821 DOI: 10.1002/mrm.21759] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Functional MR imaging was performed in sixteen healthy human subjects measuring both regional cerebral blood flow (CBF) and blood oxygen level dependent (BOLD) signal when visual and auditory stimuli were presented to subjects in the presence or absence of anesthesia. During anesthesia, 0.25 mean alveolar concentration (MAC) sevoflurane was administrated. We found that low-dose sevoflurane decreased the task-induced changes in both BOLD and CBF. Within the visual and auditory regions of interest inspected, both baseline CBF and the task-induced changes in CBF decreased significantly during anesthesia. Low-dose sevoflurane significantly altered the task-induced CBF-BOLD coupling; for a unit change of CBF, a larger change in BOLD was observed in the anesthesia condition than in the anesthesia-free condition. Low-dose sevoflurane was also found to have significant impact on the spatial nonuniformity of the task-induced coupling. The alteration of task-induced CBF-BOLD coupling by low-dose sevoflurane introduces ambiguity to the direct interpretation of functional MRI (fMRI) data based on only one of the indirect measures-CBF or BOLD. Our observations also indicate that the manipulation of the brain with an anesthetic agent complicates the model-based quantitative interpretation of fMRI data, in which the relative task-induced changes in oxidative metabolism are calculated by means of a calibrated model given the relative changes in the indirect vascular measures, usually CBF and BOLD.
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Affiliation(s)
- Maolin Qiu
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520-2048, USA.
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27
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Salmi E, Aalto S, Hirvonen J, Långsjö JW, Maksimow AT, Oikonen V, Metsähonkala L, Virkkala J, Någren K, Scheinin H. Measurement of GABAA receptor binding in vivo with [11C]Flumazenil: A test–retest study in healthy subjects. Neuroimage 2008; 41:260-9. [DOI: 10.1016/j.neuroimage.2008.02.035] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 02/24/2008] [Accepted: 02/26/2008] [Indexed: 11/25/2022] Open
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Xenon Does Not Affect γ-Aminobutyric Acid Type A Receptor Binding in Humans. Anesth Analg 2008; 106:129-34, table of contents. [DOI: 10.1213/01.ane.0000287658.14763.13] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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29
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Atack JR, Scott-Stevens P, Beech JS, Fryer TD, Hughes JL, Cleij MC, Baron JC, Clark JC, Hargreaves RJ, Aigbirhio FI. Comparison of lorazepam [7-chloro-5-(2-chlorophenyl)-1,3-dihydro-3-hydroxy-2H-1,4-benzodiazepin-2-one] occupancy of rat brain gamma-aminobutyric acid(A) receptors measured using in vivo [3H]flumazenil (8-fluoro 5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylic acid ethyl ester) binding and [11C]flumazenil micro-positron emission tomography. J Pharmacol Exp Ther 2006; 320:1030-7. [PMID: 17164474 DOI: 10.1124/jpet.106.114884] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The occupancy by lorazepam of the benzodiazepine binding site of rat brain GABA(A) receptors was compared when measured using either in vivo binding of [(3)H]flumazenil (8-fluoro 5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine-3-carboxylic acid ethyl ester) in terminal studies or [(11)C]flumazenil binding in anesthetized animals assessed using a small animal positron emission tomography (PET) scanner (micro-PET). In addition, as a bridging study, lorazepam occupancy was measured using [(3)H]flumazenil in vivo binding in rats anesthetized and dosed under micro-PET conditions. Plasma lorazepam concentrations were also determined, and for each occupancy method, the concentration required to produce 50% occupancy (EC(50)) was calculated because this parameter is independent of the route of lorazepam administration. For the in vivo binding assay, lorazepam was dosed orally (0.1-10 mg/kg), whereas for the micro-PET study, lorazepam was given via the i.v. route as a low dose (0.75 mg/kg bolus) and then a high dose (0.5 mg/kg bolus then 0.2 mg/ml infusion). The lorazepam plasma EC(50) in the [(11)C]flumazenil micro-PET study was 96 ng/ml [95% confidence intervals (CIs) = 74-124 ng/ml], which was very similar to the [(3)H]flumazenil micro-PET simulation study (94 ng/ml; 95% CI = 63-139 ng/ml), which in turn was comparable with the [(3)H]flumazenil in vivo binding study (134 ng/ml; 95% CI = 119-151 ng/ml). These data clearly show that despite the differences in dosing (i.v. in anesthetized versus orally in conscious rats) and detection (in vivo dynamic PET images versus ex vivo measurements in filtered and washed brain homogenates), [(11)C]flumazenil micro-PET produces results similar to [(3)H]flumazenil in vivo binding.
