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Baglini E, Poggetti V, Cavallini C, Petroni D, Forini F, Nicolini G, Barresi E, Salerno S, Costa B, Iozzo P, Neglia D, Menichetti L, Taliani S, Da Settimo F. Targeting the Translocator Protein (18 kDa) in Cardiac Diseases: State of the Art and Future Opportunities. J Med Chem 2024; 67:17-37. [PMID: 38113353 PMCID: PMC10911791 DOI: 10.1021/acs.jmedchem.3c01716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/16/2023] [Accepted: 11/24/2023] [Indexed: 12/21/2023]
Abstract
Mitochondria dysfunctions are typical hallmarks of cardiac disorders (CDs). The multiple tasks of this energy-producing organelle are well documented, but its pathophysiologic involvement in several manifestations of heart diseases, such as altered electromechanical coupling, excitability, and arrhythmias, is still under investigation. The human 18 kDa translocator protein (TSPO) is a protein located on the outer mitochondrial membrane whose expression is altered in different pathological conditions, including CDs, making it an attractive therapeutic and diagnostic target. Currently, only a few TSPO ligands are employed in CDs and cardiac imaging. In this Perspective, we report an overview of the emerging role of TSPO at the heart level, focusing on the recent literature concerning the development of TSPO ligands used for fighting and imaging heart-related disease conditions. Accordingly, targeting TSPO might represent a successful strategy to achieve novel therapeutic and diagnostic strategies to unravel the fundamental mechanisms and to provide solutions to still unanswered questions in CDs.
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Affiliation(s)
- Emma Baglini
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Valeria Poggetti
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
| | - Chiara Cavallini
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Debora Petroni
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Francesca Forini
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Giuseppina Nicolini
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Elisabetta Barresi
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
| | - Silvia Salerno
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
| | - Barbara Costa
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
| | - Patricia Iozzo
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Danilo Neglia
- Fondazione
CNR/Regione Toscana Gabriele Monasterio, Cardiovascular and Imaging
Departments, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Luca Menichetti
- Institute
of Clinical Physiology, National Research Council of Italy, CNR Research Area, Via G. Moruzzi 1, Pisa 56124, Italy
| | - Sabrina Taliani
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
| | - Federico Da Settimo
- Department
of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy
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Translocator protein (18 kDa): a promising therapeutic target and diagnostic tool for cardiovascular diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:162934. [PMID: 23251719 PMCID: PMC3516045 DOI: 10.1155/2012/162934] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 10/22/2012] [Accepted: 11/04/2012] [Indexed: 01/15/2023]
Abstract
The translocator protein (18 kDa) (TSPO) is a five transmembrane domain protein in mitochondria, abundantly expressed in a variety of organs and tissues. TSPO contributes to a wide range of biological processes, including cholesterol transportation, mitochondrial membrane potential and respiratory chain regulation, apoptosis, and oxidative stress. Recent studies have demonstrated that TSPO might also be involved in the physiological regulation of cardiac chronotropy and inotropy. Accordingly, TSPO ligands play significant roles in protecting the cardiovascular systems under pathological conditions through cardiac electrical activity retention, intracellular calcium maintenance, mitochondrial energy provision, mitochondrial membrane potential equilibrium, and reactive oxygen species inhibition. This paper focuses on the physiological and pathological characteristics of TSPO in the cardiovascular systems and also summarizes the properties of TSPO ligands. TSPO represents a potential therapeutic target and diagnostic tool for cardiovascular diseases including arrhythmia, myocardial infarction, cardiac hypertrophy, atherosclerosis, myocarditis, and large vessel vasculitis.
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Surinkaew S, Chattipakorn S, Chattipakorn N. Roles of mitochondrial benzodiazepine receptor in the heart. Can J Cardiol 2011; 27:262.e3 -13. [PMID: 21459278 DOI: 10.1016/j.cjca.2010.12.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Accepted: 06/02/2010] [Indexed: 12/01/2022] Open
Abstract
Mitochondrial benzodiazepine receptor (mBzR) is a type of peripheral benzodiazepine receptor that is located in the outer membrane of mitochondria. It is an 18-kDa protein that can form a multimeric complex with voltage-dependent anion channel (32 kDa) and adenine nucleotide translocator (30 kDa). mBzR is found in various species and abundantly distributed in peripheral tissues, including the cardiovascular system. The mitochondria are well known as the site of energy production, and the heart is the organ that highly requires this energy supply. In the past decades, it has been shown that mBzR plays a critical role in regulating mitochondrial and heart functions. A growing body of evidence demonstrates that mBzR is associated with regulation of mitochondrial respiration, mitochondrial membrane potential, apoptosis, and reactive oxygen species production. Moreover, mBzR has been suggested to play a role in alteration of physiological effects in the heart such as contractility and heart rate. mBzR is involved in the pathologic condition such as ischemia/reperfusion injury, responses to stress, and changes in electrophysiological properties and arrhythmogenesis. In this review, evidence of the roles of mBzR in the heart under both physiological and pathologic conditions is presented. Clinical studies regarding the use of pharmacologic intervention involving mBzR in the heart are also discussed as a possible target for the treatment of electrical and mechanical dysfunction in the heart.
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Affiliation(s)
- Sirirat Surinkaew
- Department of Physiology, Chiang Mai University, Chiang Mai, Thailand
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Brown DA, Aon MA, Akar FG, Liu T, Sorarrain N, O'Rourke B. Effects of 4'-chlorodiazepam on cellular excitation-contraction coupling and ischaemia-reperfusion injury in rabbit heart. Cardiovasc Res 2008; 79:141-9. [PMID: 18304929 DOI: 10.1093/cvr/cvn053] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
AIMS Recent evidence indicates that the activity of energy-dissipating ion channels in the mitochondria can influence the susceptibility of the heart to ischaemia-reperfusion injury. In this study, we describe the effects of 4'-chlorodiazepam (4-ClDzp), a well-known ligand of the mitochondrial benzodiazepine receptor, on the physiology of both isolated cardiomyocytes and intact hearts. METHODS AND RESULTS We used current- and voltage-clamp methods to determine the effects of 4-ClDzp on excitation-contraction coupling in isolated rabbit heart cells. At the level of the whole heart, we subjected rabbit hearts to ischaemia/reperfusion in order to determine how 4-ClDzp influenced the susceptibility to arrhythmias and contractile dysfunction. In isolated rabbit cardiomyocytes, 4-ClDzp evoked a significant reduction in the cardiac action potential that was associated with a decrease in calcium currents and peak intracellular calcium transients. In intact perfused normoxic rabbit hearts, 4-ClDzp mediated a dose-dependent negative inotropic response, consistent with the observation that 4-ClDzp was reducing calcium influx. Hearts that underwent 30 min of global ischaemia and 30 min of reperfusion were protected against reperfusion arrhythmias and post-ischaemic contractile impairment when 4-ClDzp (24 microM) was administered throughout the protocol or as a single bolus dose given at the onset of reperfusion. In contrast, hearts treated with cyclosporin-A, a classical blocker of the mitochondrial permeability transition pore, were not protected against reperfusion arrhythmias. CONCLUSION The findings indicate that the effects of 4-ClDzp on both mitochondrial and sarcolemmal ion channels contribute to protection against post-ischaemic cardiac dysfunction. Of clinical relevance, the compound is effective when given upon reperfusion, unlike other pre-conditioning agents.
