1
|
Theiner T, Ortner NJ, Oberacher H, Stojanovic G, Tuluc P, Striessnig J. Novel protocol for multiple-dose oral administration of the L-type Ca 2+ channel blocker isradipine in mice: A dose-finding pharmacokinetic study. Channels (Austin) 2024; 18:2335469. [PMID: 38564754 PMCID: PMC10989688 DOI: 10.1080/19336950.2024.2335469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/21/2024] [Indexed: 04/04/2024] Open
Abstract
Studies in genetically modified animals and human genetics have recently provided new insight into the role of voltage-gated L-type Ca2+ channels in human disease. Therefore, the inhibition of L-type Ca2+ channels in vivo in wildtype and mutant mice by potent dihydropyridine (DHP) Ca2+ channel blockers serves as an important pharmacological tool. These drugs have a short plasma half-life in humans and especially in rodents and show high first-pass metabolism upon oral application. In the vast majority of in vivo studies, they have therefore been delivered through parenteral routes, mostly subcutaneously or intraperitoneally. High peak plasma concentrations of DHPs cause side effects, evident as DHP-induced aversive behaviors confounding the interpretation of behavioral readouts. Nevertheless, pharmacokinetic data measuring the exposure achieved with these applications are sparse. Moreover, parenteral injections require animal handling and can be associated with pain, discomfort and stress which could influence a variety of physiological processes, behavioral and other functional readouts. Here, we describe a noninvasive oral application of the DHP isradipine by training mice to quickly consume small volumes of flavored yogurt that can serve as drug vehicle. This procedure does not require animal handling, allows repeated drug application over several days and reproducibly achieves peak plasma concentrations over a wide range previously shown to be well-tolerated in humans. This protocol should facilitate ongoing nonclinical studies in mice exploring new indications for DHP Ca2+ channel blockers.
Collapse
Affiliation(s)
- Tamara Theiner
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Nadine J. Ortner
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Herbert Oberacher
- Institute of Legal Medicine and Core Facility Metabolomics, Medical University of Innsbruck, Innsbruck, Austria
| | - Gospava Stojanovic
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| |
Collapse
|
2
|
Lima ALD, Silva EG, Cardozo PL, da Silva MCM, Koerich S, Ribeiro FM, Moreira FA, Vieira LB. Isradipine, an L-type calcium channel blocker, attenuates cocaine effects in mice by reducing central glutamate release. Eur J Pharmacol 2024; 971:176489. [PMID: 38492875 DOI: 10.1016/j.ejphar.2024.176489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 02/15/2024] [Accepted: 03/11/2024] [Indexed: 03/18/2024]
Abstract
Substance abuse disorder is a chronic condition for which pharmacological treatment options remain limited. L-type calcium channels (LTCC) have been implicated in drug-related plasticity and behavior. Specifically, dopaminergic neurons in the mesocorticolimbic pathway express Cav1.2 and Cav1.3 channels, which may regulate dopaminergic activity associated with reward behavior. Therefore, this study aimed to investigate the hypothesis that pre-administration of the LTCC blocker, isradipine can mitigate the effects of cocaine by modulating central glutamatergic transmission. For that, we administered isradipine at varying concentrations (1, 7.5, and 15 μg/μL) via intracerebroventricular injection in male Swiss mice. This pretreatment was carried out prior to subjecting animals to behavioral assessments to evaluate cocaine-induced locomotor sensitization and conditioned place preference (CPP). The results revealed that isradipine administered at a concentration of 1 μg/μL effectively attenuated both the sensitization and CPP induced by cocaine (15 mg/kg, via i. p.). Moreover, mice treated with 1 μg/μL of isradipine showed decreased presynaptic levels of glutamate and calcium in the cortex and hippocampus as compared to control mice following cocaine exposure. Notably, the gene expression of ionotropic glutamate receptors, AMPA, and NMDA, remained unchanged, as did the expression of Cav1.2 and Cav1.3 channels. Importantly, these findings suggest that LTCC blockage may inhibit behavioral responses to cocaine, most likely by decreasing glutamatergic input in areas related to addiction.
Collapse
Affiliation(s)
- Anna Luiza Diniz Lima
- Department of Pharmacology, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Emanuele Guimarães Silva
- Department of Immunology and Biochemistry, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Pablo Leal Cardozo
- Department of Immunology and Biochemistry, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | - Suélyn Koerich
- Department of Pharmacology, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Fabíola Mara Ribeiro
- Department of Immunology and Biochemistry, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Fabrício A Moreira
- Department of Pharmacology, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Luciene Bruno Vieira
- Department of Pharmacology, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
| |
Collapse
|
3
|
Brimblecombe KR, Connor-Robson N, Bataille CJR, Roberts BM, Gracie C, O'Connor B, Te Water Naude R, Karthik G, Russell AJ, Wade-Martins R, Cragg SJ. Inhibition of striatal dopamine release by the L-type calcium channel inhibitor isradipine co-varies with risk factors for Parkinson's. Eur J Neurosci 2024; 59:1242-1259. [PMID: 37941514 DOI: 10.1111/ejn.16180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/25/2023] [Accepted: 10/14/2023] [Indexed: 11/10/2023]
Abstract
Ca2+ entry into nigrostriatal dopamine (DA) neurons and axons via L-type voltage-gated Ca2+ channels (LTCCs) contributes, respectively, to pacemaker activity and DA release and has long been thought to contribute to vulnerability to degeneration in Parkinson's disease. LTCC function is greater in DA axons and neurons from substantia nigra pars compacta than from ventral tegmental area, but this is not explained by channel expression level. We tested the hypothesis that LTCC control of DA release is governed rather by local mechanisms, focussing on candidate biological factors known to operate differently between types of DA neurons and/or be associated with their differing vulnerability to parkinsonism, including biological sex, α-synuclein, DA transporters (DATs) and calbindin-D28k (Calb1). We detected evoked DA release ex vivo in mouse striatal slices using fast-scan cyclic voltammetry and assessed LTCC support of DA release by detecting the inhibition of DA release by the LTCC inhibitors isradipine or CP8. Using genetic knockouts or pharmacological manipulations, we identified that striatal LTCC support of DA release depended on multiple intersecting factors, in a regionally and sexually divergent manner. LTCC function was promoted by factors associated with Parkinsonian risk, including male sex, α-synuclein, DAT and a dorsolateral co-ordinate, but limited by factors associated with protection, that is, female sex, glucocerebrosidase activity, Calb1 and ventromedial co-ordinate. Together, these data show that LTCC function in DA axons and isradipine effect are locally governed and suggest they vary in a manner that in turn might impact on, or reflect, the cellular stress that leads to parkinsonian degeneration.
Collapse
Affiliation(s)
- Katherine R Brimblecombe
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, Maryland, USA
| | - Natalie Connor-Robson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK
| | - Carole J R Bataille
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Bradley M Roberts
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK
| | - Caitlin Gracie
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Bethan O'Connor
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | | | - Gayathri Karthik
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Angela J Russell
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Richard Wade-Martins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, Maryland, USA
| | - Stephanie J Cragg
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, Maryland, USA
| |
Collapse
|
4
|
Choi S, Methiwala HN, Graves SM. Isradipine, an L-type calcium channel inhibitor, attenuates cue-associated methamphetamine-seeking in mice. Brain Res 2023; 1818:148528. [PMID: 37567548 PMCID: PMC10530265 DOI: 10.1016/j.brainres.2023.148528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/02/2023] [Accepted: 08/08/2023] [Indexed: 08/13/2023]
Abstract
Methamphetamine (meth) is an addictive psychostimulant and there are no FDA-approved treatment options for patients suffering from meth use disorders. In addition to being addictive, meth is also neurotoxic and chronic administration results in degeneration of substantia nigra pars compacta (SNc) dopamine and locus coeruleus (LC) norepinephrine neurons in mice. Optimal treatment strategies for meth use disorders would attenuate maladaptive meth-seeking behavior as well as provide neuroprotection. The L-type calcium channel inhibitor isradipine and the monoamine oxidase (MAO) inhibitor rasagiline both prevent chronic meth-induced SNc and LC degeneration but effects on meth-seeking are unknown. To test whether these clinically available compounds can mitigate meth-seeking, mice were implanted with chronic indwelling jugular vein catheters and allowed to self-administer meth (0.1 mg/kg/infusion) for 10 consecutive days (2-hrs/day) on a fixed ratio (FR) 1 schedule of reinforcement with meth infusions paired to a cue light. One day after the last self-administration session mice were tested for cue-associated meth-seeking behavior wherein the meth-associated cue light was contingently presented but meth reinforcement withheld. Isradipine (3 mg/kg) attenuated cue-associated meth-seeking in both male and female mice. In contrast, rasagiline (1 mg/kg) had no effect on seeking in either sex. These results suggest that isradipine may have the potential to serve as a dual-purpose pharmacotherapy for meth use disorders by attenuating seeking behavior and providing neuroprotection.
Collapse
Affiliation(s)
- Sanghoon Choi
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | | | - Steven M Graves
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA.
| |
Collapse
|
5
|
Natal S, Young CC, Kaur K, Gebhardt ES, Perrone A, Morikawa H, Tirado C, Smits JAJ. Applications of isradipine in human addiction studies: A systematic literature review. Exp Clin Psychopharmacol 2023; 31:507-522. [PMID: 36595455 PMCID: PMC10152997 DOI: 10.1037/pha0000633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Given the personal and public health burden of addictive disorders, innovative approaches to treatment are sorely needed. This systematic review examined the use of the pharmacological agent isradipine in the context of potential applications for addiction treatment. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guided a comprehensive search of PubMed, Cochrane Library, and PsycINFO between the years 1985 to July 2022. Studies were included if isradipine was administered to adults with a current Diagnostic and Statistical Manual of Mental Disorders-5th edition diagnosis of a substance use disorder and/or to healthy volunteers alone and in conjunction with a substance (i.e, cocaine, methamphetamine, alcohol). A total of 16 studies with 252 participants were included in this review. Substantial variability was identified with study designs, isradipine dosages/dosing, and addictive substance of interest. Outcomes clustered in four categories: (a) cerebral blood flow (CBF), (b) hemodynamic effects, (c) subjective effects, and (d) cognitive effects. Isradipine was found to improve CBF in individuals with cocaine-induced hypoperfusion and in several studies was found to reduce parameters of blood pressure elevation after stimulant use. There were no significant findings on isradipine's effect on subjective reporting (i.e., craving, mood, drug affect) or cognition/attention. Given the limited number of studies identified in this review, there is insufficient data to draw clear conclusions. The direct effects of isradipine as a pharmacologic agent for addictive disorder treatment appear minimal, however, future work may benefit from examining the impact of isradipine as an augmentative agent within existing cue exposure paradigms for preventing cue-induced drug relapse. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
Collapse
Affiliation(s)
- Samantha Natal
- Department of Psychology, The University of Texas at Austin, Austin Texas
| | - Cara C. Young
- School of Nursing, The University of Texas at Austin, Austin Texas
| | - Karamveer Kaur
- Department of Psychology, The University of Texas at Austin, Austin Texas
| | - Eli S. Gebhardt
- Department of Psychology, The University of Texas at Austin, Austin Texas
| | - Alexander Perrone
- Department of Psychology, The University of Texas at Austin, Austin Texas
| | - Hitoshi Morikawa
- Department of Neuroscience, The University of Texas at Austin, Austin Texas
| | - Carlos Tirado
- School of Pharmacy, The University of Texas at Austin, Austin Texas
| | - Jasper A. J. Smits
- Department of Psychology, The University of Texas at Austin, Austin Texas
| |
Collapse
|
6
|
Prager EM, Dorman DB, Hobel ZB, Malgady JM, Blackwell KT, Plotkin JL. Dopamine Oppositely Modulates State Transitions in Striosome and Matrix Direct Pathway Striatal Spiny Neurons. Neuron 2020; 108:1091-1102.e5. [PMID: 33080228 PMCID: PMC7769890 DOI: 10.1016/j.neuron.2020.09.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 07/29/2020] [Accepted: 09/21/2020] [Indexed: 12/18/2022]
Abstract
Corticostriatal synaptic integration is partitioned among striosome (patch) and matrix compartments of the dorsal striatum, allowing compartmentalized control of discrete aspects of behavior. Despite the significance of such organization, it's unclear how compartment-specific striatal output is dynamically achieved, particularly considering new evidence that overlap of afferents is substantial. We show that dopamine oppositely shapes responses to convergent excitatory inputs in mouse striosome and matrix striatal spiny projection neurons (SPNs). Activation of postsynaptic D1 dopamine receptors promoted the generation of long-lasting synaptically evoked "up-states" in matrix SPNs but opposed it in striosomes, which were more excitable under basal conditions. Differences in dopaminergic modulation were mediated, in part, by dendritic voltage-gated calcium channels (VGCCs): pharmacological manipulation of L-type VGCCs reversed compartment-specific responses to D1 receptor activation. These results support a novel mechanism for the selection of striatal circuit components, where fluctuating levels of dopamine shift the balance of compartment-specific striatal output.
