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Van NTH, Kim WK, Nam JH. Challenges in the Therapeutic Targeting of KCa Channels: From Basic Physiology to Clinical Applications. Int J Mol Sci 2024; 25:2965. [PMID: 38474212 PMCID: PMC10932353 DOI: 10.3390/ijms25052965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 03/14/2024] Open
Abstract
Calcium-activated potassium (KCa) channels are ubiquitously expressed throughout the body and are able to regulate membrane potential and intracellular calcium concentrations, thereby playing key roles in cellular physiology and signal transmission. Consequently, it is unsurprising that KCa channels have been implicated in various diseases, making them potential targets for pharmaceutical interventions. Over the past two decades, numerous studies have been conducted to develop KCa channel-targeting drugs, including those for disorders of the central and peripheral nervous, cardiovascular, and urinary systems and for cancer. In this review, we synthesize recent findings regarding the structure and activating mechanisms of KCa channels. We also discuss the role of KCa channel modulators in therapeutic medicine. Finally, we identify the major reasons behind the delay in bringing these modulators to the pharmaceutical market and propose new strategies to promote their application.
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Affiliation(s)
- Nhung Thi Hong Van
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
| | - Woo Kyung Kim
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
- Department of Internal Medicine, Graduate School of Medicine, Dongguk University, Goyang 10326, Republic of Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
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2
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Nageeb Hasan SM, Clarke CL, McManamon Strand TP, Bambico FR. Putative pathological mechanisms of late-life depression and Alzheimer's Disease. Brain Res 2023:148423. [PMID: 37244602 DOI: 10.1016/j.brainres.2023.148423] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 05/18/2023] [Accepted: 05/22/2023] [Indexed: 05/29/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder that is characterized by progressive impairment in cognition and memory. AD is accompanied by several neuropsychiatric symptoms, with depression being the most prominent. Although depression has long been known to be associated with AD, controversial findings from preclinical and clinical studies have obscured the precise nature of this association. However recent evidence suggests that depression could be a prodrome or harbinger of AD. Evidence indicates that the major central serotonergic nucleus-the dorsal raphe nucleus (DRN)-shows very early AD pathology: neurofibrillary tangles made of hyperphosphorylated tau protein and degenerated neurites. AD and depression share common pathophysiologies, including functional deficits of the serotonin (5-HT) system. 5-HT receptors have modulatory effects on the progression of AD pathology i.e., reduction in Aβ load, increased hyper-phosphorylation of tau, decreased oxidative stress etc. Moreover, preclinical models show a role for specific channelopathies that result in abnormal regional activational and neuroplasticity patterns. One of these concerns the pathological upregulation of the small conductance calcium-activated potassium (SK) channel in corticolimbic structure. This has also been observed in the DRN in both diseases. The SKC is a key regulator of cell excitability and long-term potentiation (LTP). SKC over-expression is positively correlated with aging and cognitive decline, and is evident in AD. Pharmacological blockade of SKCs has been reported to reverse symptoms of depression and AD. Thus, aberrant SKC functioning could be related to depression pathophysiology and diverts its late-life progression towards the development of AD. We summarize findings from preclinical and clinical studies suggesting a molecular linkage between depression and AD pathology. We also provide a rationale for considering SKCs as a novel pharmacological target for the treatment of AD-associated symptoms.
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Affiliation(s)
- S M Nageeb Hasan
- Department of Psychology, Memorial University of Newfoundland and Labrador, Newfoundland and Labrador, A1B3Xs, Canada.