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Affiliation(s)
- David A Brown
- Department of Medicine, Division of Cardiology, Institute of Molecular Cardiobiology, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, 1059 Ross Building, Baltimore, MD 21205, USA
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Klockgether-Radke AP, Pawlowski P, Neumann P, Hellige G. Mechanisms involved in the relaxing effect of midazolam on coronary arteries. Eur J Anaesthesiol 2005; 22:135-9. [PMID: 15816593 DOI: 10.1017/s0265021505000256] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE Hypotension, especially in elderly and hypovolaemic patients, is frequently associated with intravenous midazolam administration. The mechanisms are not completely understood. This study was designed to investigate the mechanisms involved in the relaxing effect of midazolam on coronary arteries. METHODS The substance was studied in isolated porcine coronary artery rings precontracted by either potassium chloride or prostaglandin F2alpha. RESULTS Midazolam caused vasodilatation in a concentration-dependent manner. Relaxation was more pronounced in prostaglandin F2alpha precontracted segments than in those treated with potassium chloride (P < 0.001). Vasodilatation was unaffected by Nomega-nitro-L-arginine, indomethacin and glibenclamide. Tetraethylammonium chloride, an inhibitor of the BK(Ca) K+ channel (a high conductance Ca(2+)-sensitive K+ channel), dose dependently attenuated the vasodilating effect of midazolam (P < 0.01). CONCLUSIONS Hyperpolarization of the smooth muscle cell in the vessel wall, elicited by the activation the BK(Ca) K+ channel, may contribute to the vasorelaxing effect of midazolam.
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Affiliation(s)
- A P Klockgether-Radke
- Georg-August University of Göttingen, Centre of Anaesthesiology, Emergency and Intensive Care Medicine, Department of Anaesthesiological Research, Göttingen, Germany.
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Goel S, Bhardwaj N, Grover VK. Intrathecal fentanyl added to intrathecal bupivacaine for day case surgery: a randomized study. Eur J Anaesthesiol 2003; 20:294-7. [PMID: 12703834 DOI: 10.1017/s0265021503000462] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE The implication of intrathecal lidocaine in neurological toxicity has made intrathecal bupivacaine the commonly used drug for local anaesthesia in ambulatory surgery. However, in high doses intrathecal bupivacaine may produce a high level of sensory and motor block, and arterial hypotension; discharge from hospital may be delayed. Intrathecal opioids added to low-dose local anaesthetics produce a synergistic effect without increasing the sympathetic block or delaying discharge. The aim of our study was to identify the minimum effective dose of intrathecal fentanyl that in combination with low-dose intrathecal bupivacaine would provide adequate surgical conditions without prolonging recovery. METHODS A prospective, single, blind, randomized study was conducted in 45 adult males scheduled for minor urological procedures using intrathecal anaesthesia on a day care basis. Patients were randomly assigned to one of three groups (n = 15 each). They received bupivacaine 0.17% 5 mg--with either fentanyl 7.5 microg (fenta-7.5), 10 microg (fenta-10) or 12.5 microg (fenta-12.5) intrathecally in a total volume of 3 mL. The quality of anaesthesia, haemodynamic stability, time to two-segment and S2 regression, time to micturition, and time to discharge were assessed. RESULTS The time to two-segment regression and S2 regression with fenta-12.5 was significantly longer than with fenta-7.5 and fenta-10 (P < 0.01). Fenta-7.5 had a significantly higher number of failed blocks (four patients) compared with fenta-12.5 (P < 0.05). The time out of bed, time to micturition and time to discharge were significantly longer with fenta-10 and fenta-12.5 compared with fenta-7.5, and also with fenta-12.5 compared with fenta-10 (P < 0.01). Haemodynamic stability did not differ for all the drug combinations. CONCLUSIONS Fentanyl 12.5 microg added to low-dose bupivacaine (5 mg) intrathecally provides better surgical anaesthesia and increased reliability of block than intrathecal fentanyl 7.5 or 10 microg. Haemodynamic stability was the same for all dose combinations used.
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Affiliation(s)
- S Goel
- Postgraduate Institute of Medical Education and Research, Department of Anaesthesia and Intensive Care, Chandigarh, India
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Abstract
The aim of this Review is to introduce anaesthesiologists to the basic physical principles that are important for their work. A better understanding of the underlying processes during anaesthesia is required for greater safety and efficiency. Relevant physical quantities are presented along with the area of anaesthesiology where they are used. This approach provides better targeting to the needs of practising anaesthesiologists. This text has been a part of a specialist course in anaesthesiology at the University of Ljubljana for some years. Current results show that both the students and the specialist anaesthesiologists now show a better understanding of the underlying physical principles required for their work and are more successful in fulfilling the needs of their practical work.
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Affiliation(s)
- A Manohin
- Medical Center, Department for Anaesthesiology, Ljubljana, Slovenia.
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8
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High-dose midazolam and the attenuation of the contractile response to vasoconstrictors in coronary artery segments. Eur J Anaesthesiol 2003. [DOI: 10.1097/00003643-200304000-00003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Klockgether-Radke AP, Thudium A, Frerichs A, Kettler D, Hellige G. High-dose midazolam and the attenuation of the contractile response to vasoconstrictors in coronary artery segments. Eur J Anaesthesiol 2003; 20:289-93. [PMID: 12703833 DOI: 10.1017/s0265021503000450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND AND OBJECTIVE Benzodiazepines may cause hypotension and are reported to interfere with smooth vascular muscle activity. The aim was to elucidate the influence of three different benzodiazepines on the vascular reactivity of coronary arteries. METHODS Using the model of isolated vessels, we studied the impact of midazolam (0.15, 1.5, 15 microg mL(-1)), diazepam (0.1, 1.0, 10 microg mL(-1)) and flunitrazepam (0.01, 0.1, 1.0 microg mL(-1)) on the contractile responses to histamine (2 x 10(-5) mol L(-1)) and serotonin (3 x 10(-5) mol L(-1)) in isolated intact and denuded coronary arteries. RESULTS Midazolam significantly attenuated the contractile response when administered in high concentrations (15 microg mL(-1)). This effect was more pronounced in intact than in denuded preparations (histamine: -22.7 versus -7.3%, P = 0.0079; serotonin: -47.1 versus -15.9%, P < 0.0001). Diazepam and flunitrazepam exerted no significant effects on the vascular tone of coronary arteries. CONCLUSIONS Midazolam, but not diazepam or flunitrazepam, attenuates the contractile responses to vasoconstrictors in concentrations beyond those used in clinical practice. This effect is in part mediated by endothelial factors.
