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1.
Adv Exp Med Biol ; 1131: 73-91, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31646507

RESUMO

Imaging techniques may overcome the limitations of electrode techniques to measure locally not only membrane potential changes, but also ionic currents. Here, we review a recently developed approach to image native neuronal Ca2+ currents from brain slices. The technique is based on combined fluorescence recordings using low-affinity Ca2+ indicators possibly in combination with voltage sensitive dyes. We illustrate how the kinetics of a Ca2+ current can be estimated from the Ca2+ fluorescence change and locally correlated with the change of membrane potential, calibrated on an absolute scale, from the voltage fluorescence change. We show some representative measurements from the dendrites of CA1 hippocampal pyramidal neurons, from olfactory bulb mitral cells and from cerebellar Purkinje neurons. We discuss the striking difference in data analysis and interpretation between Ca2+ current measurements obtained using classical electrode techniques and the physiological currents obtained using this novel approach. Finally, we show how important is the kinetic information on the native Ca2+ current to explore the potential molecular targets of the Ca2+ flux from each individual Ca2+ channel.


Assuntos
Canais de Cálcio , Neuroimagem , Animais , Cálcio/metabolismo , Canais de Cálcio/fisiologia , Dendritos/fisiologia , Humanos , Potenciais da Membrana/fisiologia , Imagem Óptica , Células Piramidais/fisiologia
2.
Biol Res ; 52(1): 45, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31426853

RESUMO

BACKGROUND: Resveratrol was reported to trigger the apoptosis of fibroblast-like synoviocytes in adjuvant arthritis rats but the subcellular mechanism remains unclear. Since ER stress, mitochondrial dysfunction and oxidative stress were involved in the effects of resveratrol with imbalance of calcium bio-transmission, store operated calcium entry (SOCE), a novel intracellular calcium regulatory pathway, may also participate in this process. RESULTS: In the present study, Resveratrol was found to suppress ORAI1 expression of a dose dependent manner while have no evident effects on STIM1 expressive level. Besides, resveratrol had no effects on ATP or TG induced calcium depletion but present partly dose-dependent suppression of SOCE. On the one hand, microinjection of ORAI1 overexpressed vector in sick toe partly counteracted the therapeutic effects of resveratrol on adjuvant arthritis and serum inflammatory cytokine including IL-1, IL-6, IL-8, IL-10 and TNF-α. On the other hand, ORAI1 SiRNA injection provided slight relief to adjuvant arthritis in rats. In addition, ORAI1 overexpression partly diminished the alleviation of hemogram abnormality induced by adjuvant arthritis after resveratrol treatment while ORAI1 knockdown presented mild resveratrol-like effect on hemogram in rats model. CONCLUSION: These results indicated that resveratrol reduced store-operated Ca2+ entry and enhanced the apoptosis of fibroblast-like synoviocytes in adjuvant arthritis rats model via targeting ORAI1-STIM1 complex, providing a theoretical basis for ORAI1 targeted therapy in future treatment with resveratrol on rheumatoid arthritis.


Assuntos
Apoptose/efeitos dos fármacos , Artrite Experimental/fisiopatologia , Canais de Cálcio/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Proteína ORAI1/efeitos dos fármacos , Resveratrol/farmacologia , Molécula 1 de Interação Estromal/efeitos dos fármacos , Sinoviócitos/efeitos dos fármacos , Animais , Canais de Cálcio/fisiologia , Mitocôndrias/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Resveratrol/administração & dosagem
3.
Adv Exp Med Biol ; 1124: 233-263, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31183830