| | - Courtney Leigh Clarke
- Department of Psychology, Memorial University of Newfoundland and Labrador, Newfoundland and Labrador, A1B3Xs, Canada
| | | | - Francis Rodriguez Bambico
- Department of Psychology, Memorial University of Newfoundland and Labrador, Newfoundland and Labrador, A1B3Xs, Canada; Behavioural Neurobiology Laboratory, Centre for Addiction and Mental Health, Toronto, ON, M5T1R8, Canada
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3
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Kadam M, Perveen S, Kushwah N, Prasad D, Panjwani U, Kumar B, Khan N. Elucidating the role of hypoxia/reoxygenation in hippocampus-dependent memory impairment: do SK channels play role? Exp Brain Res 2021; 239:1747-1763. [PMID: 33779792 DOI: 10.1007/s00221-021-06095-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 03/19/2021] [Indexed: 10/21/2022]
Abstract
Professionals and mountaineers often face the problem of reperfusion injury due to re-oxygenation, upon their return to sea-level after sojourn at high altitude. Small conductance calcium-activated potassium channels (SK channels) have a role in regulating hippocampal synaptic plasticity. However, the role of SK channels under hypoxia-reoxygenation (H/R) is unknown. The present study hypothesized that SK channels play a significant role in H/R induced cognitive dysfunction. Sprague-Dawley rats were exposed to simulated HH (25,000 ft) continuously for 7 days followed by reoxygenation periods 3, 6, 24, 48, 72 and 120 h. It was observed that H/R exposure caused impairment in spatial memory as indicated by increased latency (p < 0.001) and pathlength (p < 0.001). The SK1 channel expression increased upon HH exposure (102.89 ± 7.055), which abrogated upon reoxygenation. HH exposure results in an increase in SK2 (CA3, 297.67 ± 6.69) and SK3 (CA1, 246 ± 5.13) channels which continued to increase gradually upon reoxygenation. The number of pyknotic cells (24 ± 2.03) (p < 0.01) and the expression of caspase-3 increased with HH exposure, which continued in the reoxygenation group (177.795 ± 1.264). Similar pattern was observed in lipid peroxidation (p < 0.001), LDH activity (p < 0.001) and ROS production (p < 0.001). A positive correlation of memory, cell death and oxidative stress indicates that H/R exposure increases oxidative stress coupled with SK channel expression, which may play a role in H/R-induced cognitive decline and neurodegeneration.
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Affiliation(s)
- Manisha Kadam
- Neurobiology Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Developmental Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
| | - Saba Perveen
- Neurobiology Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Developmental Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
| | - Neetu Kushwah
- Neurobiology Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Developmental Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
| | - Dipti Prasad
- Neurobiology Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Developmental Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
| | - Usha Panjwani
- Neurobiology Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Developmental Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
| | - Bhuvnesh Kumar
- Neurobiology Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Developmental Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
| | - Nilofar Khan
- Neurobiology Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Developmental Organization (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India.
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Kshatri AS, Gonzalez-Hernandez A, Giraldez T. Physiological Roles and Therapeutic Potential of Ca 2+ Activated Potassium Channels in the Nervous System. Front Mol Neurosci 2018; 11:258. [PMID: 30104956 PMCID: PMC6077210 DOI: 10.3389/fnmol.2018.00258] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/06/2018] [Indexed: 12/21/2022] Open
Abstract
Within the potassium ion channel family, calcium activated potassium (KCa) channels are unique in their ability to couple intracellular Ca2+ signals to membrane potential variations. KCa channels are diversely distributed throughout the central nervous system and play fundamental roles ranging from regulating neuronal excitability to controlling neurotransmitter release. The physiological versatility of KCa channels is enhanced by alternative splicing and co-assembly with auxiliary subunits, leading to fundamental differences in distribution, subunit composition and pharmacological profiles. Thus, understanding specific KCa channels’ mechanisms in neuronal function is challenging. Based on their single channel conductance, KCa channels are divided into three subtypes: small (SK, 4–14 pS), intermediate (IK, 32–39 pS) and big potassium (BK, 200–300 pS) channels. This review describes the biophysical characteristics of these KCa channels, as well as their physiological roles and pathological implications. In addition, we also discuss the current pharmacological strategies and challenges to target KCa channels for the treatment of various neurological and psychiatric disorders.