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Affiliation(s)
- A P Klockgether-Radke
- Georg-August University of Göttingen, Department of Anaesthesiological Research, Centre of Anaesthesiology, Emergency and Intensive Care Medicine, Göttingen, Germany.
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Payne K, Moore EW, Elliott RA, Pollard BJ, McHugh GA. Anaesthesia for day case surgery: a survey of adult clinical practice in the UK. Eur J Anaesthesiol 2003; 20:311-24. [PMID: 12703837 DOI: 10.1017/s0265021503000498] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND AND OBJECTIVE In October 2000, we conducted a national postal survey of consultant day case anaesthetists in the UK to explore the range and variation in the practice of anaesthetizing a patient for day case surgery (paediatrics, urology and orthopaedics). The survey was carried out as part of a larger study that comprised a major two-centre randomized controlled trial designed to investigate the costs and outcome of several anaesthetic techniques during day care surgery in paediatric and adult patients (cost-effectiveness study of anaesthesia in day case surgery). We report the findings of this national survey of adult urology and orthopaedic day case anaesthetic practice in the UK. METHODS The survey used a structured postal questionnaire and collected data on the duration of the surgical procedure; the use of premedication; the anaesthetic agents used for induction and maintenance; the fresh gas flows used for anaesthesia; the use of antiemetics; and the administration of local anaesthesia and analgesia. RESULTS The overall response rate for the survey was 74% (63% for urology, 67% for orthopaedics). The survey indicated the following practice in adult urology and adult orthopaedic day case surgery: 6 and 12% used premedication; propofol was the preferred induction agent (96 and 97%) and isoflurane the preferred maintenance agent (56 and 58%); 32 and 41% used prophylactic antiemetics; 86 and 93% used a laryngeal mask. CONCLUSIONS This survey identifies the variation in current clinical practice in adult day surgery anaesthesia in the UK and discusses this variation in the context of current published evidence.
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Affiliation(s)
- K Payne
- University of Manchester, School of Pharmacy & Pharmaceutical Sciences, Manchester, UK.
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Dahn J, Waschke KF, Stuck BA, Hörmann K. Fluid shifts in anaphylaxis. Eur J Anaesthesiol 2003; 20:331. [PMID: 12703839 DOI: 10.1017/s0265021503210516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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12
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White S, Parry M, Henderson K. Anaesthesia for total hip replacement in a patient with Holt-Oram syndrome. Eur J Anaesthesiol 2003; 20:336-8. [PMID: 12703842 DOI: 10.1017/s0265021503240515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fattorutto M, Pradier O, Jansens JL, Ickx B, Barvais L. Plateletpheresis the day before cardiac surgery and the impairment of platelet function. Eur J Anaesthesiol 2003; 20:338-40. [PMID: 12703843 DOI: 10.1017/s0265021503250511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Estebe JP, Le Corre P, Clément R, Du Plessis L, Chevanne F, Le Verge R, Ecoffey C. Effect of dexamethasone on motor brachial plexus block with bupivacaine and with bupivacaine-loaded microspheres in a sheep model. Eur J Anaesthesiol 2003; 20:305-10. [PMID: 12703836 DOI: 10.1017/s0265021503000486] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND AND OBJECTIVE It has been suggested that dexamethasone potentiates the sensory block produced by bupivacaine when both drugs are loaded in microspheres. The aim of the study was to evaluate the effect of dexamethasone on the brachial plexus block obtained with plain bupivacaine and bupivacaine-loaded microspheres. METHODS Dexamethasone alone (Group 5) or added to plain bupivacaine (75 mg) with (Groups 3 and 4) and without pH correction (Group 2) was compared with plain bupivacaine (75 mg; Group 1). The effect of a small dose of dexamethasone (0.42 mg) was then evaluated on the brachial plexus block obtained with bupivacaine (750 mg) as bupivacaine-loaded microspheres (Group 6). Dexamethasone was added either in the suspending medium (Group 7) or incorporated with bupivacaine into microspheres (Group 8). The motor block was evaluated in a plexus brachial sheep model. RESULTS Dexamethasone alone did not produce any motor block. When added to plain bupivacaine without pH correction, complete motor block could not be obtained. When the pH was corrected, addition of dexamethasone to plain bupivacaine seemed to delay the onset of motor block and did not prolong its duration, and it had no effect on the pharmacokinetics of bupivacaine. With bupivacaine-loaded microspheres, the duration of complete motor block was reduced when a small dose of dexamethasone was added in the suspending medium. However, the duration of motor block was significantly prolonged when dexamethasone was incorporated with bupivacaine into microspheres. CONCLUSIONS Despite the delayed onset of motor block, the incorporation of dexamethasone in bupivacaine-loaded microspheres dramatically increases the duration of action (700 +/- 485-5160 +/- 2136 min), which could be clinically relevant when such a drug-delivery system will be available.
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Affiliation(s)
- J P Estebe
- Université de Rennes 1, Service d'Anesthésie-Réanimation Chirurgicale 2, Hôpital Hôtel Dieu, Rennes, France.
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Kaya M, Sariyildiz O, Karakus D, Ozalp G, Kadiogullari DN. Tramadol versus meperidine in the treatment of shivering during spinal anaesthesia. Eur J Anaesthesiol 2003; 20:332-3. [PMID: 12703840 DOI: 10.1017/s0265021503220512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Linton NWF, Linton RAF. Haemodynamic response to a small intravenous bolus injection of epinephrine in cardiac surgical patients. Eur J Anaesthesiol 2003; 20:298-304. [PMID: 12703835 DOI: 10.1017/s0265021503000474] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE The aim was to study the rapid changes in cardiac output and systemic vascular resistance produced by intravenous epinephrine (5 microg) on a beat-by-beat basis. METHODS Ten patients were studied during cardiac surgery. Radial or brachial arterial pressure was recorded continuously during intravenous administration of epinephrine (5 microg). Cardiac output and systemic vascular resistance were derived for each beat using arterial pulse contour analysis calibrated by lithium indicator dilution. In each patient a further dose of epinephrine (5 microg) was administered during cardiopulmonary bypass with the blood flow kept constant so that changes in arterial pressure corresponded to changes in systemic vascular resistance. RESULTS When the patients were not on cardiopulmonary bypass, the epinephrine produced an initial increase in systemic vascular resistance to 129 +/- 15% (mean +/- SD) of control, followed by a more prolonged reduction to 57 +/- 13% of control. Cardiac output showed a small initial reduction coincident with the increase in systemic vascular resistance, followed by an increase to 152 +/- 24% of control. During cardiopulmonary bypass, the changes produced by epinephrine on systemic vascular resistance were qualitatively similar but smaller in amplitude, probably because of a greater volume of dilution in the bypass circuit. CONCLUSIONS Small bolus doses of epinephrine produce an initial increase in systemic vascular resistance followed by a much greater reduction that may cause hypotension.