Collapse
Affiliation(s)
- Eric M Prager
- Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA
| | - Daniel B Dorman
- Interdisciplinary Program in Neuroscience, George Mason University, Fairfax, VA 22030, USA
| | - Zachary B Hobel
- Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA
| | - Jeffrey M Malgady
- Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA
| | - Kim T Blackwell
- Interdisciplinary Program in Neuroscience, George Mason University, Fairfax, VA 22030, USA; Bioengineering Department, Volgenau School of Engineering, George Mason University, Fairfax, VA 22030, USA
| | - Joshua L Plotkin
- Department of Neurobiology and Behavior, Center for Nervous System Disorders, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA.
| |
Collapse
|
7
|
Hotka M, Cagalinec M, Hilber K, Hool L, Boehm S, Kubista H. L-type Ca 2+ channel-mediated Ca 2+ influx adjusts neuronal mitochondrial function to physiological and pathophysiological conditions. Sci Signal 2020; 13:eaaw6923. [PMID: 32047116 PMCID: PMC7116774 DOI: 10.1126/scisignal.aaw6923] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
L-type voltage-gated Ca2+ channels (LTCCs) are implicated in neurodegenerative processes and cell death. Accordingly, LTCC antagonists have been proposed to be neuroprotective, although this view is disputed, because intentional LTCC activation can also have beneficial effects. LTCC-mediated Ca2+ influx influences mitochondrial function, which plays a crucial role in the regulation of cell viability. Hence, we investigated the effect of modulating LTCC-mediated Ca2+ influx on mitochondrial function in cultured hippocampal neurons. To activate LTCCs, neuronal activity was stimulated by increasing extracellular K+ or by application of the GABAA receptor antagonist bicuculline. The activity of LTCCs was altered by application of an agonistic (Bay K8644) or an antagonistic (isradipine) dihydropyridine. Our results demonstrated that activation of LTCC-mediated Ca2+ influx affected mitochondrial function in a bimodal manner. At moderate stimulation strength, ATP synthase activity was enhanced, an effect that involved Ca2+-induced Ca2+ release from intracellular stores. In contrast, high LTCC-mediated Ca2+ loads led to a switch in ATP synthase activity to reverse-mode operation. This effect, which required nitric oxide, helped to prevent mitochondrial depolarization and sustained increases in mitochondrial Ca2+ Our findings indicate a complex role of LTCC-mediated Ca2+ influx in the tuning and maintenance of mitochondrial function. Therefore, the use of LTCC inhibitors to protect neurons from neurodegeneration should be reconsidered carefully.
Collapse
Affiliation(s)
- Matej Hotka
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria.
| | - Michal Cagalinec
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria
- Department of Cellular Cardiology, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Dúbravská cesta 9, 845 05 Bratislava, Slovakia
- Laboratory of Mitochondrial Dynamics, Department of Pharmacology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, University of Tartu, Ravila 19, 50 411 Tartu, Estonia
| | - Karlheinz Hilber
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria
| | - Livia Hool
- School of Human Sciences (Physiology), The University of Western Australia, Crawley, WA 6009, Australia
- Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia
| | - Stefan Boehm
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria
| | - Helmut Kubista
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria.
| |
Collapse
|
8
|
Vaz RL, Sousa S, Chapela D, van der Linde HC, Willemsen R, Correia AD, Outeiro TF, Afonso ND. Identification of antiparkinsonian drugs in the 6-hydroxydopamine zebrafish model. Pharmacol Biochem Behav 2019; 189:172828. [PMID: 31785245 DOI: 10.1016/j.pbb.2019.172828] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 11/12/2019] [Accepted: 11/13/2019] [Indexed: 01/09/2023]
Abstract
Parkinson's disease (PD) is known as a movement disorder due to characteristic motor features. Existing therapies for PD are only symptomatic, and their efficacy decreases as disease progresses. Zebrafish, a vertebrate in which parkinsonism has been modelled, offers unique features for the identification of molecules with antiparkinsonian properties. Here, we developed a screening assay for the selection of neuroactive agents with antiparkinsonian potential. First, we performed a pharmacological validation of the phenotypes exhibited by the 6-hydroxydopamine zebrafish model, by testing the effects of known antiparkinsonian agents. These drugs were also tested for disease-modifying properties by whole mount immunohistochemistry to TH+ neurons and confocal microscopy in the dopaminergic diencephalic cluster of zebrafish. Next, we optimized a phenotypic screening using the 6-hydroxydopamine zebrafish model and tested 1600 FDA-approved bioactive drugs. We found that 6-hydroxydopamine-lesioned zebrafish larvae exhibit bradykinetic and dyskinetic-like behaviours that are rescued by the administration of levodopa, rasagiline, isradipine or amantadine. The rescue of dopaminergic cell loss by isradipine was also verified, through the observation of a higher number of TH+ neurons in 6-OHDA-lesioned zebrafish larvae treated with this compound as compared to untreated lesioned larvae. The phenotypic screening enabled us to identify several compounds previously positioned for PD, as well as, new molecules with potential antiparkinsonian properties. Among these, we selected stavudine, tapentadol and nabumetone as the most promising candidates. Our results demonstrate the functional similarities of the motor impairments exhibited by 6-hydroxydopamine-lesioned zebrafish with mammalian models of PD and with PD patients, and highlights novel molecules with antiparkinsonian potential.
Collapse
Affiliation(s)
- Rita L Vaz
- TechnoPhage, SA, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal; Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Sara Sousa
- TechnoPhage, SA, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal.
| | - Diana Chapela
- TechnoPhage, SA, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | | | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands
| | - Ana D Correia
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany; CEDOC, Chronic Diseases Research Centre, NOVA Medical School |Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal.; Max Planck Institute for Experimental Medicine, Göttingen, Germany; Institute of Neuroscience, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Nuno D Afonso
- TechnoPhage, SA, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal.
| |
Collapse
|
9
|
Wong HTC, Zhang Q, Beirl AJ, Petralia RS, Wang YX, Kindt K. Synaptic mitochondria regulate hair-cell synapse size and function. eLife 2019; 8:e48914. [PMID: 31609202 PMCID: PMC6879205 DOI: 10.7554/elife.48914] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 10/13/2019] [Indexed: 11/21/2022] Open
Abstract
Sensory hair cells in the ear utilize specialized ribbon synapses. These synapses are defined by electron-dense presynaptic structures called ribbons, composed primarily of the structural protein Ribeye. Previous work has shown that voltage-gated influx of Ca2+ through CaV1.3 channels is critical for hair-cell synapse function and can impede ribbon formation. We show that in mature zebrafish hair cells, evoked presynaptic-Ca2+ influx through CaV1.3 channels initiates mitochondrial-Ca2+ (mito-Ca2+) uptake adjacent to ribbons. Block of mito-Ca2+ uptake in mature cells depresses presynaptic-Ca2+ influx and impacts synapse integrity. In developing zebrafish hair cells, mito-Ca2+ uptake coincides with spontaneous rises in presynaptic-Ca2+ influx. Spontaneous mito-Ca2+ loading lowers cellular NAD+/NADH redox and downregulates ribbon size. Direct application of NAD+ or NADH increases or decreases ribbon size respectively, possibly acting through the NAD(H)-binding domain on Ribeye. Our results present a mechanism where presynaptic- and mito-Ca2+ couple to confer proper presynaptic function and formation.
Collapse
MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Animals, Genetically Modified
- Calcium/metabolism
- Calcium Channel Agonists/pharmacology
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Calcium Signaling
- Cell Size
- Embryo, Nonmammalian
- Evoked Potentials, Auditory/physiology
- Eye Proteins/chemistry
- Eye Proteins/genetics
- Eye Proteins/metabolism
- Gene Expression
- Hair Cells, Auditory/cytology
- Hair Cells, Auditory/drug effects
- Hair Cells, Auditory/metabolism
- Isradipine/pharmacology
- Mitochondria/drug effects
- Mitochondria/metabolism
- Mitochondria/ultrastructure
- NAD/metabolism
- Oxidation-Reduction
- Protein Binding
- Protein Interaction Domains and Motifs
- Ruthenium Compounds/pharmacology
- Synapses/drug effects
- Synapses/metabolism
- Synapses/ultrastructure
- Synaptic Transmission
- Zebrafish
- Zebrafish Proteins/agonists
- Zebrafish Proteins/antagonists & inhibitors
- Zebrafish Proteins/chemistry
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism
Collapse
Affiliation(s)
- Hiu-tung C Wong
- Section on Sensory Cell Development and FunctionNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
- National Institutes of Health-Johns Hopkins University Graduate Partnership ProgramNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Qiuxiang Zhang
- Section on Sensory Cell Development and FunctionNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Alisha J Beirl
- Section on Sensory Cell Development and FunctionNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Ronald S Petralia
- Advanced Imaging CoreNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Ya-Xian Wang
- Advanced Imaging CoreNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Katie Kindt
- Section on Sensory Cell Development and FunctionNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| |
Collapse
|
10
|
Khuansuwan S, Barnhill LM, Cheng S, Bronstein JM. A novel transgenic zebrafish line allows for in vivo quantification of autophagic activity in neurons. Autophagy 2019; 15:1322-1332. [PMID: 30755067 PMCID: PMC6613892 DOI: 10.1080/15548627.2019.1580511] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 01/03/2019] [Accepted: 01/11/2019] [Indexed: 12/22/2022] Open
Abstract
The pathophysiology of most neurodegenerative diseases includes aberrant accumulation of protein aggregates. Recent evidence highlights the role of protein degradation pathways in neurodegeneration. Concurrently, genetic tools have been generated to enable zebrafish, Danio rerio, to be used as an animal model to study neurodegenerative processes. In addition to optical clarity and fast ex utero development, the zebrafish brain is relatively small and has conserved structures with its mammalian counterparts. To take advantage of this model organism and to aid further studies on autophagy and neurodegeneration, we created a stable transgenic zebrafish line that expresses eGFP-Map1lc3b specifically in post-mitotic neurons under the elavl3 promoter. This line is useful for indirectly monitoring autophagic activity in neurons in vivo and screening for macroautophagy/autophagy-modulating compounds. We determined the applicability of this transgenic line by modulating and quantifying the number of autophagosomes via treatment with a known autophagy inducer (rapamycin) and inhibitors (3-methyladenine, protease inhibitors). Additionally, we proposed an in vivo method for quantifying rates of autophagosome accumulation, which can be used to infer occurrence of autophagic flux. Last, we tested two FDA-approved drugs currently undergoing clinical studies for Parkinson disease, isradipine and nilotinib, and found that isradipine did not modulate autophagy, whereas nilotinib induced both autophagosome number and autophagic flux. It is hoped that others will find this line useful as an in vivo vertebrate model to find or validate autophagy modulators that might be used to halt the progression of neurodegenerative diseases. Abbreviations: 3MA: 3-methyladenine; BafA: bafilomycin A1; dd: dorsal diencephalon; dpf: days post fertilization; e: eye; eGFP: enhanced green fluorescent protein; Elavl3: ELAV like neuron-specific RNA binding protein 3; FDA: Food and Drug Administration; hb: habenula; hpt, hours post treatment; Map1lc3b: microtubule-associated protein 1 light chain 3 beta; nt: neural tube; ot, optic tectum; P/E: pepstatin A and E64d; PD: Parkinson disease; PMTs: photomultiplier tubes; PTU: 1-phenyl-2-thiourea; Ta: annealing temperature; Tel, telencephalon.