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Affiliation(s)
- Aravind S Kshatri
- Department of Basic Medical Sciences, Medical School, Universidad de La Laguna, Tenerife, Spain.,Instituto de Tecnologias Biomedicas, Universidad de La Laguna, Tenerife, Spain
| | - Alberto Gonzalez-Hernandez
- Department of Basic Medical Sciences, Medical School, Universidad de La Laguna, Tenerife, Spain.,Instituto de Tecnologias Biomedicas, Universidad de La Laguna, Tenerife, Spain
| | - Teresa Giraldez
- Department of Basic Medical Sciences, Medical School, Universidad de La Laguna, Tenerife, Spain.,Instituto de Tecnologias Biomedicas, Universidad de La Laguna, Tenerife, Spain
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Huang CG, Chacron MJ. SK channel subtypes enable parallel optimized coding of behaviorally relevant stimulus attributes: A review. Channels (Austin) 2017; 11:281-304. [PMID: 28277938 DOI: 10.1080/19336950.2017.1299835] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Ion channels play essential roles toward determining how neurons respond to sensory input to mediate perception and behavior. Small conductance calcium-activated potassium (SK) channels are found ubiquitously throughout the brain and have been extensively characterized both molecularly and physiologically in terms of structure and function. It is clear that SK channels are key determinants of neural excitability as they mediate important neuronal response properties such as spike frequency adaptation. However, the functional roles of the different known SK channel subtypes are not well understood. Here we review recent evidence from the electrosensory system of weakly electric fish suggesting that the function of different SK channel subtypes is to optimize the processing of independent but behaviorally relevant stimulus attributes. Indeed, natural sensory stimuli frequently consist of a fast time-varying waveform (i.e., the carrier) whose amplitude (i.e., the envelope) varies slowly and independently. We first review evidence showing how somatic SK2 channels mediate tuning and responses to carrier waveforms. We then review evidence showing how dendritic SK1 channels instead determine tuning and optimize responses to envelope waveforms based on their statistics as found in the organism's natural environment in an independent fashion. The high degree of functional homology between SK channels in electric fish and their mammalian orthologs, as well as the many important parallels between the electrosensory system and the mammalian visual, auditory, and vestibular systems, suggest that these functional roles are conserved across systems and species.
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Affiliation(s)
- Chengjie G Huang
- a Department of Physiology , McGill University , Montreal , QC , Canada
| | - Maurice J Chacron
- a Department of Physiology , McGill University , Montreal , QC , Canada
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Moreno M, Giralt E. Three valuable peptides from bee and wasp venoms for therapeutic and biotechnological use: melittin, apamin and mastoparan. Toxins (Basel) 2015; 7:1126-50. [PMID: 25835385 PMCID: PMC4417959 DOI: 10.3390/toxins7041126] [Citation(s) in RCA: 205] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 03/18/2015] [Accepted: 03/25/2015] [Indexed: 12/14/2022] Open
Abstract
While knowledge of the composition and mode of action of bee and wasp venoms dates back 50 years, the therapeutic value of these toxins remains relatively unexploded. The properties of these venoms are now being studied with the aim to design and develop new therapeutic drugs. Far from evaluating the extensive number of monographs, journals and books related to bee and wasp venoms and the therapeutic effect of these toxins in numerous diseases, the following review focuses on the three most characterized peptides, namely melittin, apamin, and mastoparan. Here, we update information related to these compounds from the perspective of applied science and discuss their potential therapeutic and biotechnological applications in biomedicine.
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Affiliation(s)
- Miguel Moreno
- Chemistry and Molecular Pharmacology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri i Reixac, 10, Barcelona 08028, Spain.
| | - Ernest Giralt
- Chemistry and Molecular Pharmacology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri i Reixac, 10, Barcelona 08028, Spain.
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Lam J, Coleman N, Garing ALA, Wulff H. The therapeutic potential of small-conductance KCa2 channels in neurodegenerative and psychiatric diseases. Expert Opin Ther Targets 2013; 17:1203-20. [PMID: 23883298 DOI: 10.1517/14728222.2013.823161] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION KCa2 or small-conductance Ca(2+)-activated K(+) channels (SK) are expressed in many areas of the central nervous system where they participate in the regulation of neuronal afterhyperpolarization and excitability, and also serve as negative feedback regulators on the glutamate-NMDA pathway. AREAS COVERED This review focuses on the role of KCa2 channels in learning and memory and their potential as therapeutic targets for Alzheimer's and Parkinson's disease, ataxia, schizophrenia and alcohol dependence. EXPERT OPINION There currently exists relatively solid evidence supporting the use of KCa2 activators for ataxia. Genetic KCa2 channel suppression in deep cerebellar neurons induces ataxia, while KCa2 activators like 1-EBIO, SKA-31 and NS13001 improve motor deficits in mouse models of episodic ataxia (EA) and spinal cerebellar ataxia (SCA). Use of KCa2 activators for ataxia is further supported by a report that riluzole improves ataxia in a small clinical trial. Based on accumulating literature evidence, KCa2 activators further appear attractive for the treatment of alcohol dependence and withdrawal. Regarding Alzheimer's disease, Parkinson's disease and schizophrenia, further research, including long-term studies in disease relevant animal models, will be needed to determine whether KCa2 channels constitute valid targets and whether activators or inhibitors would be needed to positively affect disease outcomes.