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Affiliation(s)
- N W F Linton
- The Rayne Institute, St Thomas' Hospital, London, UK.
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Payne K, Moore EW, Elliott RA, Moore JK, McHugh GA. Anaesthesia for day case surgery: a survey of paediatric clinical practice in the UK. Eur J Anaesthesiol 2003; 20:325-30. [PMID: 12703838 DOI: 10.1017/s0265021503000504] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND AND OBJECTIVE In October 2000, we conducted a national postal survey of day case consultant anaesthetists in the UK to explore the range and variation in practice of anaesthetizing a patient for day case surgery (paediatrics, urology and orthopaedics). This paper reports the findings of this national survey of paediatric day case anaesthetic practice carried out as part of a major two-centre randomized controlled trial designed to investigate the costs and outcome of several anaesthetic techniques during day care surgery in paediatric and adult patients (cost-effectiveness study of anaesthesia in day case surgery). METHODS The survey used a structured postal questionnaire and collected data on the duration of surgical procedure; the use of premedication; the anaesthetic agents used for induction and maintenance; the fresh gas flow rates used for general anaesthesia; the use of antiemetics; and the administration of local anaesthesia and analgesia. RESULTS The overall response rate for the survey was 74 and 63% for the paediatric section of the survey. Respondents indicated that 19% used premedication, 63% used propofol for induction, 54% used isoflurane for maintenance, 24% used prophylactic antiemetics and 85%, used a laryngeal mask. The findings of this national survey are discussed and compared with published evidence. CONCLUSIONS This survey identifies the variation in clinical practice in paediatric day surgery anaesthesia in the UK.
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Affiliation(s)
- K Payne
- University of Manchester, School of Pharmacy & Pharmaceutical Sciences, Manchester, UK.
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Weber TP, Van Aken H, Kehrel BE, Meissner A, Brüssel T, Bullmann V, Winkelmann W, Heindel W, Rolf N. Epidural bleed and quadriplegia due to acquired platelet dysfunction unrelated to multiple spinal and epidural puncture. Eur J Anaesthesiol 2003; 20:333-6. [PMID: 12703841 DOI: 10.1017/s0265021503230519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Hellwagner K, Holzer A, Gustorff B, Schroegendorfer K, Greher M, Weindlmayr-Goettel M, Saletu B, Lackner FX. Recollection of dreams after short general anaesthesia: influence on patient anxiety and satisfaction. Eur J Anaesthesiol 2003; 20:282-8. [PMID: 12703832 DOI: 10.1017/s0265021503000449] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND AND OBJECTIVE We ascertained whether dreams during short general anaesthesia influence subsequent patient satisfaction and anxiety. METHODS Fifty female patients were randomized into two groups to test for a difference between intravenous and inhalational anaesthesias. In Group Propo, anaesthesia was induced and maintained with propofol; in Group Metho-Iso, anaesthesia was induced with methohexital and maintained with isoflurane. Satisfaction and anxiety with anaesthesia were evaluated using a visual analogue scale from 0 to 100. Dream incidence rate, satisfaction and anxiety were assessed from immediately after waking until 3 months later. RESULTS Seventeen patients (34%) dreamed during anaesthesia. There were no significant differences in satisfaction or anxiety after anaesthesia between the dreaming and non-dreaming patients (satisfaction, 92.3 +/- 21.6 versus 92.1 +/- 21.6; anxiety, 21.1 +/- 21.1 versus 30.3 +/- 32.1), or between Group Propo and Group Metho-Iso (satisfaction, 94.4 +/- 19.3 versus 90.0 +/- 23.4; anxiety, 26.0 +/- 27.6 versus 28.4 +/- 30.7). There was no significant difference in the incidence rate of dreaming with the type of anaesthesia used (Group Propo, 11 patients; Group Metho-Iso, 6 patients). CONCLUSIONS Dreaming during general anaesthesia is common but does not influence satisfaction or anxiety after anaesthesia.
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Affiliation(s)
- K Hellwagner
- University of Vienna, Department of Anaesthesia and General Intensive Care (A & B), Vienna, Austria.
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20
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Zeegers A, van Wilgenburg H, Leeuwin RS. Cardiac effects of benzodiazepine receptor agonists and antagonists in the isolated rat heart: a comparative study. Life Sci 1999; 63:1439-56. [PMID: 9952290 DOI: 10.1016/s0024-3205(98)00411-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Effects of PK 11195 and flumazenil on cardiac responses to diazepam, clonazepam and zolpidem were compared. Coronary flow rate was increased at relatively low doses of diazepam and decreased at higher doses. Clonazepam induced a dose-dependent increase, and zolpidem a decrease of coronary flow rate. PK 11195 reduced the diazepam-induced increase of coronary flow rate, and flumazenil was ineffective. Neither antagonist evoked substantial changes in the decrease of coronary flow rate. PK 11195, and less so flumazenil, antagonized the clonazepam-induced increase. PK 11195 and flumazenil only in their highest doses suppressed and respectively potentiated the zolpidem-induced decrease. Inotropy showed a biphasic response in the presence of diazepam, i.e. an initial transient decrease, followed by a dose-dependent increase in two steps. Clonazepam induced a similar response. Zolpidem increased the inotropy. The negative inotropic response induced by diazepam did not change significantly in the presence of PK 11195 or flumazenil. The positive inotropic response was suppressed by PK 11195, and less so by flumazenil. The negative response to clonazepam was antagonized by both PK 11195 and flumazenil; the positive response was not significantly changed. In the presence of lower doses of PK 11195, the zolpidem-induced response was potentiated, whereas higher doses produced reversal; flumazenil potentiated the response. In conclusion, the results support earlier suggestions, involving receptor mechanisms with cardiac effects of benzodiazepines. Both agonists and antagonists (inter)act in a different manner, suggesting that rather ambiguous receptor mechanisms are involved in benzodiazepine effects in the heart.