Collapse
Affiliation(s)
- Sataree Khuansuwan
- Department of Neurology, University of California at Los Angeles, Los Angeles, CA, USA
| | - Lisa M. Barnhill
- Department of Neurology, University of California at Los Angeles, Los Angeles, CA, USA
- Molecular Toxicology Program, University of California at Los Angeles, Los Angeles, CA, USA
| | - Sizhu Cheng
- UCLA Undergraduate Interdepartmental Program for Neuroscience, University of California at Los Angeles, Los Angeles, CA, USA
| | - Jeff M. Bronstein
- Department of Neurology, University of California at Los Angeles, Los Angeles, CA, USA
- Molecular Toxicology Program, University of California at Los Angeles, Los Angeles, CA, USA
| |
Collapse
|
11
|
Guzman JN, Ilijic E, Yang B, Sanchez-Padilla J, Wokosin D, Galtieri D, Kondapalli J, Schumacker PT, Surmeier DJ. Systemic isradipine treatment diminishes calcium-dependent mitochondrial oxidant stress. J Clin Invest 2018; 128:2266-2280. [PMID: 29708514 PMCID: PMC5983329 DOI: 10.1172/jci95898] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 03/13/2018] [Indexed: 01/04/2023] Open
Abstract
The ability of the Cav1 channel inhibitor isradipine to slow the loss of substantia nigra pars compacta (SNc) dopaminergic (DA) neurons and the progression of Parkinson's disease (PD) is being tested in a phase 3 human clinical trial. But it is unclear whether and how chronic isradipine treatment will benefit SNc DA neurons in vivo. To pursue this question, isradipine was given systemically to mice at doses that achieved low nanomolar concentrations in plasma, near those achieved in patients. This treatment diminished cytosolic Ca2+ oscillations in SNc DA neurons without altering autonomous spiking or expression of Ca2+ channels, an effect mimicked by selectively knocking down expression of Cav1.3 channel subunits. Treatment also lowered mitochondrial oxidant stress, reduced a high basal rate of mitophagy, and normalized mitochondrial mass - demonstrating that Cav1 channels drive mitochondrial oxidant stress and turnover in vivo. Thus, chronic isradipine treatment remodeled SNc DA neurons in a way that should not only diminish their vulnerability to mitochondrial challenges, but to autophagic stress as well.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Paul T. Schumacker
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | | |
Collapse
|
12
|
Ortner NJ, Bock G, Dougalis A, Kharitonova M, Duda J, Hess S, Tuluc P, Pomberger T, Stefanova N, Pitterl F, Ciossek T, Oberacher H, Draheim HJ, Kloppenburg P, Liss B, Striessnig J. Lower Affinity of Isradipine for L-Type Ca 2+ Channels during Substantia Nigra Dopamine Neuron-Like Activity: Implications for Neuroprotection in Parkinson's Disease. J Neurosci 2017; 37:6761-6777. [PMID: 28592699 PMCID: PMC6596555 DOI: 10.1523/jneurosci.2946-16.2017] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 05/08/2017] [Accepted: 05/13/2017] [Indexed: 12/21/2022] Open
Abstract
Ca2+-influx through L-type Ca2+-channels (LTCCs) is associated with activity-related stressful oscillations of Ca2+ levels within dopaminergic (DA) neurons in the substantia nigra (SN), which may contribute to their selective degeneration in Parkinson's disease (PD). LTCC blockers were neuroprotective in mouse neurotoxin models of PD, and isradipine is currently undergoing testing in a phase III clinical trial in early PD. We report no evidence for neuroprotection by in vivo pretreatment with therapeutically relevant isradipine plasma levels, or Cav1.3 LTCC deficiency in 6-OHDA-treated male mice. To explain this finding, we investigated the pharmacological properties of human LTCCs during SN DA-like and arterial smooth muscle (aSM)-like activity patterns using whole-cell patch-clamp recordings in HEK293 cells (Cav1.2 α1-subunit, long and short Cav1.3 α1-subunit splice variants; β3/α2δ1). During SN DA-like pacemaking, only Cav1.3 variants conducted Ca2+ current (ICa) at subthreshold potentials between action potentials. SN DA-like burst activity increased integrated ICa during (Cav1.2 plus Cav1.3) and after (Cav1.3) the burst. Isradipine inhibition was splice variant and isoform dependent, with a 5- to 11-fold lower sensitivity to Cav1.3 variants during SN DA-like pacemaking compared with Cav1.2 during aSM-like activity. Supratherapeutic isradipine concentrations reduced the pacemaker precision of adult mouse SN DA neurons but did not affect their somatic Ca2+ oscillations. Our data predict that Cav1.2 and Cav1.3 splice variants contribute differentially to Ca2+ load in SN DA neurons, with prominent Cav1.3-mediated ICa between action potentials and after bursts. The failure of therapeutically relevant isradipine levels to protect SN DA neurons can be explained by weaker state-dependent inhibition of SN DA LTCCs compared with aSM Cav1.2.SIGNIFICANCE STATEMENT The high vulnerability of dopamine (DA) neurons in the substantia nigra (SN) to neurodegenerative stressors causes Parkinson's disease (PD). Ca2+ influx through voltage-gated L-type Ca2+ channels (LTCCs), in particular Cav1.3, appears to contribute to this vulnerability, and the LTCC inhibitor isradipine is currently being tested as a neuroprotective agent for PD in a phase III clinical trial. However, in our study isradipine plasma concentrations approved for therapy were not neuroprotective in a PD mouse model. We provide an explanation for this observation by demonstrating that during SN DA-like neuronal activity LTCCs are less sensitive to isradipine than Cav1.2 LTCCs in resistance blood vessels (mediating dose-limiting vasodilating effects) and even at supratherapeutic concentrations isradipine fails to reduce somatic Ca2+ oscillations of SN DA neurons.
Collapse
Affiliation(s)
- Nadine J Ortner
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Gabriella Bock
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Antonios Dougalis
- Institute of Applied Physiology, University of Ulm, 89081 Ulm, Germany
| | - Maria Kharitonova
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Johanna Duda
- Institute of Applied Physiology, University of Ulm, 89081 Ulm, Germany
| | - Simon Hess
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Thomas Pomberger
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | | | - Florian Pitterl
- Institute of Legal Medicine and Core Facility Metabolomics, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Thomas Ciossek
- Boehringer Ingelheim Pharma GmbH & Co KG, CNS Research, 88400 Biberach an der Riss, Germany, and
| | - Herbert Oberacher
- Institute of Legal Medicine and Core Facility Metabolomics, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Henning J Draheim
- Boehringer Ingelheim Pharma GmbH & Co KG, CNS Research, 88400 Biberach an der Riss, Germany, and
| | - Peter Kloppenburg
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany
| | - Birgit Liss
- Institute of Applied Physiology, University of Ulm, 89081 Ulm, Germany
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria,
| |
Collapse
|
13
|
Lu ZJ, Pereverzev A, Liu HL, Weiergräber M, Henry M, Krieger A, Smyth N, Hescheler J, Schneider T. Arrhythmia in Isolated Prenatal Hearts after Ablation of the Ca v2.3 (α1E) Subunit of Voltage-gated Ca 2+ Channels. Cell Physiol Biochem 2010; 14:11-22. [PMID: 14976402 DOI: 10.1159/000076922] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2003] [Indexed: 11/19/2022] Open
Abstract
A voltage-gated calcium channel containing Cav2.3e (alpha1Ee) as the ion conducting pore has recently been detected in rat heart. Functional evidence for this Ca2+ channel to be involved in the regulation of heart beating, besides L- and T-type channels, was derived from murine embryos where the gene for Cav1.2 had been ablated. The remaining "L-type like" current component was not related to recombinant splice variants of Cav1.3 containing channels. As recombinant Cav2.3 channels from rat were reported to be weakly dihydropyridine sensitive, the spontaneous activity of the prenatal hearts from Cav2.3(-|-) mice was compared to that of Cav2.3(+|+) control animals to investigate if Cav2.3 could represent such a L-type like Ca(2+) channel. The spontaneous activity of murine embryonic hearts was recorded by using a multielectrode array. Between day 9.5 p.c. to 12.5 p.c., the beating frequency of isolated embryonic hearts from Cav2.3-deficient mice did not differ significantly from control mice but the coefficient of variation within individual episodes was more than four-fold increased in Cav2.3-deficient mice indicating arrhythmia. In isolated hearts from wild type mice, arrhythmia was induced by superfusion with a solution containing 200 nM SNX-482, a blocker of some R-type voltage gated Ca2+ channels, suggesting that R-type channels containing the splice variant Cav2.3e as ion conducting pore stabilize a more regular heart beat in prenatal mice.
Collapse
Affiliation(s)
- Zhong-Ju Lu
- Institute of Neurophysiology, Medical Faculty, University of Köln, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Banat M, Lüke M, Siapich SA, Hescheler J, Weiergräber M, Schneider T. The dihydropyridine isradipine inhibits the murine but not the bovine A-wave response of the electroretinogram. Acta Ophthalmol 2008; 86:676-82. [PMID: 18752519 DOI: 10.1111/j.1600-0420.2007.01126.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE In order to record light-evoked responses from photoreceptor cells and the higher neuronal retinal network, the isolated vertebrate retina represents a sensitive tool for basic research of retinal function and for testing the toxicity of ocular therapeutics. In the past, this in vitro technique was optimized for frog and bovine retina; it should be transferred now to the isolated murine retina because the model could allow for functional testing of genes involved in retinal signalling using wild-type and gene-inactivated mice. Thus, alterations in the electroretinogram (ERG) may reveal differences in retinal information processing because of the inactivation of a specific gene. METHODS We used a superfused vertebrate retina assay to test bovine and murine retina. RESULTS In order to evaluate the sensitivity of the ERG recording technique from the isolated murine retina, we first determined the light intensity response and the stability of the a-wave amplitude during ERG recording, which did not differ between the species. However, testing the dihydropyridine sensitivity of the a-wave, we found that the murine a-wave was highly sensitive towards racemic isradipine (8-25 nM) but the bovine retina a-wave was not. A similar species-dependent difference was observed for mibefradil (10 muM). CONCLUSION Murine and bovine retina differ with respect to transretinal signalling. At the level of photoreceptor cells, the ERG/a-wave is modulated by isradipine-sensitive voltage-gated Ca(2+) channels, which trigger feedback signalling to photoreceptors.
Collapse
Affiliation(s)
- Mohammed Banat
- Institute of Neurophysiology, University of Cologne, Germany
| | | | | | | | | | | |
Collapse
|
15
|
Abstract
In clonal beta-cell lines and islets from different species, a variety of calcium channels are coupled to glucose-stimulated insulin secretion. The aim of this study was to identify the voltage-gated calcium channels that control insulin secretion in insulinoma (INS)-1 832/13 cells. The mRNA level of Ca(V)1.2 exceeded that of Ca(V)1.3 and Ca(V)2.3 two-fold. Insulin secretion, which rose tenfold in response to 16.7 mM glucose, was completely abolished by 5 microM isradipine that blocks Ca(V)1.2 and Ca(V)1.3. Similarly, the increase in intracellular calcium in response to 15 mM glucose was decreased in the presence of 5 microM isradipine, and the frequency of calcium spikes was decreased to the level seen at 2.8 mM glucose. By contrast, inhibition of Ca(V)2.3 with 100 nM SNX-482 did not significantly affect insulin secretion or intracellular calcium. Using RNA interference, Ca(V)1.2 mRNA and protein levels were knocked down by approximately 65% and approximately 34% respectively, which reduced insulin secretion in response to 16.7 mM glucose by 50%. Similar reductions in calcium currents and cell capacitance were seen in standard whole-cell patch-clamp experiments. The remaining secretion of insulin could be reduced to the basal level by 5 microM isradipine. Calcium influx underlying this residual insulin secretion could result from persisting Ca(V)1.2 expression in transfected cells since knock-down of Ca(V)1.3 did not affect glucose-stimulated insulin secretion. In summary, our results suggest that Ca(V)1.2 is critical for insulin secretion in INS-1 832/13 cells.