RESUMO

We start by describing the functions of the uterus, its structure, both gross and fine, innervation and blood supply. It is interesting to note the diversity of the female's reproductive tract between species and to remember it when working with different animal models. Myocytes are the overwhelming cell type of the uterus (>95%) and our focus. Their function is to contract, and they have an intrinsic pacemaker and rhythmicity, which is modified by hormones, stretch, paracrine factors and the extracellular environment. We discuss evidence or not for pacemaker cells in the uterus. We also describe the sarcoplasmic reticulum (SR) in some detail, as it is relevant to calcium signalling and excitability. Ion channels, including store-operated ones, their contributions to excitability and action potentials, are covered. The main pathway to excitation is from depolarisation opening voltage-gated Ca2+ channels. Much of what happens downstream of excitability is common to other smooth muscles, with force depending upon the balance of myosin light kinase and phosphatase. Mechanisms of maintaining Ca2+ balance within the myocytes are discussed. Metabolism, and how it is intertwined with activity, blood flow and pH, is covered. Growth of the myometrium and changes in contractile proteins with pregnancy and parturition are also detailed. We finish with a description of uterine activity and why it is important, covering progression to labour as well as preterm and dysfunctional labours. We conclude by highlighting progress made and where further efforts are required.


Assuntos
Canais de Cálcio/fisiologia , Sinalização do Cálcio , Miométrio/fisiologia , Contração Uterina , Útero/fisiologia , Animais , Cálcio/fisiologia , Feminino , Gravidez , Retículo Sarcoplasmático/fisiologia
4.
Adv Exp Med Biol ; 1124: 357-377, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31183835

RESUMO

The lymphatic system extends its network of vessels throughout most of the body. Lymphatic vessels carry a fluid rich in proteins, immune cells, and long-chain fatty acids known as lymph. It results from an excess of interstitial tissue fluid collected from the periphery and transported centrally against hydrostatic pressure and protein concentration gradients. Thus, this one-way transport system is a key component in the maintenance of normal interstitial tissue fluid volume, protein concentration and fat metabolism, as well as the mounting of adequate immune responses as lymph passes through lymph nodes. In most cases, lymph is actively propelled via rhythmical phasic contractions through a succession of valve-bordered chambers constituting the lymphatic vessels. This contraction/relaxation cycle, or lymphatic pumping, is initiated in the smooth muscle cells present in the vessel wall by a pacemaker mechanism generating voltage-gated Ca2+ channel-induced action potentials. The action potentials provide the depolarization and Ca2+ influx essential for the engagement of the contractile machinery leading to the phasic constrictions of the lymphatic chambers and forward movement of lymph. The spontaneous lymphatic constrictions can be observed in isolated vessels in the absence of any external stimulation, while they are critically regulated by physical means, such as lymph-induced transmural pressure and flow rate, as well as diffusible molecules released from the lymphatic endothelium, perivascular nerve varicosities, blood and surrounding tissues/cells. In this chapter, we describe the latest findings which are improving our understanding of the mechanisms underlying spontaneous lymphatic pumping and discuss current theories about their physiological initiation.


Assuntos
Sinalização do Cálcio , Sistema Linfático/fisiologia , Vasos Linfáticos/fisiologia , Contração Muscular , Potenciais de Ação , Canais de Cálcio/fisiologia , Líquido Extracelular , Humanos , Linfonodos
5.
Bioelectrochemistry ; 128: 155-164, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31003054

RESUMO

In nerve cells, changes in local membrane potentials are generated and propagated along a nerve axon mainly by the function of K+ and Na+ channels. Generally, concurrent monitoring of multi-points on an axon is performed based on the voltage-clamp method. As the respective membrane potentials have been evaluated by considering the relations between the applied potential, the local current, and conductance, experimental values are not directly evaluated. We directly measured the actual membrane potentials and local currents of the respective cells using a nerve-model system comprising liquid-membrane cells. It was then proven that the action potential spreads along the axon toward the axon terminal due to the function of both the channel-type receptors in the synapse and voltage-gated Na+ channels on the axon, and that hyperpolarization cannot be caused by only the operation of the delayed-K+ and the voltage-gated Na+ channels.