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Affiliation(s)
- A Zeegers
- Department of Pharmacology, University of Amsterdam, Academic Medical Center, The Netherlands
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21
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Okubo M, Kawaguchi M. Inhibitory regulation of amylase release in rat parotid acinar cells by benzodiazepine receptors. Eur J Pharmacol 1998; 359:243-9. [PMID: 9832396 DOI: 10.1016/s0014-2999(98)00628-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study examined the influence of benzodiazepine receptors on amylase release from rat parotid acinar cells. Diazepam (10(-8)-10(-6) M), which is a potent agonist of both central- and peripheral-type benzodiazepine receptors, dose dependently decreased amylase release induced by isoprenaline and carbachol, which are beta-adrenoceptor and muscarinic receptor agonists, respectively. The maximum inhibitory response was obtained with 10(-6) M diazepam: amylase release was decreased to 57% (isoprenaline) and 39% (carbachol) of maximal levels, while these responses were completely inhibited by propranolol and atropine, respectively. Clonazepam and 7-chloro-1,3-dihydro-1-methyl-5-p-chlorophenyl)-2H-1,4-benzodiazepine-2- one (Ro 5-4864), which are selective agonists of central- and peripheral-type benzodiazepine receptors, respectively, also produced a significant and dose-dependent decrease in isoprenaline-induced amylase release. The inhibitory potency was diazepam > clonazepam > Ro 5-4864. Flumazenil and 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide (PK 11195), which are selective antagonists of central- and peripheral-type benzodiazepine receptors, respectively, dose dependently blocked the inhibition of isoprenaline-induced amylase release by diazepam. At a concentration of 10(-5) M, flumazenil and PK 11195 restored amylase release to approximately 75% of that in the presence of isoprenaline alone. The combination of both antagonists completely prevented the inhibition by diazepam. Similarly, the inhibitory responses of clonazepam and Ro 5-4864 were completely blocked by flumazenil and PK 11195, respectively. These results suggest that, in rat parotid acinar cells, benzodiazepines inhibit beta-adrenoceptor and muscarinic receptor-stimulated amylase release and that both central- and peripheral-type benzodiazepine receptors contribute to this inhibitory regulation.
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Affiliation(s)
- M Okubo
- Department of Pharmacology and Oral Health Science Center, Tokyo Dental College, Chiba, Japan
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22
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Leeuwin RS, Zeegers A, van Hamme J, van Wilgenburg H. Modification of cardiac actions of RO 05-4864 by PK 11195 and flumazenil in the perfused rat heart. Life Sci 1997; 61:1631-42. [PMID: 9363978 DOI: 10.1016/s0024-3205(97)00768-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The benzodiazepine analogue Ro 05-4864 [chlorodiazepam] (2.10[-5] to 4.10[-4] M) induced a concentration-dependent increase of coronary flow rate (Emax 82.4% [+/- 2.2 SEM]) and an increase of contraction force (Emax 68.3% [+/- 4.7 SEM]) of the retrograde perfused, isolated Langendorff rat heart. The influence of PK 11195, antagonist of the peripheral type benzodiazepine receptor, and flumazenil (Anexate), antagonist of the central type benzodiazepine receptor, on these responses to Ro 5-4864 was studied. In concentrations of 10(-7) to 5.10(-5) M, PK 11195 significantly reduced both the increase of coronary flow rate and of contraction force, without affecting these functions by itself; the positive inotropic response produced by Ro 05-4864 was even abolished in the presence of 5.10(-5) M PK 11195. The Emax values of Ro 05-4864 on both coronary flow and inotropy were reduced significantly by PK 11195. In the presence of flumazenil, 10(-7) to 10(-5) M, both the vasodilatory and the positive inotropic response induced by Ro 05-4864 were significantly counteracted as well. The Emax values of Ro 05-4864 were reduced significantly. In conclusion, the results support earlier suggestions that it is tempting to involve peripheral type benzodiazepine receptors in cardiac actions of benzodiazepines. The finding that the centrally acting benzodiazepine antagonist flumazenil reduced the cardiac actions of Ro 05-4864 is as yet difficult to explain. On the other hand concentrations of both agonist and antagonist employed are so-much high that interference of other receptors than benzodiazepine receptors must be considered as well.
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Affiliation(s)
- R S Leeuwin
- Department of Pharmacology, University of Amsterdam, Academic Medical Centre, The Netherlands.
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23
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Campiani G, Nacci V, Fiorini I, De Filippis MP, Garofalo A, Ciani SM, Greco G, Novellino E, Manzoni C, Mennini T. New pyrrolobenzothiazepine derivatives as molecular probes of the ‘peripheral-type’ benzodiazepine receptor (PBR) binding site. Eur J Med Chem 1997. [DOI: 10.1016/s0223-5234(97)83975-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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24
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Campiani G, Nacci V, Fiorini I, De Filippis MP, Garofalo A, Ciani SM, Greco G, Novellino E, Williams DC, Zisterer DM, Woods MJ, Mihai C, Manzoni C, Mennini T. Synthesis, biological activity, and SARs of pyrrolobenzoxazepine derivatives, a new class of specific "peripheral-type" benzodiazepine receptor ligands. J Med Chem 1996; 39:3435-50. [PMID: 8784441 DOI: 10.1021/jm960251b] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The "peripheral-type" benzodiazepine receptor (PBR) has been reported to play a role in many biological processes. We have synthesized and tested a novel series of PBR ligands based on a pyrrolobenzoxazepine skeleton, in order to provide new receptor ligands. Several of these new compounds proved to be high affinity and selective ligands for PBR, and benzoxazepines 17f and 17j were found to be the most potent ligands for this receptor to have been identified to date. The SAR and the molecular modeling studies detailed herein delineated a number of structural features required for improving affinity. Some of the ligands were employed as "molecular yardsticks" to probe the spatial dimensions of the lipophilic pockets L1 and L3 in the PBR cleft and to determine the effect of occupation of L1 and L3 with respect to affinity, while other C-7 modified analogues provided information specifically on the hydrogen bonding with a putative receptor site H1. The new pyrrolobenzoxazepines were tested in rat cortex, a tissue expressing high density of mitochondrial PBR, and exhibited IC50 and Ki values in the low nanomolar or subnanomolar range, as measured by the displacement of [3H]PK 11195 binding. A subset of the highest affinity ligands was also found to have high affinities for [3H]PK 11195 and [3H]Ro 5-4864 binding in rat adrenal mitochondria. All the ligands in this subset are stimulators of steroidogenesis having similar potency and extent of stimulation as PK 11195 and Ro 5-4864 of steroidogenesis in the mouse Y-1 adrenocortical cell line.