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Affiliation(s)
- John R Atack
- Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, United Kingdom.
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Lysakowski C, Dumont L, Czarnetzki C, Bertrand D, Tassonyi E, Tramèr MR. The effect of cigarette smoking on the hypnotic efficacy of propofol. Anaesthesia 2006; 61:826-31. [PMID: 16922747 DOI: 10.1111/j.1365-2044.2006.04747.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The bispectral index (BIS) was used to examine the hypnotic efficacy of propofol in 25 smokers (20 cigarettes/day for 2 years) and 24 matched non-smokers (same gender, age, height, weight). BIS was recorded at baseline, at four incremental effect-site concentrations of propofol and at loss of consciousness. Compared with non-smokers, smokers were found to have higher BIS values at baseline (mean (SD)) (97 (1) vs 98 (1)), at 0.7 microg x ml(-1) (95 (3) vs 97 (1)) and at 1.1 microg x ml(-1) (89 (6) vs 94 (4)), p = 0.0099, and they lost consciousness at higher propofol concentrations (2.0 (0.4) vs 2.4 (0.8) microg x ml(-1)), p = 0.03, and at lower BIS values (66 (10) vs 60 (10)), p = 0.04. The hypnotic efficacy of propofol is reduced when used at low effect-site concentrations in smokers. This phenomenon may have some impact on the management of smokers undergoing sedation using target controlled infusion systems.
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Affiliation(s)
- C Lysakowski
- Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology and Intensive Care, Geneva University Hospitals, Geneva, Switzerland.
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Sakiyama Y, Saito M, Inoue O. Acute treatment with pentobarbital alters the kinetics of in vivo receptor binding in the mouse brain. Nucl Med Biol 2006; 33:535-41. [PMID: 16720246 DOI: 10.1016/j.nucmedbio.2006.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 02/03/2006] [Accepted: 02/08/2006] [Indexed: 11/15/2022]
Abstract
The effect of pentobarbital, a sedative-hypnotic barbiturate, on the in vivo binding of benzodiazepine receptors in the mouse brain was investigated. Dose-related changes in the apparent binding of [3H]Ro15-1788 ([3H]flumazenil) in the cerebral cortex, cerebellum and pons-medulla were observed by pretreatment with pentobarbital. For quantification of the kinetic properties of the in vivo binding of [3H]Ro15-1788, time courses of radioactivity following its injection were examined, and kinetic analysis was performed using the compartment model. The time courses of radioactivity following injection of [3H]Ro15-1788 with 3 mg/kg Ro15-1788 were used as input function. In all regions studied, rate constants between input compartment and specific binding compartment were significantly decreased by pentobarbital. However, no significant alterations in the binding potential (BP=K3/K4) of benzodiazepine receptors by pentobarbital were observed in any of the regions. A saturation experiment indicated that the decrease in the input rate constant (K3), which includes both the association rate constant (k(on)) and the number of binding sites available (B(max)), was mainly due to decrease in k(on). These results suggest that apparent increases in binding at 20 min after tracer injection were due to the decrease in the association and dissociation rates of binding in vivo.
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Affiliation(s)
- Yojiro Sakiyama
- Division of Clinical Research, National Institute of Radiological Sciences, Inage-ku, Chibashi 263-8555, Japan.
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Kung MP, Kung HF. Mass effect of injected dose in small rodent imaging by SPECT and PET. Nucl Med Biol 2006; 32:673-8. [PMID: 16243641 DOI: 10.1016/j.nucmedbio.2005.04.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Revised: 04/02/2005] [Accepted: 04/02/2005] [Indexed: 10/25/2022]
Abstract
This paper discusses the effect of mass (chemical quantity) of injected dose on positron emission tomography (PET) and single-photon emission computed tomography (SPECT). Commonly, PET or SPECT imaging study uses a "no-carrier added" dose, which contains a small amount of radioactive imaging agent (in picogram to microgram). For small animal (rodent) imaging studies, specifically targeting binding sites or biological processes, the mass (chemical quantity) in the dose may significantly modify the binding, pharmacokinetics and, ultimately, the imaging outcome. Due to differences in size and other physiological factors between humans and rodents, there is a dramatic divergence of mass effect between small animal and human imaging study. In small animal imaging studies, the mass, or effective dose (ED(50)), a dose required for 50% of receptor or binding site occupancy, is usually not directly related to binding potential (B(max)/K(d)) (measured by in vitro binding assay). It is likely that dynamic interplays between specific and nonspecific binding in blood circulation, transient lung retention, kidney excretion, liver-gallbladder flow, soft tissue retention as well as metabolism could each play a significant role in determining the concentration of the tracer in the target regions. When using small animal imaging for studying drug occupancy (either by a pretreatment, coinjection or chasing dose), the mass effects on imaging outcome are important factors for consideration.