Collapse
Affiliation(s)
- Marloes Dekker Nitert
- Molecular Metabolism Islet Cell Exocytosis, Department of Clinical Science, Clinical Research Center, SE-205 02 Malmö, Sweden Lund University Diabetes Center, Malmö, Sweden.
| | | | | | | | | |
Collapse
|
16
|
Abstract
Parkinson's disease is a common neurodegenerative disorder of unknown cause. There is no cure or proven strategy for slowing the progression of the disease. Although there are signs of pathology in many brain regions, the core symptoms of Parkinson's disease are attributable to the selective degeneration of dopaminergic neurons in the substantia nigra pars compacta. A potential clue to the vulnerability of these neurons is their increasing reliance on Ca(2+) channels to maintain autonomous activity with age. This reliance could pose a sustained metabolic stress on mitochondria, accelerating cellular ageing and death. The Ca(2+) channels underlying autonomous activity in dopaminergic neurons are closely related to the L-type channels found in the heart and smooth muscle. Systemic administration of isradipine, a dihydropyridine blocker of L-type channels, forces dopaminergic neurons in rodents to revert to a juvenile, Ca(2+)-independent mechanism to generate autonomous activity. More importantly, reversion confers protection against toxins that produce experimental parkinsonism, pointing to a potential neuroprotective strategy for Parkinson's disease with a drug class that has been used safely in human beings for decades. These studies also suggest that, although genetic and environmental factors can hasten its onset, Parkinson's disease stems from a distinctive neuronal design common to all human beings, making its appearance simply a matter of time.
Collapse
Affiliation(s)
- D James Surmeier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
| |
Collapse
|
17
|
Zhang Q, Bengtsson M, Partridge C, Salehi A, Braun M, Cox R, Eliasson L, Johnson PRV, Renström E, Schneider T, Berggren PO, Göpel S, Ashcroft FM, Rorsman P. R-type Ca(2+)-channel-evoked CICR regulates glucose-induced somatostatin secretion. Nat Cell Biol 2007; 9:453-60. [PMID: 17369816 DOI: 10.1038/ncb1563] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Accepted: 02/27/2007] [Indexed: 11/08/2022]
Abstract
Pancreatic islets have a central role in blood glucose homeostasis. In addition to insulin-producing beta-cells and glucagon-secreting alpha-cells, the islets contain somatostatin-releasing delta-cells. Somatostatin is a powerful inhibitor of insulin and glucagon secretion. It is normally secreted in response to glucose and there is evidence suggesting its release becomes perturbed in diabetes. Little is known about the control of somatostatin release. Closure of ATP-regulated K(+)-channels (K(ATP)-channels) and a depolarization-evoked increase in cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)) have been proposed to be essential. Here, we report that somatostatin release evoked by high glucose (>or=10 mM) is unaffected by the K(ATP)-channel activator diazoxide and proceeds normally in K(ATP)-channel-deficient islets. Glucose-induced somatostatin secretion is instead primarily dependent on Ca(2+)-induced Ca(2+)-release (CICR). This constitutes a novel mechanism for K(ATP)-channel-independent metabolic control of pancreatic hormone secretion.
Collapse
Affiliation(s)
- Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Pyregov AV, Aliautdin RN, Petrov VE, Pivovarova GM, Siluianova EV, Gur'ianov VA. [Experimental investigations of the analgesic activity of fentanyl and the non-opiodal agents -clonidine and isradipine, and protease inhibitors]. Anesteziol Reanimatol 2007:60-3. [PMID: 17564006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The analgesic activity of clonidine, isradipine, antagosane (aprotinine), transamine, and their combinations with fentanyl in subanalgesic doses was experimentally studied on mice, by using the tail-flick test. Analgesic activity was found in clonidine, antagosane, and transamine. A combination of fentanyl used in subanalgesic doses and clonidine, isradipine, antagosane, or transamine had supertotal analgesic activity. The findings serve as a basis for effectively making up a component of analgesia during anesthetic support at surgery made in patients with baseline sympathicotonia, ischemia/reperfusion syndrome, and a systemic inflammatory reaction.
Collapse
|
19
|
Lopes GS, Smaili SS, Neto AC, Vladimirova I, Jurkiewicz A, Jurkiewicz NH. Aging-Induced Decrease of Cholinergic Response and Calcium Sensitivity on Rat Jejunum Contractions. J Gerontol A Biol Sci Med Sci 2007; 62:264-70. [PMID: 17389723 DOI: 10.1093/gerona/62.3.264] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The role of aging on contraction or relaxation through muscarinic or alpha-adrenergic receptors, respectively, was studied in isolated rat jejunum. Furthermore, the influence of extracellular calcium was analyzed, through functional and radioligand binding assays. The rank order of potency for selective muscarinic antagonists for M(1), M(2), and M(3) receptor subtypes, measured from affinity (pA(2)) values, was p-fluorohexahydrosiladifenidol (pFHHSiD) (M(3)) > pirenzepine (M(1)) > methoctramine (M(2)), indicating a predominance of M(3) subtype. This order was unchanged with age. Contractions by muscarinic agonist methacholine (MCh) were diminished in aged rats, resulting in lower apparent affinity (pD(2)) values, compared with adult controls. A larger decrease of MCh contractions occurred in aged rats after Ca(2+) withdrawal or after the calcium channel blocker isradipine. Changes were not detected for relaxation by adrenergic agonists. In conclusion, aging caused a decrease of MCh potency, which is probably related to the reduction of calcium sensitivity in jejunum.
Collapse
Affiliation(s)
- Guiomar Silva Lopes
- Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil.
| | | | | | | | | | | |
Collapse
|
20
|
Abstract
Activation of large conductance Ca(2+)-activated potassium (BK) channels hastens action potential repolarisation and generates the fast afterhyperpolarisation in hippocampal pyramidal neurons. A rapid coupling of Ca(2+) entry with BK channel activation is necessary for this to occur, which might result from an identified coupling of Ca(2+) entry through N-type Ca(2+) channels to BK channel activation. This selective coupling was extremely rapid and resistant to intracellular BAPTA, suggesting that the two channel types are close. Using reciprocal co-immunoprecipitation, we found that N-type channels were more abundantly associated with BK channels than L-type channels (Ca(V)1.2) in rat brain. Expression of only the pore-forming alpha-subunits of the N-type (Ca(V)2.2) and BK (Slo(27)) channels in a non-neuronal cell-line gave robust macroscopic currents and reproduced the interaction. Co-expression of Ca(V)2.2/Ca(V)beta(3) subunits with Slo(27) channels revealed rapid functional coupling. By contrast, extremely rare examples of rapid functional coupling were observed with co-expression of Ca(V)1.2/Ca(V)beta(3) and Slo(27) channels. Action potential repolarisation in hippocampal pyramidal neurons was slowed by the N-type channel blocker omega-conotoxin GVIA, but not by the L-type channel blocker isradipine. These data showed that selective functional coupling between N-type Ca(2+) and BK channels provided rapid activation of BK channels in central neurons.
Collapse
Affiliation(s)
- David J Loane
- Department of Pharmacology and MRC Centre for Synaptic Plasticity, University of Bristol, Bristol, BS8 1TD, UK
| | | | | |
Collapse
|
21
|
Abstract
This study examines the molecular basis for the T-type and L-type Ca(2+) currents in canine Purkinje cells. The I(CaT) in Purkinje cells was completely suppressed by 200 nM kurtoxin, a specific blocker of both Ca(v)3.1 and Ca(v)3.2 channels. Since only Ca(v)3.2 mRNA is expressed at high levels in Purkinje fibres, being approximately 100-fold more abundant than either Ca(v)3.1 or Ca(v)3.3 mRNAs, it is concluded that the Ca(v)3.2 gene encodes the bulk of the T-type Ca(2+) channels in canine Purkinje cells. This conclusion is consistent with the sensitivity of the current to blockade by Ni(2+) ions (K(D) = 32 microM). For L-type channels, Ca(v)1.2 mRNA was most abundant in Purkinje fibres but a significant level of Ca(v)1.3 mRNA expression was also found. A comparison of the sensitivity to blockade by isradipine of the L-type currents in Purkinje cells and ventricular epicardial myocytes, which only express Ca(v)1.2, suggests that the Ca(v)1.3 channels make, at most, a minor contribution to the L-type current in canine Purkinje cells.
Collapse
Affiliation(s)
- Barbara Rosati
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA.
| | | | | | | | | |
Collapse
|
22
|
Abstract
The impact of modest but prolonged (3 h) exposure to high physiological glucose concentrations and hyperkalemia on the insulin secretory and phospholipase C (PLC) responses of rat pancreatic islets was determined. In acute studies, glucose (5-20 mM) caused a dose-dependent increase in secretion with maximal release rates 25-fold above basal secretion. When measured after 3 h of exposure to 5-10 mM glucose, subsequent stimulation of islets with 10-20 mM glucose during a dynamic perifusion resulted in dose-dependent decrements in secretion and PLC activation. Acute hyperkalemia (15-30 mM) stimulated calcium-dependent increases in both insulin secretion and PLC activation; however, prolonged hyperkalemia resulted in a biochemical and secretory lesion similar to that induced by sustained modest hyperglycemia. Glucose- (8 mM) desensitized islets retained significant sensitivity to stimulation by either carbachol or glucagon-like peptide-1. These findings emphasize the vulnerability of the beta-cell to even moderate sustained hyperglycemia and provide a biochemical rationale for achieving tight glucose control in diabetic patients. They also suggest that PLC activation plays a critically important role in the physiological regulation of glucose-induced secretion and in the desensitization of release that follows chronic hyperglycemia or hyperkalemia.
Collapse
Affiliation(s)
- Hanae Yamazaki
- Yale University School of Nursing, New Haven, CT 06536-0740, USA
| | | | | |
Collapse
|
23
|
Peterson BZ, Catterall WA. Allosteric interactions required for high-affinity binding of dihydropyridine antagonists to Ca(V)1.1 Channels are modulated by calcium in the pore. Mol Pharmacol 2006; 70:667-75. [PMID: 16675661 DOI: 10.1124/mol.105.020644] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dihydropyridines (DHPs) are an important class of drugs, used extensively in the treatment of angina pectoris, hypertension, and arrhythmia. The molecular mechanism by which DHPs modulate Ca(2+) channel function is not known in detail. We have found that DHP binding is allosterically coupled to Ca(2+) binding to the selectivity filter of the skeletal muscle Ca(2+) channel Ca(V)1.1, which initiates excitation-contraction coupling and conducts L-type Ca(2+) currents. Increasing Ca(2+) concentrations from approximately 10 nM to 1 mM causes the DHP receptor site to shift from a low-affinity state to a high-affinity state with an EC(50) for Ca(2+) of 300 nM. Substituting each of the four negatively charged glutamate residues that form the ion selectivity filter with neutral glutamine or positively charged lysine residues results in mutant channels whose DHP binding affinities are decreased up to 10-fold and are up to 150-fold less sensitive to Ca(2+) than wild-type channels. Analysis of mutations of amino acid residues adjacent to the selectivity filter led to identification of Phe-1013 and Tyr-1021, whose mutation causes substantial changes in DHP binding. Thermo-dynamic mutant cycle analysis of these mutants demonstrates that Phe-1013 and Tyr-1021 are energetically coupled when a single Ca(2+) ion is bound to the channel pore. We propose that DHP binding stabilizes a nonconducting state containing a single Ca(2+) ion in the pore through which Phe-1013 and Tyr-1021 are energetically coupled. The selectivity filter in this energetically coupled high-affinity state is blocked by bound Ca(2+), which is responsible for the high-affinity inhibition of Ca(2+) channels by DHP antagonists.
Collapse
Affiliation(s)
- Blaise Z Peterson
- Cellular and Molecular Physiology, H166, Penn State Milton S. Hershey Medical Center, College of Medicine, 500 University Dr., Room C6603, P.O. Box 850, Hershey, PA 17033-0850, USA.
| | | |
Collapse
|
24
|
Hattori T, Wang PL. Calcium antagonist isradipine-induced calcium influx through nonselective cation channels in human gingival fibroblasts. Eur J Med Res 2006; 11:93-6. [PMID: 16751108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023] Open
Abstract
Isradipine raises the cytosolic Ca2+ concentration ([Ca2+]i) in human gingival fibroblasts by enhancing Ca2+ influx through the plasma membrane. To research the pathways through which Ca2+ enters the cells, we examined the interactive effects of isradipine and blockers or enhancers of nonselective cation channels (NSCCs) and Na+/Ca2+ exchangers (NCXs). Normal human gingival fibroblast Gin-1 cells were used. The [Ca2+]i was measured with the Ca2+-sensitive fluorescent dye fura-2/AM. Changes in the fluorescence intensity of fura-2 in the cells were recorded with a video-imaging analysis system. Ca2+ antagonists (nifedipine, verapamil, and diltiazem in the concentration range of 1 to 20 microM) other than isradipine also raised the [Ca2+]i. All of the NSCC inhibitors (SK&F 96365, GdCl3, HgCl2 and flufenamic acid), but none of the NCX inhibitors (KB-R 7943 and benzamil), significantly decreased the [Ca2+]i raised by isradipine (3 microM). Neither the Na+ ionophore monensin nor Na+/K+ ATPase inhibitor ouabain had any significant effect on the isradipine-induced [Ca2+]i rise. Taken together, our data indicate that Ca2+ entry through the NSCCs is involved in the isradipine-induced [Ca2+]i rise. The results obtained here play an important role in the development of drugs for etiologic therapy of gingival overgrowth.