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Affiliation(s)
- Jenny Lam
- University of California, Davis, Department of Pharmacology , 451 Health Sciences Drive, Genome and Biomedical Sciences Facility Room 3502, Davis, CA 95616 , USA +1 530 754 6135 ; +1 530 752 7710 ;
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8
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Affiliation(s)
- John P. Adelman
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239;
| | - James Maylie
- Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, Oregon 97239;
| | - Pankaj Sah
- The Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, 4072, Australia;
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9
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Vicente MI, Costa PF, Lima PA. Galantamine inhibits slowly inactivating K+ currents with a dual dose–response relationship in differentiated N1E-115 cells and in CA1 neurones. Eur J Pharmacol 2010; 634:16-25. [DOI: 10.1016/j.ejphar.2010.02.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 01/26/2010] [Accepted: 02/13/2010] [Indexed: 11/15/2022]
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Zarrindast MR, Sattari-Naeini M, Khalilzadeh A. Involvement of glucose and ATP-sensitive potassium (K+) channels on morphine-induced conditioned place preference. Eur J Pharmacol 2007; 573:133-8. [PMID: 17655841 DOI: 10.1016/j.ejphar.2007.06.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 06/23/2007] [Accepted: 06/28/2007] [Indexed: 11/30/2022]
Abstract
In the present study, the effects of glucose and ATP-sensitive K+ channel compounds on the acquisition of morphine-induced place preference in male mice were investigated. Subcutaneous administration of different doses of morphine (2.5-7.5 mg/kg) produced a dose-dependent conditioned place preference. With a 3-day conditioning schedule, it was found that glucose (100, 200, 500 and 1000 mg/kg), diazoxide (15, 30 and 60 mg/kg) or glibenclamide (3, 6 and 12 mg/kg) did not produce significant place preference or place aversion. Intraperitoneal administration of the glucose (1000 mg/kg) or glibenclamide (6 and 12 mg/kg) with a lower dose of morphine (0.5 mg/kg) elicited the significant conditioned place preference. The response of glibenclamide (6 mg/kg) was reversed by diazoxide (15, 30 and 60 mg/kg). Drug injections had no effects on locomotor activity during the test sessions. It is concluded that glucose and the ATP-sensitive K+ channel may play an active role in morphine reward.
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Affiliation(s)
- Mohammad R Zarrindast
- Department of Pharmacology and Iranian National Center for addiction Studies, Medical Sciences, University of Tehran, Iran.
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Orozco C, García-de-Diego AM, Arias E, Hernández-Guijo JM, García AG, Villarroya M, López MG. Depolarization preconditioning produces cytoprotection against veratridine-induced chromaffin cell death. Eur J Pharmacol 2006; 553:28-38. [PMID: 17045260 DOI: 10.1016/j.ejphar.2006.08.084] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Revised: 08/28/2006] [Accepted: 08/31/2006] [Indexed: 11/28/2022]
Abstract
The hypothesis that K(+) channels and cell depolarization are involved in neuronal death and neuroprotection was tested in bovine chromaffin cells subjected to two treatment periods: the first period (preconditioning period) lasted 6 to 48 h and consisted of treatment with high K(+) solutions or with tetraethylammonium (TEA), a K(+) channel blocker; the second period consisted of incubation with veratridine for 24 h, to cause cell damage. Preconditioning with high K(+) (20-80 mM) or TEA (10-30 mM) for 24 h caused 20-60% cytoprotection against veratridine-induced cell death in bovine chromaffin cells. The absence of Ca(2+) ions during the first 9 h of an 18-h preconditioning period abolished the cytoprotection. Preconditioning with K(+) or TEA increased by 2.5-fold the expression of brain-derived neurotrophic factor and by nearly 2-fold the expression of the antiapoptotic protein Bcl-2. However, preconditioning did not modify the veratridine-evoked Ca(2+) signal. High K(+) shifted the Em by about 10 mV and TEA evoked a transient burst of action potentials superimposed on a sustained depolarization. We conclude that preconditioning may protect chromaffin cells from death by blocking K(+) channels that depolarize the cell and cause a cytosolic Ca(2+) signal, leading to enhanced expression of BDNF and Bcl-2.