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Affiliation(s)
- Mei-Ping Kung
- Department of Radiology, University of Pennsylvania, Philadelphia, 19104, USA
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Salmi E, Långsjö JW, Aalto S, Någren K, Metsähonkala L, Kaisti KK, Korpi ER, Hietala J, Scheinin H. Subanesthetic ketamine does not affect 11C-flumazenil binding in humans. Anesth Analg 2005; 101:722-725. [PMID: 16115981 DOI: 10.1213/01.ane.0000156951.83242.8d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Positron emission tomography (PET) studies suggest that propofol and inhaled anesthetics increase (11)C-flumazenil binding in the living human brain, thus supporting the involvement of gamma-aminobutyric acid type A (GABA(A)) receptors in the mechanism of action of these drugs. Ketamine produces its anesthetic effects primarily by N-methyl-d-aspartate receptor antagonism, but it may also have GABA(A) receptor agonistic properties. By using PET, we studied the cerebral (11)C-flumazenil binding in 10 healthy subjects before and during a subanesthetic racemic ketamine infusion reaching a serum concentration of 350 +/- 42 ng/mL. Ketamine did not affect (11)C-flumazenil binding to GABA(A) receptor in the brain, indicating that this mechanism is of minor importance in the actions of subanesthetic ketamine.
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Affiliation(s)
- Elina Salmi
- Turku PET Centre, Centre for Cognitive Neuroscience, and the Department of Pharmacology and Clinical Pharmacology, University of Turku, and the Departments of Anesthesiology and Intensive Care, Child Neurology, and Psychiatry, Turku University Hospital, Turku, Finland; Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland
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Alkire MT, Miller J. General anesthesia and the neural correlates of consciousness. PROGRESS IN BRAIN RESEARCH 2005; 150:229-44. [PMID: 16186027 DOI: 10.1016/s0079-6123(05)50017-7] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The neural correlates of consciousness must be identified, but how? Anesthetics can be used as tools to dissect the nervous system. Anesthetics not only allow for the experimental investigation into the conscious-unconscious state transition, but they can also be titrated to subanesthetic doses in order to affect selected components of consciousness such as memory, attention, pain processing, or emotion. A number of basic neuroimaging examinations of various anesthetic agents have now been completed. A common pattern of regional activity suppression is emerging for which the thalamus is identified as a key target of anesthetic effects on consciousness. It has been proposed that a neuronal hyperpolarization block at the level of the thalamus, or thalamocortical and corticocortical reverberant loops, could contribute to anesthetic-induced unconsciousness. However, all anesthetics do not suppress global cerebral metabolism and cause a regionally specific effect on thalamic activity. Ketamine, a so-called dissociative anesthetic agent, increases global cerebral metabolism in humans at doses associated with a loss of consciousness. Nevertheless, it is proposed that those few anesthetics not associated with a global metabolic suppression effect might still have their effects on consciousness mediated at the level of thalamocortical interactions, if such agents scramble the signals associated with normal neuronal network reverberant activity. Functional and effective connectivity are analysis techniques that can be used with neuroimaging to investigate the signal scrambling effects of various anesthetics on network interactions. Whereas network interactions have yet to be investigated with ketamine, a thalamocortical and corticocortical disconnection effect during unconsciousness has been found for both suppressive anesthetic agents and for patients who are in the persistent vegetative state. Furthermore, recovery from a vegetative state is associated with a reconnection of functional connectivity. Taken together these intriguing observations offer strong empirical support that the thalamus and thalamocortical reverberant network loop interactions are at the heart of the neurobiology of consciousness.
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Affiliation(s)
- Michael T Alkire
- Department of Anesthesiology and The Center for the Neurobiology of Learning and Memory, University of California at Irvine, Irvine, CA, USA.
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