Collapse
Affiliation(s)
- T Hattori
- Department of Dental Pharmacology, Matsumoto Dental University, Shiojiri, Japan.
| | | |
Collapse
|
25
|
Hattori T, Ara T, Wang P. Participation of tyrosine kinase and phospholipase Cgamma in isradipine-induced proliferation of cultured human gingival fibroblasts. Eur J Med Res 2005; 10:543-6. [PMID: 16356872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023] Open
Abstract
Some kinds of drugs such as calcium (Ca(2+)) channel antagonists, antiepileptics and immunosuppressants cause gingival overgrowth as a side effect, the mechanism of which is still unclear. We have examined the effects of isradipine, one of the dihydropyridine-derivative Ca(2+) channel antagonists, on cultured human gingival fibroblast Gin-1 cells. In the present study, to elucidate the mechanism by which isradipine causes gingival overgrowth, we examined whether tyrosine kinase (TK) and phopholipase Cgamma (PLCgamma) are involved in the isradipine-induced proliferation of gingival fibroblasts. Herbimycin A (1 microM) remarkably inhibited the isradipime (10 microM)-induced proliferation. Both U73122 (5 microM), a PLCgamma inhibitor, and xestospongin C (5 microM), an antagonist of a receptor of inositol 1,4,5-trisphosphate in Ca(2+) stores, significantly reduced the [Ca(2+)]i raised by isradipine (10 microM). Thus, the findings obtained here indicate that TK and PLCgamma are closely involved in the isradipine-induced [Ca(2+)]i rise to elicit gingival overgrowth.
Collapse
Affiliation(s)
- Toshimi Hattori
- Department of Dental Pharmacology, Matsumoto Dental University, Shiojiri, Japan.
| | | | | |
Collapse
|
26
|
Johnson BA, Roache JD, Ait-Daoud N, Wallace CL, Wells LT, Wang Y, Dawes MA. Effects of isradipine on cocaine-induced changes in cognitive performance in recently abstinent cocaine-dependent individuals. Int J Neuropsychopharmacol 2005; 8:549-56. [PMID: 15916717 DOI: 10.1017/s1461145705005511] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Revised: 02/24/2005] [Accepted: 03/02/2005] [Indexed: 11/07/2022] Open
Abstract
Recently abstinent cocaine-dependent individuals, compared with healthy controls, appear more likely to exhibit deficits in cognitive performance and attention. Individuals with such cognitive deficits might be less able to avail themselves of rehabilitative or relapse-prevention efforts. Pharmacotherapy that reduces the impairment in cognitive performance among cocaine-dependent individuals would be a useful clinical tool. Preclinical and human studies suggest that the dihydropyridine-class calcium-channel antagonist, isradipine, can enhance neurocognitive function in some neuropsychiatric disorders. Isradipine, presumably by increasing cerebral blood flow and its actions at various neurotransmitter systems, might, therefore, ameliorate the impairment in cognitive performance and attention seen in cocaine addicts and enhance the expected modest improvement in performance during acute cocaine-taking in these same individuals. Among 12 male and female cocaine-dependent individuals, we examined the effects of low and high doses of intravenous cocaine (0, 0.325, and 0.650 mg/kg) on cognitive performance and attention in both the presence and absence of isradipine (0 or 30 mg sustained release each evening prior to testing, plus 0 or 15 mg immediate release each morning 2 h before the cocaine or placebo cocaine infusion and on the day of testing). Intravenous cocaine produced a modest increase in cognitive performance and attention. Isradipine, both with and without cocaine, had no effect on these same parameters. Hence, cocaine-taking by cocaine-dependent individuals produces little improvement in cognitive performance and attention in either the presence or absence of isradipine.
Collapse
Affiliation(s)
- Bankole A Johnson
- Department of Psychiatric Medicine, University of Virginia, Charlottesville, VA 22908-0623, USA.
| | | | | | | | | | | | | |
Collapse
|
27
|
Randrianarivelojosia M, Jambou R. Isradipine--a calcium channel blocker--does not potentiate chloroquine antiplasmodial activity against Plasmodium falciparum. Parasite 2005; 12:187-9. [PMID: 15991834 DOI: 10.1051/parasite/2005122187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Culturing fresh clinical isolates of P. falciparum and using the isotopic method, we tested separately chloroquine and isradipine--a calcium channel blocker--, and also the combination isradipine plus chloroquine. Tested wild isolates were chloroquine-sensitive. With regard to the combination isradipine/chloroquine, the isobolograms obtained indicate that isradipine antagonises chloroquine antiplasmodial activity. Taking into account these findings, we discuss the issues related to the calcium channel blocker molecules.
Collapse
|
28
|
Yin X, Polidano E, Faverdin C, Marche P. Role of L-type calcium channel blocking in epidermal growth factor receptor-independent activation of extracellular signal regulated kinase 1/2. J Hypertens 2005; 23:337-50. [PMID: 15662222 DOI: 10.1097/00004872-200502000-00016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Vascular smooth muscle cell (VSMC) differentiation, growth and survival, key events in the development of cardiovascular diseases, are under the control of signaling enzymes including extracellular signal regulated kinase 1/2 (ERK 1/2), Akt and epidermal growth factor receptor (EGFR) activation. EGFR trans-activation is known to mediate thrombin- or angiotensin II (AII)-stimulated ERK 1/2 activation. However, our laboratory has demonstrated, in thrombin-stimulated VSMC, that the prevention of intracellular Ca2+ elevation ([Ca2+]i) by BAPTA-AM pretreatment unveiled EGFR-independent ERK 1/2 activation. Since calcium channel blockers (CCBs) also impair agonist-induced [Ca2+]i elevation, we investigated whether EGFR-independent ERK 1/2 activation could occur in VSMCs treated by CCBs such as amlodipine, isradipine and verapamil, and examined the possible role of Akt. METHODS Cultured VSMCs were pretreated or not with CCBs and with various inhibitors of the signaling pathways under study, prior to stimulation by thrombin or AII, and the phosphorylation/activation status of EGFR, Akt and ERK 1/2 was determined by Western blotting using phospho-specific antibodies. RESULTS AND CONCLUSION Unlike BAPTA, CCBs did not impair stimulus-induced EGFR trans-activation, hence ERK1/2 phosphorylation. However, when EGFR kinase was inhibited, CCBs and BAPTA dose-dependently protected stimulus-induced ERK1/2 phosphorylation. The effect of amlodipine could not be mimicked by its R+ enantiomer, which is devoid of CCB activity, suggesting that the effects of CCBs were accounted for by their L-type Ca2+ channel-blocking property. Altogether, our results indicated that in G-protein-coupled receptor (GPCR)-stimulated VSMCs, the prevention of [Ca2+]i elevation by CCBs unmasked an EGFR kinase-independent phosphorylation of ERK 1/2. Since EGFR kinase inhibitors are supposed to be efficient in the treatment of some cancers, such a mechanism might be clinically relevant in hypertensive patients with cancer.
Collapse
MESH Headings
- Amlodipine/pharmacology
- Angiotensin II/pharmacology
- Animals
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/drug effects
- Cells, Cultured
- Chelating Agents/pharmacology
- Dose-Response Relationship, Drug
- Egtazic Acid/analogs & derivatives
- Egtazic Acid/pharmacology
- Enzyme Activation/drug effects
- ErbB Receptors/metabolism
- Isradipine/pharmacology
- MAP Kinase Signaling System/drug effects
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Protein Serine-Threonine Kinases/metabolism
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-akt
- Rats
- Rats, Wistar
- Thrombin/pharmacology
- Verapamil/pharmacology
Collapse
Affiliation(s)
- Xing Yin
- Centre National de la Recherche Scientifique UMR 7131, Université Pierre et Marie Curie, Hôpital Broussais, 75014, Paris, France
| | | | | | | |
Collapse
|
29
|
Arun KHS, Kaul CL, Ramarao P. AT receptors and L-type calcium channels: functional coupling in supersensitivity to angiotensin II in diabetic rats. Cardiovasc Res 2005; 65:374-86. [PMID: 15639476 DOI: 10.1016/j.cardiores.2004.10.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2004] [Revised: 09/20/2004] [Accepted: 10/07/2004] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE The study was designed to investigate the role of calcium channels in enhanced angiotensin II (Ang II)-induced contraction in thoracic aortic rings from diabetic rats. METHODS Ang II-induced isometric tension was studied in thoracic aortic rings isolated from control or streptozotocin-induced (8 weeks) diabetic rats. Saturation binding studies at AT1 receptors and L-type calcium channels were performed using [3H] Ang II and [3H] PN200110, respectively. Ang II-induced calcium influx was studied in fura-2-loaded single vascular smooth muscle cells isolated from thoracic aorta of control and diabetic rats. RESULTS Ang II did not induce contraction in calcium-free Krebs. In the presence of extracellular calcium, increased Emax (mg/mm2) and pD2 to Ang II was observed in aortic rings from diabetic (795.54+/-38.19; 8.27+/-0.12) compared to control (230.09+/-25.45; 7.68+/-0.22) rats, respectively. Nimodipine but not verapamil or diltiazem dose-dependently blocked the Ang II-induced contractions in a noncompetitive manner and its -log IC50 was significantly lower in aortic rings from diabetic (8.81+/-0.10) compared to control (9.34+/-0.11) rats. The Ang II-induced increase in intracellular calcium levels was significantly enhanced (2.5-fold) in vascular smooth muscle cells from diabetic rats. AT1 receptor saturation binding with [3H] Ang II revealed a significantly higher affinity (nM) and Bmax (pmol/mg protein) in aortic vascular membrane preparation from diabetic (0.31+/-0.04; 64.18+/-2.4) compared to control (0.52+/-0.02; 47.81+/-2.8) rats, respectively, while L-type calcium channel saturation binding with [3H] PN200110 showed a higher affinity (nM) with no change in the Bmax (fmol/mg protein) in diabetic (0.74+/-0.08; 4.52+/-0.40) compared to control (1.49+/-0.32; 5.43+/-0.60) aortic membranes, respectively. CONCLUSIONS Our results suggest that Ang II-induced contraction is dependent on extracellular calcium, and enhanced functional coupling of AT1 receptors and DHP-sensitive L-type calcium channels results in supersensitivity to Ang II in thoracic aorta isolated from diabetic rats.
Collapse
MESH Headings
- Angiotensin II/pharmacology
- Animals
- Aorta, Thoracic
- Calcium/analysis
- Calcium/metabolism
- Calcium/pharmacology
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/metabolism
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Depression, Chemical
- Diabetes Mellitus, Experimental/metabolism
- Dose-Response Relationship, Drug
- In Vitro Techniques
- Isradipine/pharmacology
- Male
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Nimodipine/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptor, Angiotensin, Type 1/metabolism
Collapse
Affiliation(s)
- K H S Arun
- Cardiovascular and Receptorology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67, S.A.S. Nagar, Punjab-160062, India
| | | | | |
Collapse
|
30
|
Abstract
We performed experiments to examine whether isradipine (Isr), a calcium antagonist, would raise the intracellular calcium concentration ([Ca2+]i) in Gin-1 cells and, if so, to elucidate the mechanism of the [Ca2+]i rise. Gin-1 cells, which are human normal gingival fibroblasts were used as the material. The [Ca2+]i was measured with the Ca2+-sensitive fluorescent dye fura-2/AM. Changes in the fluorescence intensity of fura-2 in the cells were recorded with a video-imaging analysis system. Isr concentration-dependently raised the [Ca2+]i. A Ca2+-free saline significantly inhibited the Isr-induced [Ca2+]i rise. Whereas Isr in Ca2+-containing solution weakly raised the [Ca2+]i by pretreatment with thapsigargin, an inhibitor of Ca2+ release from Ca2+ stores, the Ca2+-free saline plus thapsigargin completely depressed the Isr-induced [Ca2+]i rise. The same response was observed in the case of pretreatment with cyclopiazonic acid (1 microM), another inhibitor of Ca2+ release from the Ca2+ stores. Isr raises the [Ca2+]i in Gin-1 cells and that the Isr-induced [Ca2+]i rise is ascribable to both the Ca2+ influx through the plasma membrane and Ca2+ release from the intracellular Ca2+ store.