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Affiliation(s)
- Camilo Orozco
- Instituto de Farmacología Teófilo Hernando, Departamento de Farmacología, Facultad de Medicina, Universidad Autónoma de Madrid, Arzobispo Morcillo, 4, 28029 Madrid, Spain
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Wang D, Darwish DS, Schreurs BG. Effects of 4-aminopyridine on classical conditioning of the rabbit (Oryctolagus cuniculus) nictitating membrane response. Behav Pharmacol 2006; 17:319-29. [PMID: 16914950 DOI: 10.1097/01.fbp.0000224381.56121.15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A large body of data suggests that potassium channels may play an important role in learning and memory. Previous in-vitro research in a number of species including Hermissenda and the rabbit suggests that a 4-aminopyridine-sensitive transient potassium channel may be involved in classical conditioning. We investigated the effects of in-vivo 4-aminopyridine administration (0.5 mg/kg) on classical conditioning of the rabbit nictitating membrane response using a battery of tests designed to assess the associative, sensory, and motor contributors of 4-aminopyridine to responding. 4-Aminopyridine enhanced both classical conditioning and conditioning-specific reflex modification compared with a saline vehicle control, and these effects had several nonassociative components including an increase in the frequency of responding to both the conditioned and the unconditioned stimuli, suggesting a sensitizing effect of the drug. Although 4-aminopyridine can have peripheral effects, it may also modify cerebellar excitability or hippocampal neurotransmitter balance resulting in heightened responsiveness to stimulation.
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Affiliation(s)
- Desheng Wang
- Department of Physiology and Pharmacology, Blanchette Rockefeller Neurosciences Institute, West Virginia University School of Medicine, Morgantown, West Virginia 26506, USA
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Zarrindast MR, Ebrahimi M, Khalilzadeh A. Influence of ATP-sensitive potassium channels on lithium state-dependent memory of passive avoidance in mice. Eur J Pharmacol 2006; 550:107-11. [PMID: 17022967 DOI: 10.1016/j.ejphar.2006.08.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 08/26/2006] [Accepted: 08/29/2006] [Indexed: 11/29/2022]
Abstract
The effects of ATP-sensitive potassium channels on lithium induced state-dependent memory of passive avoidance task were examined in mice. The pre-training (5 mg/kg) and pre-test (5 mg/kg) injection of lithium impaired memory retrieval on the test day. Impairment of pre-training lithium was restored by pre-test administration of lithium (5 mg/kg), diazoxide, an ATP-sensitive potassium channel opener, (15, 30 and 60 mg/kg) or glibenclamide, an ATP-sensitive potassium channel blocker, (6 and 18 mg/kg). Pre-test administration of inactive doses of lithium (2.5 and 10 mg/kg) plus lower and inactive dose of glibenclamide (2 mg/kg) or diazoxide (1.5 mg/kg) also reversed the amnesia induced by pre-training lithium (5 mg/kg). In conclusion, the ATP-sensitive potassium channel opener or blocker not only mimicked the effect of lithium in state-dependent learning in the absence of lithium on the test day, but also potentiated the effect of low dose of lithium in restoration of memory. Therefore, ATP-sensitive potassium channels may have a modulatory influence on lithium response.
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Affiliation(s)
- Mohammad-Reza Zarrindast
- Department of Pharmacology and Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran.
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Suaudeau C, do-Rego JC, Costentin J. Modifications in avoidance reactions of mice, on a second exposure to the hot plate, resist to various amnesia-inducing treatments. ACTA ACUST UNITED AC 2005; 25:339-47. [PMID: 16051473 DOI: 10.1016/j.cogbrainres.2005.06.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Revised: 06/14/2005] [Accepted: 06/14/2005] [Indexed: 10/25/2022]
Abstract
The avoidance responses of mice exposed to the hot plate (55 degrees C) were found to be modified when tested a second time. In fact, when forepaws licking was no longer observed, the rearing was clearly anticipated (7 s instead of 15 s) as well as jumping (24 s instead of 55 s). These modifications of avoidance strategies as well as their latencies were still observed even 24 days after the first exposure. Avoidance responses were prevented by morphine or haloperidol injected prior to the first exposure, but not with scopolamine or diazepam. These modifications were not affected in mice injected with morphine or submitted to either a supramaximal electroshock or to ether anesthesia delivered immediately after the first hot plate exposure. Among the various known types of memory, these modifications could be linked to procedural memory.