Assuntos
Potenciais de Ação , Modelos Neurológicos , Neurônios/fisiologia , Animais , Canais de Cálcio/fisiologia , Transporte de Íons , Potenciais da Membrana , Técnicas de Patch-Clamp , Canais de Potássio/fisiologia , Canais de Potássio de Abertura Dependente da Tensão da Membrana/fisiologia , Sinapses/fisiologia
6.
Science ; 363(6430): 948-955, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30819957

RESUMO

We investigated the roles of components of neuronal synapses for development of the Drosophila air sac primordium (ASP). The ASP, an epithelial tube, extends specialized signaling filopodia called cytonemes that take up signals such as Dpp (Decapentaplegic, a homolog of the vertebrate bone morphogenetic protein) from the wing imaginal disc. Dpp signaling in the ASP was compromised if disc cells lacked Synaptobrevin and Synaptotagmin-1 (which function in vesicle transport at neuronal synapses), the glutamate transporter, and a voltage-gated calcium channel, or if ASP cells lacked Synaptotagmin-4 or the glutamate receptor GluRII. Transient elevations of intracellular calcium in ASP cytonemes correlate with signaling activity. Calcium transients in ASP cells depend on GluRII, are activated by l-glutamate and by stimulation of an optogenetic ion channel expressed in the wing disc, and are inhibited by EGTA and by the GluR inhibitor NASPM (1-naphthylacetyl spermine trihydrochloride). Activation of GluRII is essential but not sufficient for signaling. Cytoneme-mediated signaling is glutamatergic.


Assuntos
Sinalização do Cálcio , Proteínas de Drosophila/fisiologia , Glutamatos/fisiologia , Discos Imaginais/fisiologia , Receptores Ionotrópicos de Glutamato/fisiologia , Sinapses/fisiologia , Animais , Animais Geneticamente Modificados , Canais de Cálcio/fisiologia , Drosophila melanogaster/fisiologia , Imagem Óptica , Pseudópodes/fisiologia , Proteínas R-SNARE/fisiologia , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/fisiologia , Sinaptotagmina I/fisiologia , Técnicas de Cultura de Tecidos
7.
Nat Cell Biol ; 21(4): 476-486, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30858581

RESUMO

The capacity of cells to alter bioenergetics in response to the demands of various biological processes is essential for normal physiology. The coordination of energy sensing and production with highly energy-demanding cellular processes, such as cell division, is poorly understood. Here, we show that a cell cycle-dependent mitochondrial Ca2+ transient connects energy sensing to mitochondrial activity for mitotic progression. The mitochondrial Ca2+ uniporter (MCU) mediates a rapid mitochondrial Ca2+ transient during mitosis. Inhibition of mitochondrial Ca2+ transients via MCU depletion causes spindle checkpoint-dependent mitotic delay. Cellular ATP levels drop during early mitosis, and the mitochondrial Ca2+ transients boost mitochondrial respiration to restore energy homeostasis. This is achieved through mitosis-specific MCU phosphorylation and activation by the mitochondrial translocation of energy sensor AMP-activated protein kinase (AMPK). Our results establish a critical role for AMPK- and MCU-dependent mitochondrial Ca2+ signalling in mitosis and reveal a mechanism of mitochondrial metabolic adaptation to acute cellular energy stress.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Canais de Cálcio/fisiologia , Cálcio/metabolismo , Mitocôndrias/metabolismo , Mitose , Trifosfato de Adenosina/biossíntese , Animais , Canais de Cálcio/genética , Linhagem Celular , Células Cultivadas , Células HeLa , Humanos , Camundongos Endogâmicos C57BL , Microtúbulos/metabolismo , Mitocôndrias/enzimologia
8.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 33(1): 124-128, 2019 01 15.
Artigo em Chinês | MEDLINE | ID: mdl-30644272

RESUMO

Objective: To review the recent progress in the role of thrombospondins (TSPs) in synapse formation in the central nervous system (CNS). Methods: A wide range of domestic and foreign literature on the role of TSPs in the synapse formation of the CNS was reviewed. The role of TSPs in structural features, molecules, and related diseases was reviewed. Results: As an oligosaccharide protein, TSPs play important roles in angiogenesis, inflammation, osteogenesis, cell proliferation, and apoptosis. In the nervous system, they bind to voltage-dependent calcium channels, neuronectin, and other extracellular matrix proteins and cell surface receptors, and participate in and regulate multiple processes such as synapse formation, maturation, and function in the CNS. Conclusion: TSPs as an oligomeric extracellular matrix protein play an important role in the formation of synapses and the repair of synapses after CNS injury.