Collapse
Affiliation(s)
- Toshimi Hattori
- Department of Dental Pharmacology, Matsumoto Dental University, Shiojiri 399-0781, Japan.
| | | |
Collapse
|
31
|
Johnson BA, Javors MA, Lam YWF, Wells LT, Tiouririne M, Roache JD, Ait-Daoud N, Lawson K. Kinetic and cardiovascular comparison of immediate-release isradipine and sustained-release isradipine among non-treatment-seeking, cocaine-dependent individuals. Prog Neuropsychopharmacol Biol Psychiatry 2005; 29:15-20. [PMID: 15610940 DOI: 10.1016/j.pnpbp.2004.08.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/27/2004] [Indexed: 11/17/2022]
Abstract
The authors sought to determine whether sustained-release (SR) isradipine provided comparable systemic availability to that of immediate-release (IR) isradipine in non-treatment-seeking, cocaine-dependent individuals. This information could be used to design a rational dosage regimen for additional isradipine clinical trials in the treatment of stimulant dependence and related neurovascular disorders. Eight male volunteers who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for cocaine dependence participated in a randomized, double-blind, crossover study. Subjects received a 15-mg dose of an IR isradipine formulation and a 30-mg dose of an SR isradipine formulation, separated by a 2-day interval. Vital signs and blood sampling for isradipine serum levels were performed before and at 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 8, 10, 12, and 24 h after each isradipine dose administration. Neither the 15-mg dose of IR isradipine nor the 30-mg dose of SR isradipine produced significant adverse effects on cardiovascular parameters, but the IR formulation was more likely to produce marked short-term decreases in pressor response. Significant intersubject variability in serum concentrations and pharmacokinetic parameters occurred for both formulations. The relative bioavailability of the SR formulation was 55.5% of that of the IR formulation. Both formulations cumulatively may deliver about the same amount of drug, but IR isradipine achieves a higher peak concentration than SR isradipine. The more favorable cardiovascular profile of SR isradipine would, however, make it more appropriate as an investigational medication for the treatment of stimulant dependence and related neurovascular disorders.
Collapse
Affiliation(s)
- Bankole A Johnson
- South Texas Addiction Research and Technology Center, Department of Psychiatry, The University of Texas Health Science Center at San Antonio, 3939 Medical Drive, Suite 100, San Antonio, TX 78229-3900, USA.
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Huber IG, Wappl-Kornherr E, Sinnegger-Brauns MJ, Hoda JC, Walter-Bastl D, Striessnig J. Opposite Effects of a Single IIIS5 Mutation on Phenylalkylamine and Dihydropyridine Interaction with L-type Ca2+ Channels. J Biol Chem 2004; 279:55211-7. [PMID: 15504730 DOI: 10.1074/jbc.m409008200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Replacement of L-type Ca(2+) channel alpha(1) subunit residue Thr-1066 in segment IIIS5 by a tyrosine residue conserved in the corresponding positions of non-L-type Ca(2+) channels eliminates high dihydropyridine sensitivity through a steric mechanism. To determine the effects of this mutation on phenylalkylamine interaction, we exploited the availability of Ca(v)1.2DHP(-/-) mice containing the T1066Y mutation. In contrast to dihydropyridines, increased protein-dependent binding of the phenylalkylamine (-)-[(3)H]devapamil occurred to Ca(v)1.2DHP(-/-) mouse brain microsomes. This effect could be attributed to an at least 2-fold increase in affinity as determined by saturation analysis and binding inhibition experiments. The latter also revealed a higher affinity for (-)-verapamil but not for (-)-gallopamil. The mutation caused a pronounced slowing of (-)-[(3)H]devapamil dissociation, indicating a stabilization of the drug-channel complex. The increased affinity of mutant channels was also evident in functional studies after heterologous expression of wild type and T1066Y channels in Xenopus laevis oocytes. 100 mum (-)-verapamil inhibited a significantly larger fraction of Ba(2+) inward current through mutant than through WT channels. Our results provide evidence that phenylalkylamines also interact with the IIIS5 helix and that the geometry of the IIIS5 helix affects the access and/or binding of different chemical classes of Ca(2+) channel blockers to their overlapping binding domains. Mutation of Thr-1066 to a non-L-type tyrosine residue can be exploited to differentially affect phenylalkylamine and dihydropyridine binding to L-type Ca(2+) channels.
Collapse
Affiliation(s)
- Irene G Huber
- Abteilung Pharmakologie und Toxikologie, Institut für Pharmazie, Universität Innsbruck, Peter-Mayrstrasse 1/I, A-6020 Innsbruck, Austria
| | | | | | | | | | | |
Collapse
|
33
|
Olofsson CS, Salehi A, Göpel SO, Holm C, Rorsman P. Palmitate stimulation of glucagon secretion in mouse pancreatic alpha-cells results from activation of L-type calcium channels and elevation of cytoplasmic calcium. Diabetes 2004; 53:2836-43. [PMID: 15504963 DOI: 10.2337/diabetes.53.11.2836] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We have investigated the short-term effects of the saturated free fatty acid (FFA) palmitate on pancreatic alpha-cells. Palmitate (0.5 or 1 mmol/l bound to fatty acid-free albumin) stimulated glucagon secretion from intact mouse islets 1.5- to 2-fold when added in the presence of 1-15 mmol/l glucose. Palmitate remained stimulatory in islets depolarized with 30 mmol/l extracellular K(+) or exposed to forskolin, but it did not remain stimulatory after treatment with isradipine or triacsin C. The stimulatory action of palmitate on secretion correlated with a 3.5-fold elevation of intracellular free Ca(2+) when applied in the presence of 15 mmol/l glucose, a 40% stimulation of exocytosis (measured as increases in cell capacitance), and a 25% increase in whole-cell Ca(2+) current. The latter effect was abolished by isradipine, suggesting that palmitate selectively modulates l-type Ca(2+) channels. The effect of palmitate on exocytosis was not mediated by palmitoyl-CoA, and intracellular application of this FFA metabolite decreased rather than enhanced Ca(2+)-induced exocytosis. The stimulatory effects of palmitate on glucagon secretion were paralleled by a approximately 50% inhibition of somatostatin release. We conclude that palmitate increases alpha-cell exocytosis principally by enhanced Ca(2+) entry via l-type Ca(2+) channels and, possibly, relief from paracrine inhibition by somatostatin released by neighboring delta-cells.
Collapse
|
34
|
Gursoy S, Kaya T, Kunt N, Karadas B, Bagcivan I, Kafali H. Interactive effect of sevoflurane with isradipine or indomethacin on spontaneous contractile activity of isolated pregnant rat myometrium. Int J Obstet Anesth 2004; 13:234-8. [PMID: 15477052 DOI: 10.1016/j.ijoa.2004.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2004] [Indexed: 11/26/2022]
Abstract
Volatile anesthetics, calcium antagonists and non-steroidal anti-inflammatory drugs inhibit contractile activity of myometrial smooth muscle. The aim of this study was to investigate the interactive effect of sevoflurane with isradipine or indomethacin on spontaneous contractile activity of myometrial strips isolated from pregnant rats. The myometrial strips were excised from rats (250-300 g) at 19-21 days of gestation and mounted in tissue baths for recording of isometric tension. Sevoflurane (0.5 to 3 MAC) inhibited the amplitude and frequency of spontaneous myometrial contractions in a concentration-dependent manner (P<0.05). Sevoflurane responses were repeated in the presence of isradipine (a dihydropyridine-type calcium channel blocker) and indomethacin (a non-selective cyclooxygenase (COX) inhibitor). Pretreatment with isradipine (10(-6) M) or indomethacin (10(-7) M), concentrations that themselves had no effect on spontaneous contractility, significantly increased the inhibitor responses to sevoflurane on amplitude and frequency of myometrial contractions, beginning at 1 MAC (P<0.05). Blockade of calcium channels in myometrial smooth muscle may increase the inhibitor effect of sevoflurane. Further work is needed to determine the cellular mechanism(s) of this interaction.
Collapse
Affiliation(s)
- S Gursoy
- Department of Anesthesiology, Cumhuriyet University School of Medicine, Sivas, Turkey
| | | | | | | | | | | |
Collapse
|
35
|
Hattori T, Hirai K, Wang P, Fujimura S. Proliferation of cultured human gingival fibroblasts caused by isradipine, a dihydropyridine-derivative calcium antagonist. Eur J Med Res 2004; 9:313-5. [PMID: 15257873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
As it was reported earlier that isradipine, a Ca superset 2+ antagonist of dihydropyridine derivative class, caused regression of nifedipine-induced hyperplasia of human gingiva, experiments were performed to examine whether or not isradipine would solely inhibit the proliferation of cultured gingival fibroblasts. Normal human gingival fibroblast Gin-1 cells were used to test the impact of this medication. Fibroblast proliferation in the presence of isradipine (10 microM) was examined by using the reagent water-soluble tetrazolium-1 (WST-1). The level of basic fibroblast growth factor (bFGF) in the cell-free supernatant of each well was determined by using an enzyme-linked immunosorvent assay (ELISA) kit. The production of type I collagen was assayed by ELISA. Isradipine significantly enhanced the cell proliferation from the second day of the culture period. Also, isradipine raised the level of bFGF in the culture medium. The same concentration, also significantly enhanced the production of type I collagen. In conclusion, we were able to prove that isradipine causes the proliferation of cultured gingival fibroblasts as well as other dihydropyridine-derivative Ca superset 2+ antagonists do. In order to prevent the gingival overgrowth, it is advisable to be very careful in the use of isradipine as a therapy for hypertension and other indications.
Collapse
Affiliation(s)
- T Hattori
- Department of Dental Pharmacology, Matsumoto Dental University, Shiojiri 399-0781, Japan.
| | | | | | | |
Collapse
|
36
|
Wegener JW, Schulla V, Lee TS, Koller A, Feil S, Feil R, Kleppisch T, Klugbauer N, Moosmang S, Welling A, Hofmann F. An essential role of Cav1.2 L-type calcium channel for urinary bladder function. FASEB J 2004; 18:1159-61. [PMID: 15132976 DOI: 10.1096/fj.04-1516fje] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mice deficient in the smooth muscle Cav1.2 calcium channel (SMACKO, smooth muscle alpha1c-subunit calcium channel knockout) have a severely reduced micturition and an increased bladder mass. L-type calcium current, protein, and spontaneous contractile activity were absent in the bladder of SMACKO mice. K+ and carbachol (CCh)-induced contractions were reduced to 10-fold in detrusor muscles from SMACKO mice. The dihydropyridine isradipine inhibited K+- and CCh-induced contractions of muscles from CTR but had no effect in muscles from SMACKO mice. CCh-induced contraction was blocked by removing extracellular Ca2+ but was unaffected by the PLC inhibitor U73122 or depletion of intracellular Ca2+ stores by thapsigargin. In muscles from CTR and SMACKO mice, CCh-induced contraction was partially inhibited by the Rho-kinase inhibitor Y27632. These results show that the Cav1.2 Ca2+ channel is essential for normal bladder function. The Rho-kinase and Ca2+-release pathways cannot compensate the lack of the L-type Ca2+ channel.
Collapse
Affiliation(s)
- Jörg W Wegener
- Institut für Pharmakologie und Toxikologie, Technische Universität München, Biedersteiner Str. 29, D-80802 München, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Oliveto A, Poling J, Kosten TR, Gonsai K. Isradipine and dextromethorphan in methadone-maintained humans under a naloxone discrimination procedure. Eur J Pharmacol 2004; 491:157-68. [PMID: 15140632 DOI: 10.1016/j.ejphar.2004.03.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2003] [Revised: 03/04/2004] [Accepted: 03/10/2004] [Indexed: 10/26/2022]
Abstract
In seven methadone-maintained human participants trained to distinguish between a low dose of naloxone (0.15 mg/70 kg, i.m.; i.e., Drug A) and placebo (i.e., Drug B) under an instructed novel-response drug discrimination procedure, the calcium channel blocker isradipine (0-10 mg/70 kg, p.o.; N=7) and the N-methyl-D-aspartic acid (NMDA) receptor antagonist dextromethorphan (0-60 mg/70 kg, p.o.; N=6) were tested each alone and in combination with the training dose of naloxone. Isradipine alone produced some naloxone- and novel-appropriate responding, minimal changes in self-reports and decreases in blood pressure. Dextromethorphan alone produced some novel-appropriate responding and minimal changes in self-reports and vital signs. When combined with naloxone, isradipine significantly attenuated naloxone-occasioned responding, without increasing novel-appropriate responding, and attenuated naloxone-induced increases in opioid receptor antagonist ratings and ratings measuring sedation. Dextromethorphan significantly attenuated naloxone-appropriate responding, increased novel-appropriate responding, and enhanced naloxone's effects on ratings of dysphoric effects. These results suggest that isradipine attenuates and dextromethorphan enhances some of the behavioral effects of naloxone in opioid-dependent humans.