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Affiliation(s)
- G Campiani
- Dipartimento Farmaco Chimico Tecnologico, Università di Siena, Italy
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25
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Campiani G, Fiorini I, De Filippis MP, Ciani SM, Garofalo A, Nacci V, Giorgi G, Sega A, Botta M, Chiarini A, Budriesi R, Bruni G, Romeo MR, Manzoni C, Mennini T. Cardiovascular characterization of pyrrolo[2,1-d][1,5]benzothiazepine derivatives binding selectively to the peripheral-type benzodiazepine receptor (PBR): from dual PBR affinity and calcium antagonist activity to novel and selective calcium entry blockers. J Med Chem 1996; 39:2922-38. [PMID: 8709127 DOI: 10.1021/jm960162z] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The synthesis and cardiovascular characterization of a series of novel pyrrolo[2,1-d][1,5]-benzothiazepine derivatives (54-68) are described. Selective peripheral-type benzodiazepine receptor (PBR) ligands, such as PK 11195 and Ro 5-4864, have recently been found to possess low but significant inhibitory activity of L-type calcium channels, and this property is implicated in the cardiovascular effects observed with these compounds. In functional studies both PK 11195 (1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxa mide) and Ro 5-4864 (4'-chlorodiazepam) did not display selectivity between cardiac and vascular tissue. Therefore, several 7-(acyloxy)-6-arylpyrrolo[2,1-d][1,5]benzothiazepines, potent and selective peripheral-type benzodiazepine receptor ligands recently developed by us (3, 7-20), were subjected to calcium channel receptor binding assay. Some of these compounds showed an unexpected potency in displacing the binding of [3H]nitrendipine from L-type calcium channels, much higher than that reported for PK 11195 and Ro 5-4864 and equal to or higher than that of reference calcium antagonists such as verapamil and (+)-cis-diltiazem. Specifically, in rat cortex homogenate, our prototypic PBR ligand 7-acetoxy-6-(p-methoxyphenyl)pyrrolo[2,1-d][1,5]benzothiazepine (3) showed an IC50 equal to 0.13 nM for inhibition of [3H]nitrendipine binding. Furthermore, in functional studies this compound displayed a clear-cut selectivity for cardiac over vascular tissue. Comparison of calcium antagonist activity on guinea pig aorta strips with the negative inotropic activity, determined by using isolated guinea pig left atria, revealed that 3 displayed higher selectivity than the reference (+)-cis-diltiazem. Thus, the pyrrolobenzothiazepine 3 might represent a new tool for characterizing the relationship between the PBR and cardiac function. Furthermore, we have also investigated the structural dependence of binding to PBR and L-type calcium channels, and this study allowed us to identify a new class of potent calcium channel blockers selective for cardiac over vascular tissue, with no affinity for PBR. A number of structure-activity relationship trends have been identified, and a possible explanation is advanced in order to account for the observed differences in selectivity. Three structural features, namely, (i) the saturation of the C(6)-C(7) double bond, with a consequent higher molecular flexibility, (ii) the presence of a substituent in the benzofused ring, and (iii) a basic side chain at C-10 of the pyrrolobenzothiazepine ring system, were found to be responsible for potent L-type calcium channel antagonism and clear-cut selectivity for cardiac over vascular tissue. Among the synthesized compounds the pyrrolobenzothiazepine 62 was found to be the most promising selective calcium channel blocker. Additionally, the molecular structure determination of the key intermediate 48 by X-ray diffraction, molecular modeling, and NMR analysis is reported.
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Affiliation(s)
- G Campiani
- Dipartimento Farmaco Chimico Technologico, Università di Siena, Italy
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26
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Krueger KE. Molecular and functional properties of mitochondrial benzodiazepine receptors. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1241:453-70. [PMID: 8547305 DOI: 10.1016/0304-4157(95)00016-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- K E Krueger
- Department of Cell Biology, Georgetown University School of Medicine, Washington, D.C. 20007, USA
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27
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Monasterolo LA, Ochoa JE, Trumper L, Elías MM. Vascular and tubular actions of diazepam in isolated and perfused rat kidney. Eur J Pharmacol 1995; 276:201-5. [PMID: 7601205 DOI: 10.1016/0014-2999(95)00019-h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effects of diazepam were studied in the isolated rat kidney under conditions of constant flow. Kidneys were perfused with modified Ringer-Krebs solution. Diazepam produced a raised fractional excretion of water and sodium without hemodynamic changes, suggesting a direct effect on tubular transport mechanisms. Diazepam decreased renal perfusion pressure in a concentration-dependent fashion when kidneys were pretreated with either noradrenaline or potassium chloride. Similar responses were observed when 7-chloro-5-[4-chloro-phenyl]-1, 3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one (Ro 5-4864) or clonazepam was used. These data provide evidence for a relaxant effect of benzodiazepines on preconstricted renal vasculature.
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Affiliation(s)
- L A Monasterolo
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Argentina
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28
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Chiou LC, Chang CC. Pharmacological relevance of peripheral type benzodiazepine receptors on motor nerve and skeletal muscle. Br J Pharmacol 1994; 112:257-61. [PMID: 8032647 PMCID: PMC1910319 DOI: 10.1111/j.1476-5381.1994.tb13060.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
1. Effects of agonists and antagonists of peripheral and central benzodiazepine receptors (pBZR and cBZR) on neuromuscular transmission were studied in mouse isolated phrenic nerve-diaphragm preparations. 2. Ro5-4864, a pBZR agonist, had no effect on the neuromuscular transmission but increased muscle contractility and antagonized the tetanic fade induced by neostigmine. 3. Ro5-4864 inhibited the regenerative tonic endplate depolarization caused by repetitive stimulation in the presence of neostigmine without affecting the amplitude and decay time of miniature and evoked single endplate potentials. 4. All the effects of Ro5-4864 were shared by PK11195, a pBZR antagonist, but not by clonazepam and flumazenil, a cBZR agonist and antagonist, respectively. 5. It is suggested that peripheral type benzodiazepine receptors modulate presynaptic function and muscle contraction.
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Affiliation(s)
- L C Chiou
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei
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29
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Smyth RJ, Uhlman EJ, Ruggieri MR. Identification and characterization of a high-affinity peripheral-type benzodiazepine receptor in rabbit urinary bladder. J Urol 1994; 151:1102-6. [PMID: 8126801 DOI: 10.1016/s0022-5347(17)35192-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The present study used radioligand binding and in vitro contractility experiments to identify and characterize a peripheral-type benzodiazepine receptor PBR in rabbit urinary bladder. [3H]PK11195 bound to bladder membranes with high-affinity and density (Kd = 5.2 nM., Bmax = 268 fmol./mg. protein), indicating the presence of a PBR. [3H]flunitrazepam bound with high-affinity and density (Kd = 1.2 nM., Bmax = 48 fmol./mg. protein). The rank order potency of various benzodiazepines and isoquinoline carboxamides in displacing the binding of [3H]PK11195 was Ro5-4864 > diazepam = flunitrazepam >> Ro15-1788 = clonazepam. Ro5-4864 and PK11195 inhibited nerve-evoked contractions in a concentration-dependent manner (IC50 = 42 microM. and 56 microM., respectively). Carbachol- and KCl-induced contractions were also inhibited by Ro5-4864 and PK11195. KCl-induced contractions were inhibited to a greater extent than carbachol-induced or field-stimulated contractions with all the drugs tested. Both Ro5-4864 and PK11195 significantly increased the ED50 for calcium-induced contractions following a cholinergic stimulus compared with control. These data demonstrate the presence of a PBR in urinary bladder capable of altering contractility in vitro through modulation of calcium activity.