Assuntos
Canais de Cálcio , Neurogênese , Sinapses , Trombospondinas , Canais de Cálcio/fisiologia , Proliferação de Células
9.
J Ethnopharmacol ; 232: 135-144, 2019 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-30543913

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Citrus reticulatae Pericarpium (Chen pi) was widely used as an important ingredient in the prescription of TCM to treat phlegm fluid retention type hypertension. Since Chen pi is involved in treatment as antihypertensive TCM formula, we have reasonable expectation in believing that it might possess vasorelaxant activity. AIM OF THE STUDY: This study is designed to investigate the vasorelaxant effect of Chen pi and to study its pharmacology effects. MATERIALS AND METHODS: The vasorelaxant effect of water extract of Chen pi (CRW) were evaluated on thoracic aortic rings isolated from Sprague Dawley rats. The fingerprint of Chen pi and the extracts were developed with quantification of hesperidin content by HPTLC. RESULTS: CRW exhibited the strongest vasorelaxant activity. CRW caused the relaxation of the phenylephrine pre-contracted aortic rings in the presence and absence of endothelium as well as in potassium chloride pre-contracted endothelium-intact aortic ring. The incubation of propranolol (ß-adrenergic receptor blocker), atropine (muscarinic receptor blocker), Nω-nitro-L-arginine methyl ester (NO synthase inhibitor), ODQ (sGC inhibitor), indomethacin (COX inhibitor), 4-aminopyridine (KV blocker), barium chloride (Kir blocker), and glibenclamide (KATP blocker) significantly reduced the vasorelaxant effects of CRW. CRW was also found to be active in reducing Ca2+ releases from the sarcoplasmic reticulum and suppressing the voltage-operated calcium channels. CONCLUSION: The vasorelaxant effect of CRW on rat aorta involves NO/sGC, calcium and potassium channels, muscarinic and ß-adrenergic receptors.


Assuntos
Aorta Torácica/efeitos dos fármacos , Citrus , Extratos Vegetais/farmacologia , Vasodilatadores/farmacologia , Animais , Aorta Torácica/fisiologia , Canais de Cálcio/fisiologia , Citrus/química , Técnicas In Vitro , Masculino , Compostos Fitoquímicos/análise , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/química , Canais de Potássio/fisiologia , Ratos Sprague-Dawley , Receptores Adrenérgicos beta/fisiologia , Retículo Sarcoplasmático/efeitos dos fármacos , Retículo Sarcoplasmático/fisiologia , Vasodilatadores/química
10.
Nihon Eiseigaku Zasshi ; 73(3): 269-274, 2018.
Artigo em Japonês | MEDLINE | ID: mdl-30270291

RESUMO

Cadmium is a nonessential heavy metal and an industrial and environmental pollutant. It has been known that cadmium must enter cells to cause damage. To understand the transport systems responsible for cadmium entry into cells, it is important to determine the precise mechanisms underlying cadmium toxicity. Numerous studies have sought to unravel the exact pathways by which cadmium enters various cells and the mechanisms by which it causes toxicity in the organs of human and animals. The purpose of this review is to present the progress made regarding the mechanisms of cadmium transport in various cells and the mechanisms underlying cadmium toxicity in organs.


Assuntos
Cádmio/metabolismo , Cádmio/toxicidade , Poluentes Ambientais/metabolismo , Poluentes Ambientais/toxicidade , Animais , Apoptose , Transporte Biológico , Canais de Cálcio/fisiologia , Proteínas de Transporte/fisiologia , Células/metabolismo , Estresse do Retículo Endoplasmático/fisiologia , Humanos , Metalotioneína/fisiologia , Camundongos , Proteínas Repressoras/fisiologia , Fatores de Transcrição/fisiologia
11.
Biol Pharm Bull ; 41(8): 1127-1134, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30068860