Collapse
Affiliation(s)
- Alison Oliveto
- CT and VA Connecticut Healthcare System, Yale University, New Haven, 950 Campbell Avenue, Psychiatry 116A-4, Building 36, West Haven, CT 06516, USA.
| | | | | | | |
Collapse
|
38
|
Abstract
We hypothesized that in humans, as in animals, isradipine, a dihydropyridine-class calcium channel antagonist, would antagonize cocaine's rewarding effects, based on preclinical evidence that isradipine inhibits cocaine-mediated increases in mesolimbic dopamine (DA), thereby reducing cocaine's abuse liability. Confirmation of our hypothesis would make isradipine a promising medication for treating cocaine dependence. Eighteen male and female volunteers (mean age, 32.6 years) who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for cocaine dependence participated in a double-blind, placebo-controlled, crossover study. Subjects received placebo or sustained-release (SR) low-dose or high-dose isradipine (15 or 30 mg), plus placebo or low-dose or high-dose cocaine HCl (0.325 or 0.650 mg/kg), for 9 treatment sessions separated by a 2-day interval. Standardized assessments of abuse liability, including a choice procedure to determine preference for cocaine with and without isradipine over monetary incentives, were conducted at scheduled intervals. Cocaine administration produced dose-related prototypic increases in stimulant-related effects, including euphoria, and drug preference over monetary incentives. Isradipine lacked any stimulant or abuse liability effects or the propensity to elicit craving, and it did not antagonize any of cocaine's stimulant-related effects associated with its abuse liability. In conclusion, SR isradipine (up to 30 mg) does not antagonize cocaine's rewarding effects in cocaine-dependent individuals. While higher isradipine doses may have been more effective at antagonizing cocaine reward, we could not test such doses due to the risk of serious adverse events. Also, isradipine-mediated inhibition of mesolimbic DA release may be an ineffective treatment of cocaine dependence.
Collapse
Affiliation(s)
- Bankole A Johnson
- Department of Psychiatry, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA.
| | | | | | | | | |
Collapse
|
39
|
Podzolkov VI, Bartieva DM, Makolkin VI. [Isradipine-SRO: antihypertensive efficacy, central and peripheral hemodynamic effects in patients with hypertensive disease]. Kardiologiia 2003; 43:33-8. [PMID: 12891309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
AIM To assess antihypertensive efficacy of isradipine, to study its effects on central and peripheral hemodynamics, and to investigate relationships between state of microcirculation and response to treatment. MATERIAL AND METHODS Isradipine was given for 12 weeks to 30 patients (16 men, 14 women, mean age 50.2+/-9.8 years) with I-II stage mild and moderate hypertension. Twenty four hour blood pressure monitoring, assessment of parameters of central hemodynamics and state of microcirculation were carried out before and after 12 weeks of isradipine administration. RESULTS Administration of isradipine was associated with improved sense of well-being and significant lowering of 24-hour, diurnal and nocturnal systolic/diastolic blood pressure (by 6.4/12.7, 7.6/9.4, 10.5/13.4%, respectively). Average 24-hour heart rate increased mainly during daytime (by 10.6%). Mean hemodynamic blood pressure was lowered by 16.3% due to reduction of total peripheral vascular resistance. There occurred redistribution of types of microcirculation with increase of proportion of normocirculatory and decrease - of spastic types. Changes of parameters of microcirculation at rest and during functional tests evidenced for resolution of baseline arteriolar spasm, stasis and venous congestion in microcirculatory vascular bed. Patients who responded to isradipine more often had spastic (50%) and congestive (35%) types of microcirculation. Patients with hyperemic type did not respond to isradipine. Most frequent side effect was flushing (23.3%) because of which 2 patients stopped taking the drug.
Collapse
|
40
|
Abstract
Thyroid hormones are known to influence various processes of cell differentiation. Recently, it was reported that hypothyroidism reduces the sensitivity to Ca2+-channel antagonists in the rat uterus. We examined the sensitivity to dihydropyridines of the uterus from mice that had reduced thyroid hormone levels. Isradipine relaxed with the same potency precontracted uterine muscle strips from control and hypothyroid mice, independently from a pseudo-pregnant state. These results demonstrate that hypothyroidism does not change dihydropyridine sensitivity (i.e., the pattern of Ca2+-channel expression) in the murine uterus.Key words: uterus, smooth muscle, Ca2+channel, isradipine.
Collapse
Affiliation(s)
- Jörg W Wegener
- Institute of Pharmacology and Toxicology, Technische Universität München, Biedersteiner Strasse 29, 80202 Munich, Germany.
| | | | | |
Collapse
|
41
|
Yamaguchi S, Zhorov BS, Yoshioka K, Nagao T, Ichijo H, Adachi-Akahane S. Key roles of Phe1112 and Ser1115 in the pore-forming IIIS5-S6 linker of L-type Ca2+ channel alpha1C subunit (CaV 1.2) in binding of dihydropyridines and action of Ca2+ channel agonists. Mol Pharmacol 2003; 64:235-48. [PMID: 12869628 DOI: 10.1124/mol.64.2.235] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Voltage-dependent L-type Ca2+ channels are modulated by the binding of Ca2+ channel antagonists and agonists to the pore-forming alpha1c subunit (CaV 1.2). We recently identified Ser1115 in IIIS5-S6 linker of alpha1C subunit as a critical determinant of the action of 1,4-dihydropyridine agonists. In this study, we applied alanine-scanning mutational analysis in IIIS5-S6 linker of rat brain alpha1C subunit (rbCII) to illustrate the role of pore-forming IIIS5-S6 linker in the action of Ca2+ channel modulators. Ca2+ channel currents through wild-type (rbCII) or mutated alpha1C subunits, transiently expressed in BHK6 cells with beta1a and alpha2/delta subunits, were analyzed. The replacement of Phe1112 by Ala (F1112A) significantly impaired the sensitivity to Ca2+ channel agonists (S)-(-)-Bay k 8644 and FPL-64176, and modestly to 1,4-dihydropyridine (DHP) antagonists. The low sensitivity of F1112A and S1115A to DHP antagonists was consistent with the reduced binding affinity for [3H](+)PN200-110. The replacement of Phe1112 by Tyr, but not by Ala, restored the long openings produced by FPL-64176, thus indicating the critical role of aromatic ring of Phe1112 in the Ca2+ channel agonist action. Interestingly, double-mutant Ca2+ channel (F1112A/S1115A) failed to discriminate between Ca2+ channel agonist (S)-(-)-1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-[trifluoromethyl] phenyl)-3-pyridine carboxylic acid methyl ester (Bay k 8644) and antagonist (R)-(+)-Bay k 8644 and was blocked by the two enantiomers in an identical manner. These results indicate that both Phe1112 and Ser1115 in linker IIIS5-S6 are required for the action of Ca2+ channel agonists. A model of the DHP receptor is proposed to visualize possible interactions of Phe1112, Ser1115, and other DHP-sensing residues with a typical DHP ligand nifedipine.
Collapse
Affiliation(s)
- Shinji Yamaguchi
- Laboratory of Cell Signaling, Graduate school of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | | | | | | | |
Collapse
|
42
|
Koschak A, Reimer D, Walter D, Hoda JC, Heinzle T, Grabner M, Striessnig J. Cav1.4alpha1 subunits can form slowly inactivating dihydropyridine-sensitive L-type Ca2+ channels lacking Ca2+-dependent inactivation. J Neurosci 2003; 23:6041-9. [PMID: 12853422 PMCID: PMC6740341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
The neuronal L-type calcium channels (LTCCs) Cav1.2alpha1 and Cav1.3alpha1 are functionally distinct. Cav1.3alpha1 activates at lower voltages and inactivates more slowly than Cav1.2alpha1, making it suitable to support sustained L-type Ca2+ inward currents (ICa,L) and serve in pacemaker functions. We compared the biophysical and pharmacological properties of human retinal Cav1.4alpha1 using the whole-cell patch-clamp technique after heterologous expression in tsA-201 cells with other L-type alpha1 subunits. Cav1.4alpha1-mediated inward Ba2+ currents (IBa) required the coexpression of alpha2delta1 and beta3 or beta2a subunits and were detected in a lower proportion of transfected cells than Cav1.3alpha1. IBa activated at more negative voltages (5% activation threshold; -39mV; 15 mm Ba2+) than Cav1.2alpha1 and slightly more positive than Cav1.3alpha1. Voltage-dependent inactivation of IBa was slower than for Cav1.2alpha1 and Cav1.3alpha1( approximately 50% inactivation after 5 sec; alpha2delta1 + beta3 coexpression). Inactivation was not increased with Ca2+ as the charge carrier, indicating the absence of Ca2+-dependent inactivation. Cav1.4alpha1 exhibited voltage-dependent, G-protein-independent facilitation by strong depolarizing pulses. The dihydropyridine (DHP)-antagonist isradipine blocked Cav1.4alpha1 with approximately 15-fold lower sensitivity than Cav1.2alpha1 and in a voltage-dependent manner. Strong stimulation by the DHP BayK 8644 was found despite the substitution of an otherwise L-type channel-specific tyrosine residue in position 1414 (repeat IVS6) by a phenylalanine. Cav1.4alpha1 + alpha2delta1 + beta channel complexes can form LTCCs with intermediate DHP antagonist sensitivity lacking Ca2+-dependent inactivation. Their biophysical properties should enable them to contribute to sustained ICa,L at negative potentials, such as required for tonic neurotransmitter release in sensory cells and plateau potentials in spiking neurons.
Collapse
Affiliation(s)
- Alexandra Koschak
- Institut für Pharmazie, Abteilung Pharmakologie und Toxikologie, A-6020 Innsbruck, Austria
| | | | | | | | | | | | | |
Collapse
|
43
|
Ferraz MR, Ferraz MMD, Santos R, de Moura RS. Preventing L-NAME inhibitory effects on rat sexual behavior with hydralazine, isradipine or captopril co-treatment. Pharmacol Biochem Behav 2003; 75:265-72. [PMID: 12873615 DOI: 10.1016/s0091-3057(03)00077-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effects of the chronic oral treatment with N(G)-nitro-L-arginine methyl ester (L-NAME), separately or in combination with isradipine, captopril or hydralazine, on standard and temporal patterning sexual behavior of male rats were evaluated. L-Arginine and filtered water were used as control. L-NAME treatment decreased the copulatory rate and hit rate factors of sexual behavior. However, the initiation factor and temporal patterning were less modified by the drug. After 14 days of L-NAME treatment suspension the male rat sexual response was recovered. The three antihypertensive agents were able to reverse partially or totally the inhibitory effects of L-NAME, suggesting that the chronic oral treatment with L-NAME induces penile erection dysfunction by peripheral mechanisms. The present results suggest that chronic oral treatment with nitric oxide (NO) synthase inhibitor can be a relevant and powerful peripheral erectile dysfunction model to evaluate the effects of drugs on erectile function of male rats.