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Affiliation(s)
- R J Smyth
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
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30
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Shany E, Hochhauser E, Halpern P, Vidne B, Gavish M, Geller E, Hasharoni A, Barak Y, Yakirevich V. Ro 5-4864 has a negative inotropic effect on human atrial muscle strips that is not antagonized by PK 11195. Eur J Pharmacol 1994; 253:231-6. [PMID: 8200417 DOI: 10.1016/0014-2999(94)90196-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The effects of Ro 5-4864, a peripheral benzodiazepine receptor agonist (9 x 10(-6) M and 9 x 10(-5) M) and of PK 11195, a peripheral benzodiazepine receptor antagonist (3 x 10(-6) M and 3 x 10(-5) M), alone or together, on contraction parameters of human atrial muscle strips were studied. Atrial muscle strips were obtained from patients undergoing cardiac surgery. The strips were suspended in Krebs-Henseleit solution at 36.8 +/- 0.2 degrees C, connected to an isometric force transducer and then stimulated at 15 V above threshold and paced at 1.5 Hz. Ro 5-4864 at its higher concentration, alone or mixed with PK 11195 at both concentrations, depressed the contraction amplitude to 80% of the control value (P < 0.05). In conclusion, Ro 5-4864 had a small but significant depressant effect on the contraction amplitude of human atrial strips. Surprisingly, this effect was not reversed by the peripheral benzodiazepine receptor antagonist PK 11195.
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Affiliation(s)
- E Shany
- Pediatric Division, Soroka Medical Center, Beersheba, Israel
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31
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Petit P, Manteghetti M, Berdeu D, Ribes G, Loubatières-Mariani MM. Effects of a peripheral-type benzodiazepine on glucose-induced insulin secretion. Eur J Pharmacol 1992; 221:359-63. [PMID: 1426011 DOI: 10.1016/0014-2999(92)90723-h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Benzodiazepines, besides interacting with central-type receptors which mediate their well-known pharmacological actions, bind to peripheral-type receptors that are distributed in a variety of peripheral tissues including numerous endocrine organs. The present work was designed to investigate the effects of a selective peripheral-type benzodiazepine, 4'-chlordiazepam (Ro 5-4864), on glucose-induced insulin secretion in vitro. In the rat isolated pancreas perfused with a Krebs-bicarbonate buffer containing 8.3 mM glucose, the drug (10(-6) and 10(-5) M) induced a progressive and significant decrease in insulin release. Concomitantly, it induced a vasodilator response of the pancreatic vascular bed. In rat isolated islets incubated for 1 h in the presence of 15 mM glucose, 4'-chlordiazepam (10(-5) and 10(-4) M) induced a significant and dose-dependent inhibition of insulin release. In contrast, the selective central-type benzodiazepine, clonazepam (10(-6) - 10(-4) M), did not significantly modify glucose-induced insulin secretion. In addition, experiments were performed to test the effect of 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline-carboxamid e (PK 11195), a peripheral non-benzodiazepine ligand proposed as a putative antagonist. This substance did not counteract the inhibitory effect of 4'-chlordiazepam but itself (10(-6) and 10(-5) M) elicited a potent inhibitory effect on insulin secretion. These results show that drugs such as 4'-chlordiazepam and PK 11195 which have a high affinity for peripheral-type benzodiazepine receptors, in contrast to a central-type benzodiazepine agonist, inhibit glucose-induced insulin secretion in vitro.
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Affiliation(s)
- P Petit
- Faculté de Médecine, Laboratoire de Pharmacologie, URA 599 du CNRS, Montpellier, France
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32
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Gavish M, Katz Y, Bar-Ami S, Weizman R. Biochemical, physiological, and pathological aspects of the peripheral benzodiazepine receptor. J Neurochem 1992; 58:1589-601. [PMID: 1313848 DOI: 10.1111/j.1471-4159.1992.tb10030.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The PBR is a mitochondrial protein composed of at least two subunits, an approximately 30-kDa subunit that contains the site for BZs and an approximately 18-kDa subunit that binds isoquinoline carboxamide derivatives. Porphyrins and diazepam binding inhibitor are putative endogenous ligands for these receptors, which are under neural and hormonal control. Alterations in the density of PBR seem to be a sensitive indicator of stress: up-regulation after acute stress and down-regulation induced by repeated stress. PBR-specific ligands are involved in the control of cell proliferation and differentiation, and their binding is increased in some cancer tumors. Numerous studies in various endocrine organs have revealed that PBR are located in specific regions or tissues in the organs. Furthermore, PBR densities in various organs subject to hormonal control are regulated by organotropic hormones. At least in some cases, BZ ligands do not exert a specific effect in an organ, but rather modulate the well-documented effects of that particular hormone. To the best of our knowledge, BZ ligand action in peripheral tissues is dependent on recognition of PBR, which may suggest a receptor-mediated action.
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Affiliation(s)
- M Gavish
- Rappapport Family Institute for Research in the Medical Sciences, Rambam Medical Center, Haifa, Israel
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33
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Moreno-Sánchez R, Hogue BA, Bravo C, Newman AH, Basile AS, Chiang PK. Inhibition of substrate oxidation in mitochondria by the peripheral-type benzodiazepine receptor ligand AHN 086. Biochem Pharmacol 1991; 41:1479-84. [PMID: 1850277 DOI: 10.1016/0006-2952(91)90564-l] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects, of the benzodiazepines RO5-4864, AHN 086, PK 11195 and clonazepam on respiration of mitochondria from heart, kidney, and liver were studied. ADP-stimulated respiration of heart mitochondria was the most sensitive to inhibition by AHN 086; clonazepam was not inhibitory. Several respiratory chain segment activities of submitochondrial particles were insensitive to AHN 086, except for NADH oxidase which was partially inhibited. However, in contrast to submitochondrial particles, the succinate-cytochrome c oxidoreductase activity in intact mitochondria was inhibited by AHN 086, suggesting an effect at the substrate transport level. Phosphate-induced, succinate-dependent swelling was also inhibited by AHN 086 it was not affected by clonazepam. Uncoupled ATP hydrolysis was partially inhibited by RO5-4864, AHN 086, and clonazepam. It is suggested that there is an unspecific inhibition of NADH oxidase and ATP hydrolysis by these benzodiazepines and a specific inhibition on oxidizable substrate transport by the peripheral-type benzodiazepine AHN 086.
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34
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Moreno-Sánchez R, Bravo C, Gutiérrez J, Newman AH, Chiang PK. Release of Ca2+ from heart and kidney mitochondria by peripheral-type benzodiazepine receptor ligands. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1991; 23:207-13. [PMID: 1847885 DOI: 10.1016/0020-711x(91)90191-o] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
1. The effect of the benzodiazepines Ro5-4864, AHN 086 and clonazepam on the release of Ca2+ from rat heart and kidney mitochondria was studied. 2. The peripheral-type benzodiazepines Ro5-4864 and AHN 086 induced Ca2+ release which was blocked by Mg2+ whereas the central-type benzodiazepine clonazepam was ineffective. 3. An associated collapse of membrane potential and swelling were also induced by AHN 086 in the presence of Ca2+. 4. However, no oxidation of pyridine nucleotides or increased rate or respiration were observed. 5. Release of Sr2+ was induced by AHN 086 in the absence of inorganic phosphate but not in its presence. 6. These data are discussed in the context of the current hypotheses on the mechanism of mitochondrial Ca2+ release.