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Affiliation(s)
- Charles Suaudeau
- IFRMP 23, Unité de Neuropsychopharmacologie Expérimentale, CNRS FRE 2735, U.F.R. de Médecine et Pharmacie, 76183 Rouen Cedex, France
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15
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Abstract
The prevalence of dementia is growing in developed countries where elderly patients are increasing in numbers. Neurotransmission modulation is one approach to the treatment of dementia. Cholinergic precursors, anticholinesterases, nicotine receptor agonists and muscarinic M(2) receptor antagonists are agents that enhance cholinergic neurotransmission and that depend on having some intact cholinergic innervation to be effective in the treatment of dementia. The cholinergic precursor choline alfoscerate may be emerging as a potential useful drug in the treatment of dementia, with few adverse effects. Of the anticholinesterases, donepezil, in addition to having a similar efficacy to tacrine in mild-to-moderate Alzheimer's disease (AD), appears to have major advantages; its use is associated with lower drop-out rates in clinical trials, a lower incidence of cholinergic-like side effects and no liver toxicity. Rivastigmine is efficacious in the treatment in dementia with Lewy bodies, a condition in which the other anticholinesterases have not been tested extensively to date. Galantamine is an anticholinesterase and also acts as an allosteric potentiating modulator at nicotinic receptors to increase the release of acetylcholine. Pooled data from clinical trials of patients with mild-to-moderate AD suggest that the benefits and safety profile of galantamine are similar to those of the anticholinesterases. Selective nicotine receptor agonists are being developed that enhance cognitive performance without influencing autonomic and skeletal muscle function, but these have not yet entered clinical trial for dementia. Unlike the cholinergic enhancers, the M(1) receptor agonists do not depend upon intact cholinergic nerves but on intact M(1) receptors for their action, which are mainly preserved in AD and dementia with Lewy bodies. The M(1) receptor-selective agonists developed to date have shown limited efficacy in clinical trials and have a high incidence of side effects. A major recent advancement in the treatment of dementia is memantine, a non-competitive antagonist at NMDA receptors. Memantine is beneficial in the treatment of severe and moderate-to-severe AD and may also be of some benefit in the treatment of mild-to-moderate vascular dementia. Drugs that modulate 5-HT, somatostatin and noradrenergic neurotransmission are also being considered for the treatment of dementia.
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Affiliation(s)
- Sheila A Doggrell
- School of Biomedical Sciences, the University of Queensland, QLD 4072, Australia
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Zhong CB, Pan YP, Tong XY, Xu XH, Wang XL. Delayed rectifier potassium currents and Kv2.1 mRNA increase in hippocampal neurons of scopolamine-induced memory-deficient rats. Neurosci Lett 2005; 373:99-104. [PMID: 15567561 DOI: 10.1016/j.neulet.2004.09.069] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Revised: 09/25/2004] [Accepted: 09/28/2004] [Indexed: 11/22/2022]
Abstract
To explore the ionic mechanisms of memory deficits induced by cholinergic lesion, whole-cell patch clamp recording techniques in combination with single-cell RT-PCR were used to characterize delayed rectifier potassium currents (IK) in acutely isolated hippocampal pyramidal neurons of scopolamine-induced cognitive impairment rats. Scopolamine could induce deficits in spatial memory of rats. The peak amplitude and current density of IK measured in hippocampal pyramidal neurons were increased from 1.2+/-0.6 nA and 38+/-19 pA/pF of the control group (n=12) to 1.8+/-0.5 nA and 62+/-24 pA/pF (n=48, P<0.01) of the scopolamine-treated group. The steady-state activation curve of IK was shifted about 8 mV (P<0.01) in the direction of hyperpolarization in scopolamine-treated rats. The mRNA level of Kv2.1 was increased (P<0.01) in the scopolamine-treated group, but there was no significant change of Kv1.5 mRNA level. The present study demonstrated for the first time that IK was enhanced significantly in hippocampal pyramidal neurons of scopolamine-induced cognitive impairment rats. The increase of Kv2.1 mRNA expression in hippocampal pyramidal cells might be responsible for the enhancement of IK and could be the ionic basis of the memory deficits induced by scopolamine.