Collapse
Affiliation(s)
- Marcos Rochedo Ferraz
- Department of Pharmacology and Psychobiology, Institute de Biology, State University of Rio de Janeiro, Av. 28 de Setembro, 87-Fundos, 20551-030, Rio de Janeiro, Brazil.
| | | | | | | |
Collapse
|
44
|
Muravyov AV, Meiselman HJ, Yakusevich VV, Zamishlayev AV. Effects of antihypertensive therapy on hemorheological profiles in female hypertensive patients with initially low or high whole blood viscosity. Clin Hemorheol Microcirc 2003; 26:125-35. [PMID: 12082261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
This study was designed to examine changes of hemorheological parameters in essential arterial hypertension subjects following antihypertensive drug therapy. Eighty two female subjects were enrolled, and sub-divided into two groups based upon their high shear whole blood viscosity being lower (L) or higher (H) than normal controls. Equal numbers of L and H subjects were then treated for four weeks with one of four agents: angiotensin-converting enzyme inhibitor (ACE-inhibitor, Spirapril - 6 mg/day); calcium antagonist (Isradipin - 5 mg/day); beta-1-blocker (Talinolol - 100 mg/day); diuretic (Indapamide - 1.5 mg/day). Both prior to and following drug treatment for six weeks, hemorheological measurements included plasma viscosity; high and low shear whole blood viscosity, hematocrit, fibrinogen and RBC aggregation. Treatment with each of the four drugs significantly (p<0.05) reduced blood pressure in both the L and H groups. However, the hemorheological effects of antihypertensive drug therapy differed markedly between groups: plasma and whole blood viscosity were significantly elevated in the L groups whereas these parameters were significantly decreased in the H groups. Fibrinogen levels and RBC aggregation decreased in both groups, whereas hematocrit was unaffected. These results thus suggest that the rheologic effects of antihypertensive drug therapy depend strongly on the initial, pre-treatment status of the subject, and that for some subjects, such therapy can result in adverse hemorheological alterations.
Collapse
Affiliation(s)
- Alexei V Muravyov
- Department of Medicine and Biology, University of Yaroslavl, 150000, Yaroslavl, Russia.
| | | | | | | |
Collapse
|
45
|
Jacques D, Bkaily G, Jasmin G, D'Orléans-Juste P, Chahine M. Isradipine prevents the development of spontaneously occurring cardiac necrosis in cardiomyopathic hamster. Can J Physiol Pharmacol 2003; 81:120-4. [PMID: 12710524 DOI: 10.1139/y03-021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies on the heart necrotizing process at the early stages of hamster polymyopathy have led us to believe that this hereditary disease derives from an anomalous transmembrane ion flux due to the presence of slow Na+ channels that contribute to intracellular Na+ accumulation which promote intracellular Ca2+ overload via the Ca2+ influx through the Na+-Ca2+ exchanger. In the present study, we investigated the potential beneficial effect of chronic treatment with a dual L-type Ca2+ and slow Na+ channel blockers isradipine, on the development of necrosis in myopathic hamster hearts. Young cardiomyopathic (CM) hamsters (CMH) were treated with isradipine (0.1 mg x kg(-1) x day(-1)) and nifedipine (1 mg x kg(-1) x day(-1)) for 4 consecutive weeks. Microscopic assessments were carried out in staged serial paraffin sections of heart ventricles from tissues freshly dissected at autopsy. In comparison with control nontreated hearts, which exhibited numerous necrotic calcific foci, myolytic lesions, and dilated right ventricle, isradipine treatment prevented, in a significant manner, all the above spontaneous pathological changes, while nifedipine had no effect. Our present observations provide evidence for the first time that in vivo treatment with a DHP Ca2+ channel blocker, isradipine, is cardioprotective against the development of necrosis in hereditary cardiomyopathy in the hamster. It is possible that the protective effect of isradipine in CMH could be largely due to the indirect blockade of Ca2+ influx through the Na+-Ca2+ exchanger as well as to possible direct blockade of Ca2+ influx through the T-type Ca2+ channel.
Collapse
Affiliation(s)
- Danielle Jacques
- Department of Anatomy and Cell Biology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | | | | | | | | |
Collapse
|
46
|
Abstract
Nine cocaine abusers with cerebral blood flow (CBF) deficits (hypo-perfused areas) on HMPAO SPECT scans were compared to six without these deficits after six doses of isradipine (5 mg TID). When comparing the scan before isradipine to that after using SPM analysis, the ratio of hypo- to hyper-fusion showed a 16% increase in the maximum Z scores and 30% fewer areas of hypo-perfusion among those cocaine abusers with deficits. These deficits may represent segmental cerebral vasospasm that was reversed by this vasodilating agent in cocaine abusers with areas of hypo-perfusion (deficits) as baseline.
Collapse
Affiliation(s)
- P C H Gottschalk
- Department of Psychiatry, Yale University School of Medicine and the VA Connecticut Healthcare System, West Haven, Conn 06516, USA
| | | |
Collapse
|
47
|
Vasin MV, Ushakov IB, Koroleva LV, Lairov IA, Radchenko SN. In vitro response of mitochondrial succinate oxidase system to epinephrine in human blood lymphocytes from health individuals and patients with neurocirculatory dystonia. Bull Exp Biol Med 2002; 134:393-6. [PMID: 12533769 DOI: 10.1023/a:1021976718941] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2002] [Indexed: 11/12/2022]
Abstract
Activities of succinate dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (hyaloplasmic and mitochondrial: alpha-GPDHH and alpha-GPDHM) in peripheral blood lymphocytes, and the response of SDH activity to exogenous epinephrine in vitro (the epinephrine test) were studied in 20 healthy subjects and 46 patients with hypertensive neurocirculatory dystonia. Activities of SDH, alpha-GPDHH, and alpha-GPDHM in blood lymphocytes and SDH adrenoreactivity in epinephrine test were higher in patients than in healthy controls. Treatment with hypotensive agents (isradipin and pyrroxan) moderated adrenoreactivity. Phytotherapy normalized the baseline activities of succinate oxidase system and alpha-glycerophosphate pathway in blood lymphocytes.
Collapse
Affiliation(s)
- M V Vasin
- State Research Institute of Military Medicine, Moscow, Russia
| | | | | | | | | |
Collapse
|
48
|
Kantas E, Cetin A, Kaya T, Cetin M. Effect of magnesium sulfate, isradipine, and ritodrine on contractions of myometrium: pregnant human and rat. Acta Obstet Gynecol Scand 2002; 81:825-30. [PMID: 12225296 DOI: 10.1034/j.1600-0412.2002.810904.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Magnesium sulfate, isradipine, and ritodrine are smooth muscle relaxants used for treating preterm labor. The aim of this study is to investigate the action profile of these drugs on the amplitude and frequency of spontaneous contractions of isolated myometrial strips of pregnant human and rat. MATERIAL AND METHODS Isolated myometrial strips were obtained from humans undergoing elective cesarean section at term pregnancy and Wistar albino rats on gestational days 19-21. These strips were mounted in organ baths for recording of isometric tensions. The effect of magnesium sulfate, isradipine, and ritodrine on the amplitude and frequency of spontaneous contractions was compared with the anova test. RESULTS Ritodrine (10-8-10-5 M) concentration-dependently inhibited the frequency and amplitude of spontaneous contractions of myometrial strips. At 10-4 M, tachyphylaxis of ritodrine occurred and contractions started again. Magnesium sulfate (10-7-10-4 M) inhibited the frequency but did not change the amplitude of the spontaneous contractions. Isradipine (10-7-10-4 M) had a concentration-related inhibitor effect on both the frequency and amplitude of the spontaneous contractions. The effects of magnesium sulfate, isradipine, and ritodrine were considerably similar in myometrium strips obtained from pregnant rats and humans. CONCLUSIONS Because of tachyphylaxis, the effectiveness of ritodrine is limited for inhibition of myometrial contractions. Magnesium sulfate reduced the frequency of spontaneous contractions without affecting the amplitude. Isradipine may be an interesting therapeutic alternative in situations where inhibition of uterine activity is desirable.
Collapse
Affiliation(s)
- Emine Kantas
- Department of Obstetrics and Gynecology, Cumhuriyet University School of Medicine, 58140 Sivas, Turkey
| | | | | | | |
Collapse
|
49
|
Gullapalli S, Gurumoorthy K, Kaul CL, Ramarao P. Role of L-type Ca2+ channels in attenuated morphine antinociception in streptozotocin-diabetic rats. Eur J Pharmacol 2002; 435:187-94. [PMID: 11821025 DOI: 10.1016/s0014-2999(01)01593-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The role of L-type Ca2+ channels in morphine antinociception was studied in streptozotocin-induced diabetic and control rats, using [3H]PN200-110 [isopropyl 4-(2,1,3-benzoxadiazol-4-yl)-1,4-dihydro-2,6-dimethyl-5-methoxycabonylpyridine-3-caboxylate] binding (0.005-1.0 nmol/l) and rat whole brain membranes, to determine if the attenuation of morphine antinociception was related to alterations in dihydropyridine-sensitive Ca2+ channel binding characteristics. The tail-flick antinociceptive effect of morphine (4 mg/kg, i.p.) was significantly reduced in diabetic rats in comparison to that in controls. Nimodipine (0.1-3 mg/kg, i.p.) did not produce antinociception but significantly potentiated the morphine response in control rats. Nimodipine (0.3-3 mg/kg, i.p.) reversed the attenuation of morphine antinociception in a dose-dependent manner in diabetic rats. Moreover, insulin (2 U/kg, s.c.) [correction of mu/kg] reversed the attenuated morphine antinociception in streptozotocin-diabetic rats. A significant increase in the Bmax (+41%) of [3H]PN200-110 binding was observed in diabetic rat brain membranes compared to that in control rats. However, there was no change in affinity (Kd) value of [3H]PN200-110. The reduced morphine response in diabetic rats, in accordance with up-regulation of dihydropyridine sites, may be due to an increased Ca2+ influx through L-type channels. These results suggest a functional role of L-type Ca2+ channels in morphine antinociception and the diabetic state may lead to alterations in their density.
Collapse
Affiliation(s)
- Srinivas Gullapalli
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector 67, Phase-X, S.A.S. Nagar-160 062, Punjab, India
| | | | | | | |
Collapse
|
50
|
Abstract
Recently, we reported that, whereas in cerebral arteries of the adult a majority of norepinephrine (NE)-induced increase in intracellular Ca2+ concentration ([Ca2+]i) comes from release of the sarcoplasmic reticulum (SR) Ca2+ stores, in the fetus the SR Ca2+ stores are relatively small, and NE-induced increase in [Ca2+]i results mainly from activation of plasma membrane L-type Ca2+ channels (20). In an effort to establish further the role of L-type Ca2+ channels in the developing cerebral arteries, we tested the hypothesis that, in the fetus, increased reliance on plasmalemmal L-type Ca2+ channels is mediated, in part, by increased L-type Ca2+ channel density. We used 3H-labeled (+)isopropyl-4-(2,1,3-benzoxadiazol-4-y1)-1,4-dihydro-(2,6-dimethyl-5-methoxycarbonyl)pyridine-3-carboxylate (PN200-110, isradipine) to measure L-type Ca2+ channel density (Bmax) in the cerebral arteries, common carotid artery (CCA), and descending aortae of fetal (approximately 140 gestation days), newborn (7-10 days), and adult sheep. In the cerebral and common carotid arteries, B(max) values (fmol/mg protein) of fetuses and newborns were significantly greater than those of adults. Western immunoblotting assay also revealed that the density of L-type Ca2+ channel protein in the cerebral arteries and CCA was about twofold greater in the fetus than the adult. Finally, compared with the adult, fetal cerebral arteries demonstrated a significantly greater maximum tension and [Ca2+]i in response to stimulation with the L-type Ca2+ channel agonist Bay K 8644. In addition, Bay K 8644-stimulated fetal vessels demonstrated a maximal tension and [Ca2+]i similar to that observed in response to stimulation with 10(-4) NE. These results support the idea that fetal cerebrovascular smooth muscle relies more on extracellular Ca2+ and L-type Ca2+ channels for contraction than does the adult and that this increased reliance is mediated, in part, by greater L-type Ca2+ channel density. This may have important implications in the regulation of cerebral blood flow in the developing organism.
Collapse
MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Age Factors
- Animals
- Animals, Newborn
- Aorta/chemistry
- Aorta/embryology
- Aorta/physiology
- Calcium/blood
- Calcium Channel Agonists/pharmacology
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/analysis
- Cerebral Arteries/chemistry
- Cerebral Arteries/embryology
- Cerebral Arteries/physiology
- Cerebrovascular Circulation/drug effects
- Cerebrovascular Circulation/physiology
- Immunoblotting
- Isradipine/pharmacology
- Muscle, Smooth, Vascular/chemistry
- Muscle, Smooth, Vascular/physiology
- Norepinephrine/pharmacology
- Radioligand Assay
- Sheep
- Tritium
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
- Vasoconstrictor Agents/pharmacology
Collapse
Affiliation(s)
- Arlin B Blood
- Center for Perinatal Biology, Department of Physiology/Pharmacology, School of Medicine, Loma Linda University, Loma Linda, California 92350, USA
| | | | | | | | | |
Collapse
|