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Affiliation(s)
- R Moreno-Sánchez
- Departamento de Bioquímica, Instituto Nacional de Cardiología, México, D.F
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35
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Kazanietz MG, Elgoyhen AB. Relaxant effect of benzodiazepines on uterine rings isolated from estrogen-treated rats. Eur J Pharmacol 1990; 185:231-4. [PMID: 1979275 DOI: 10.1016/0014-2999(90)90646-n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
K(+)-contracted rat uterine rings were relaxed in a concentration-dependent manner by the benzodiazepines Ro 5-4864, diazepam and clonazepam, as well as by the putative peripheral benzodiazepine antagonist PK 11195. The relaxation induced by diazepam was not counteracted by the central antagonist Ro 15-1788 (10 microM), and the relaxant effects of Ro 5-4864 and of diazepam were not prevented by either the GABAA antagonist bicuculline (10 microM) or the beta-adrenoceptor antagonist propranolol (1 microM). The mechanism underlying the relaxant effects of benzodiazepines on K(+)-contracted uterine rings is still under study.
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Affiliation(s)
- M G Kazanietz
- Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, UBA, Buenos Aires, Argentina
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36
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Marano G, Massotti M, Spagnolo A, Carpi A. Enhancement of pharmacologically induced bronchoconstriction by Ro 5-4864. Eur J Pharmacol 1990; 179:237-40. [PMID: 2364987 DOI: 10.1016/0014-2999(90)90426-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Pretreatment with Ro 5-4864 enhanced the bronchoconstrictor responses to histamine or carbachol in the anaesthetized artificially ventilated guinea pig. This suggests the involvement of a peripheral-type benzodiazepine receptor as also indicated by the lack of effect of clonazepam. PK 11195 did not antagonize the Ro 5-4864-induced enhancement, but itself enhanced the bronchoconstrictor responses to histamine or carbachol. The data indicate that Ro 5-4864 and PK 11195 behave as metactoid sensitizers of histamine or carbachol.
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Affiliation(s)
- G Marano
- Laboratorio di Farmacologia, Instituto Superiore di Sanità, Roma, Italy
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Ferry A, Jaillon P, Lecocq B, Lecocq V, Jozefczak C. Pharmacokinetics and effects on exercise heart rate of PK 11195 (52028 RP), an antagonist of peripheral benzodiazepine receptors, in healthy volunteers. Fundam Clin Pharmacol 1989; 3:383-92. [PMID: 2553568 DOI: 10.1111/j.1472-8206.1989.tb00679.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PK 11195 (or 52028 RP; 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide), an antagonist of the peripheral-type benzodiazepine receptors which are coupled to calcium channels, was administered to 10 healthy volunteers in order to study the pharmacokinetics and cardiovascular effects of the drug. PK 11195 was randomly administered intravenously (10 mg) and orally in three single dosages (100, 200 and 400 mg). Placebo was only given orally. Heart rate and blood pressure were recorded at rest and during exercise tests which were performed at 0, 1, 3, 6 and 24 h after dosing on each study day. The results showed that after IV administration, PK 11195 was rapidly distributed in two or three open compartments. Its elimination T 1/2 was short (3.7 +/- 3.0 h) with high interindividual variability. After oral ingestion the pharmacokinetics of PK 11195 were linear over the range of 100-400 mg single oral doses with a stable absolute bioavailability (33%). T 1/2 elimination was prolonged (7-12 h) and the presence of secondary increases in plasma concentration at 8-10 h and 22-24 h after drug absorption may have been related to enterohepatic cycling. No unchanged PK 11195 could be detected in urine. PK 11195 did not significantly modify heart rate and blood pressure at rest or during exercise and was well tolerated by the subjects. These data suggest a high inter-individual variability in PK 11195 disposition with extensive metabolism in normal exercising volunteers.
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Affiliation(s)
- A Ferry
- Unité de Pharmacologie Clinique, Hôpital Saint-Antoine, Paris, France
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Elgoyhen B, Adler-Graschinsky E. Diminution by benzodiazepines of the chronotropic responses to noradrenaline in rat isolated atria. Eur J Pharmacol 1989; 164:467-78. [PMID: 2475348 DOI: 10.1016/0014-2999(89)90254-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effects of various benzodiazepines on chronotropic responses were assayed in spontaneously beating rat isolated atria. The increases in atrial rate obtained from concentration-response curves to noradrenaline were reduced dose dependently by both the peripheral agonist, Ro 5-4864 5 and 10 microM, and the mixed agonist, diazepam 5, 10 and 50 microM, but not by the central benzodiazepine agonist, clonazepam 10 and 30 microM. The inhibitory effects of the benzodiazepines on the atrial responses to noradrenaline were not counteracted by either the peripheral benzodiazepine antagonist, PK 11195 10 microM, or the central benzodiazepine antagonist, Ro 15-1788 10 and 100 microM. Both 10 microM Ro 5-4864 and 10 microM diazepam also reduced the increases in atrial rate produced by either the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine, or the adenylate cyclase activator, forskolin. On the contrary, diazepam and Ro 5-4864 did not modify the chronotropic responses of the atria either to direct exposure to CaCl2 or to the calcium agonist, BAY K 8644. The increases in the intracellular levels of cAMP induced by noradrenaline were not modified by Ro 5-4864 and were even increased by 50% in the presence of diazepam. It is concluded that benzodiazepines probably reduce the chronotropic responses to noradrenaline in rat isolated atria through the interaction with the cAMP-linked chain of events that follows the activation of beta-adrenoceptors.
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Affiliation(s)
- B Elgoyhen
- Instituto de Investigaciones Farmacológicas, CONICET, Buenos Aires, Argentina
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Affiliation(s)
- V Saano
- Department of Pharmacology and Toxicology, University of Kuopio, Finland
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Mihara S, Fujimoto M. High-affinity binding sites for PK 11195, but not for RO5-4864, in porcine aortic smooth muscle. Life Sci 1989; 44:1713-20. [PMID: 2733549 DOI: 10.1016/0024-3205(89)90488-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Peripheral benzodiazepine (BZ) binding sites were characterized in porcine aortic smooth muscle membrane preparation. [3H]PK11195 bound with high affinity to the membranes (Kd = 8.6 + 0.9 nM), whereas [3H]Ro5-4864 bound slightly to the membranes. The Ki value of Ro5-4864 obtained from the inhibition of [3H]PK 11195 binding was 1200 + 200 nM, which was 480 times weaker than that obtained in rat kidney. Furthermore, the Ro5-4864 effect was temperature-insensitive. When [3H]PK 11195 binding was examined in porcine, human and rat platelets, Ro5-4864 inhibited the binding in porcine and human platelets one order of magnitude less potently than that in rat platelets. These results suggest that low affinity for Ro5-4864 in porcine aorta smooth muscle originates in porcine tissue, but not in smooth muscle.
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Affiliation(s)
- S Mihara
- Shionogi Research Laboratories, Shionogi & Co. Ltd., Osaka, Japan
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