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Affiliation(s)
- Chong-Bo Zhong
- Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing 100050, China
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Zarrindast MR, Jafari MR, Shafaghi B, Djahanguiri B. Influence of potassium channel modulators on morphine state-dependent memory of passive avoidance. Behav Pharmacol 2004; 15:103-10. [PMID: 15096910 DOI: 10.1097/00008877-200403000-00002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In a step-down passive avoidance task, the pre-training injection of 1.25-10 mg/kg of morphine impaired memory. This was restored when injection of the same dose of morphine (pre-test treatment) was repeated 24 h later (morphine state-dependent learning: morphine St-D). ATP-dependent potassium (K(ATP)) channels have been reported to be involved in several actions of morphine following mu-receptor stimulation. We have studied the effect of K(ATP) modulators and naloxone in the restoration of memory by morphine in mice. To investigate the part played by cholinergic systems in the effects of a K(ATP) antagonist (glibenclamide) on morphine St-D, we administered low doses of atropine before glibenclamide administration. Locomotor activity was also studied. Naloxone (0.06-1 mg/kg) reversed the effect of pre-test morphine administration. The effects of the K(ATP) channel blocker glibenclamide (2-18 mg/kg) were similar to those of the pre-test administration of morphine. Pre-test co-administration of glibenclamide and morphine showed no potentiation of the morphine effect. Glibenclamide alone or in combination with morphine did not affect locomotor activity. Pre-test administration of different doses of diazoxide (15-60 mg/kg), a K(ATP)-channel opener, had no effect on restoration of memory when used alone or in combination with morphine. In both cases, the locomotor activity was significantly reduced. Diazoxide blocked the effect of glibenclamide on memory recall. Low-dose atropine also prevented glibenclamide enhancement of memory recall, suggesting that this action of glibenclamide is through the cholinergic system.
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Affiliation(s)
- M R Zarrindast
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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18
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Pickering G, Chapuy E, Eschalier A, Dubray C. Memory Impairment Means Less Pain for Mice. Gerontology 2004; 50:152-6. [PMID: 15114036 DOI: 10.1159/000076772] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2003] [Accepted: 07/11/2003] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Clinical observations have reported that individuals with memory deterioration, like in Alzheimer's disease, display a lesser pain sensibility than patients with no cognitive impairment. OBJECTIVE To clarify the link between pain and loss of memory, we studied how memory-impaired mice behave when submitted to hotplate nociceptive tests. METHODS For 5 days (D1-D5), male CD1 mice were injected daily intraperitonealy with saline or scopolamine (s, an anticholinergic drug, 0.2 mg/kg) or ketamine (k, an N-methyl-D-aspartate receptor antagonist (NMDAr), 2.5 mg/kg), at doses leading to memory impairment with no analgesic effect. From D6 to D9, all received saline only. They were placed on the hotplate and removed at the first sign of discomfort, response time being recorded. RESULTS From D1 to D5, reaction time decreased significantly in controls only and did not change in mice with scopolamine or ketamine. From D6 to D9, response times decreased (p < 0.05 (s) and p < 0.0001 (k)) to reach the steady state of control animals. At D5, response time was significantly prolonged for scopolamine (p < 0.01) and ketamine (p < 0.05), compared to controls. CONCLUSION These results show that pain sensibility needs the integrity of the central cholinergic and of the NMDA systems, and that mice with memory impairment display a lesser pain sensibility than normal mice. Further research on the complex interactions of receptors and neurotransmitters involved in pain and cognition could assist in gaining a better understanding of pain and analgesia in patients with memory impairment and in demented individuals.
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Affiliation(s)
- Gisèle Pickering
- INSERM EMI 9904, Clinical Pharmacology Department, University Hospital, Clermont-Ferrand, France.
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19
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Zarrindast MR, Jafari MR, Ahmadi S, Djahanguiri B. Influence of central administration ATP-dependent K+ channel on morphine state-dependent memory of passive avoidance. Eur J Pharmacol 2004; 487:143-8. [PMID: 15033386 DOI: 10.1016/j.ejphar.2004.01.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Accepted: 01/28/2004] [Indexed: 11/29/2022]
Abstract
Pre-training injection of a moderate dose of morphine (5-10 mg/kg) in a step-down passive avoidance task induced state-dependent learning with impaired memory retrieval on the test day. The impairment of memory was restored after the pre-test administration of the same dose of the drug. We have studied the effect of intracerebroventricular administration of naloxone and K(ATP) channel modulators (glibenclamide and diazoxide) on the test day on restoration of memory by morphine in mice. The effect of scopolamine on restoration of memory on the test-day by glibenclamide was studied as well. Naloxone pretreatment (0.006, 0.025 and 0.1 microg/mouse) reversed the effect of pre-test morphine administration. The K(ATP) channel blocker, glibenclamide (0.1, 0.5 and 1 microg/mouse), showed effects similar to those of pre-test administration of morphine. Glibenclamide tended to potentiate the morphine response. Scopolamine (0.15 and 0.30 microg/mouse) prevented the effect of glibenclamide on the restoration of memory. The pre-test administration of different doses of diazoxide (1.7, 5 and 15 microg/mouse), a K(ATP) channel opener, showed no effect on restoration of memory when used alone but decreased morphine state-dependence. Diazoxide blocked the effects of glibenclamide on memory restoration. It is concluded that K(ATP) channel modulators may be involved, at least in part, in morphine state dependence through a cholinergic system mechanism.
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Affiliation(s)
- Mohammad R Zarrindast
- Department of Pharmacology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.
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Tzounopoulos T, Stackman R. Enhancing synaptic plasticity and memory: a role for small-conductance Ca(2+)-activated K+ channels. Neuroscientist 2004; 9:434-9. [PMID: 14678575 DOI: 10.1177/1073858403259282] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Calcium-activated potassium (K+) channels are distributed throughout the central nervous system as well as many other peripheral tissues and comprise three distinct classes of K+ channels: small conductance (SK), intermediate conductance, and large conductance. This update focuses on SK channels. Increases in cytosolic calcium in response to depolarization activate SK channels. Activation of these channels decreases neuronal excitability. In this review, the authors discuss the role of SK channels in the induction of synaptic plasticity and their influence on learning and memory. A testable model that synthesizes the current literature is offered, suggesting that SK channels represent an important regulator of synaptic plasticity and memory.
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Affiliation(s)
- Thanos Tzounopoulos
- Auditory Neuroscience and Department of Behavioral Neuroscience, L-335A, Oregon Hearing Research Center, Oregon Health and Science University, Portland, OR 97239-3098, USA.
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Pan YP, Xu XH, Wang XL. Galantamine blocks delayed rectifier, but not transient outward potassium current in rat dissociated hippocampal pyramidal neurons. Neurosci Lett 2003; 336:37-40. [PMID: 12493597 DOI: 10.1016/s0304-3940(02)01235-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Galantamine is an acetylcholinesterase inhibitor in Alzheimer's disease therapy. In the present study, we investigated the effects of galantamine on delayed rectifier potassium current (I(K(DR))) and transient outward potassium current (I(K(A))) in acutely dissociated rat hippocampal pyramidal neurons by using whole-cell patch clamp technique. I(K(DR)) was inhibited by galantamine in a concentration-dependent manner, while I(K(A)) remained unaffected. The IC(50) value for the blocking action of galantamine on I(K(DR)) was calculated as 2.0 microM. At the concentration of 10 microM, galantamine inhibited I(K(DR)) by 40.2% at +40 mV when depolarized from -50 mV, and shifted the activation curve and inactivation curve of I(K(DR)) to negative potential by -3.8 mV and -11.0 mV, respectively. In conclusion, galantamine potently inhibits I(K(DR)) but not I(K(A)) in rat hippocampal pyramidal neurons.
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Affiliation(s)
- Ya-Ping Pan
- Department of Pharmacology, Institute of Materia Medica, Peking Union Medical College & Chinese Academy of Medical Sciences, 1 Xiannongtan Street, Beijing 100050, China
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Abstract
K(+) channels play critical roles in a wide variety of physiological processes, including the regulation of heart rate, muscle contraction, neurotransmitter release, neuronal excitability, insulin secretion, epithelial electrolyte transport, cell volume regulation, and cell proliferation. As such, K(+) channels have been recognized as potential therapeutic drug targets for many years. Unfortunately, progress toward identifying selective K(+) channel modulators has been severely hampered by the need to use native currents and primary cells in the drug-screening process. Today, however, more than 80 K(+) channel and K(+) channel-related genes have been identified, and an understanding of the molecular composition of many important native K(+) currents has begun to emerge. The identification of these molecular K(+) channel drug targets should lead to the discovery of novel drug candidates. A summary of progress is presented.
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Affiliation(s)
- Alan Wickenden
- Icagen Inc., Suite 460, 4222 Emperor Boulevard, Durham, NC 27703, USA.
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