RESUMO

Voltage-gated calcium channels (VGCCs) are classified into high-voltage-activated (HVA) channels and low-voltage-activated channels consisting of Cav3.1-3.3, known as T ("transient")-type VGCC. There is evidence that certain types of HVA channels are involved in neurogenic inflammation and inflammatory pain, in agreement with reports indicating the therapeutic effectiveness of gabapentinoids, ligands for the α2δ subunit of HVA, in treating not only neuropathic, but also inflammatory, pain. Among the Cav3 family members, Cav3.2 is abundantly expressed in the primary afferents, regulating both neuronal excitability at the peripheral terminals and spontaneous neurotransmitter release at the spinal terminals. The function and expression of Cav3.2 are modulated by a variety of inflammatory mediators including prostanoids and hydrogen sulfide (H2S), a gasotransmitter. The increased activity of Cav3.2 by H2S participates in colonic, bladder and pancreatic pain, and regulates visceral inflammation. Together, VGCCs are involved in inflammation and inflammatory pain, and Cav3.2 T-type VGCC is especially a promising therapeutic target for the treatment of visceral inflammatory pain in patients with irritable bowel syndrome, interstitial cystitis/bladder pain syndrome, pancreatitis, etc., in addition to neuropathic pain.


Assuntos
Canais de Cálcio/fisiologia , Inflamação/fisiopatologia , Dor/fisiopatologia , Animais , Humanos
12.
Skelet Muscle ; 8(1): 22, 2018 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-30025545

RESUMO

The process by which muscle fiber electrical depolarization is linked to activation of muscle contraction is known as excitation-contraction coupling (ECC). Our understanding of ECC has increased enormously since the early scientific descriptions of the phenomenon of electrical activation of muscle contraction by Galvani that date back to the end of the eighteenth century. Major advances in electrical and optical measurements, including muscle fiber voltage clamp to reveal membrane electrical properties, in conjunction with the development of electron microscopy to unveil structural details provided an elegant view of ECC in skeletal muscle during the last century. This surge of knowledge on structural and biophysical aspects of the skeletal muscle was followed by breakthroughs in biochemistry and molecular biology, which allowed for the isolation, purification, and DNA sequencing of the muscle fiber membrane calcium channel/transverse tubule (TT) membrane voltage sensor (Cav1.1) for ECC and of the muscle ryanodine receptor/sarcoplasmic reticulum Ca2+ release channel (RyR1), two essential players of ECC in skeletal muscle. In regard to the process of voltage sensing for controlling calcium release, numerous studies support the concept that the TT Cav1.1 channel is the voltage sensor for ECC, as well as also being a Ca2+ channel in the TT membrane. In this review, we present early and recent findings that support and define the role of Cav1.1 as a voltage sensor for ECC.


Assuntos
Acoplamento Excitação-Contração/fisiologia , Músculo Esquelético/fisiologia , Regulação Alostérica/fisiologia , Animais , Canais de Cálcio/fisiologia , Caveolina 1/química , Caveolina 1/fisiologia , Humanos , Potenciais da Membrana/fisiologia , Estrutura Molecular , Contração Muscular/fisiologia , Fibras Musculares Esqueléticas/fisiologia , Canal de Liberação de Cálcio do Receptor de Rianodina/química , Canal de Liberação de Cálcio do Receptor de Rianodina/fisiologia
13.
Bull Exp Biol Med ; 165(2): 272-275, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29923011

RESUMO

Store-operated channels activated in response to intracellular calcium store depletion represent the main pathway of calcium entry from the extracellular space in nonelectroexcitable cells. Adapter proteins organize the components of this system into integral complex. We studied the influence of adapter proteins of the Homer family on endogenous store-operated calcium Imin channels in A431 cells. Monomeric Homer 1a proteins increase activity of Imin channels, but did not modulate their electrophysiological properties. Recombinant Homer 1c protein did not block the induced calcium currents.


Assuntos
Canais de Cálcio/metabolismo , Cálcio/metabolismo , Proteínas de Arcabouço Homer/fisiologia , Potenciais de Ação/efeitos dos fármacos , Agonistas dos Canais de Cálcio/metabolismo , Agonistas dos Canais de Cálcio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Canais de Cálcio/fisiologia , Sinalização do Cálcio/efeitos dos fármacos , Citoplasma/metabolismo , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Proteínas de Arcabouço Homer/farmacologia , Humanos , Ativação do Canal Iônico/efeitos dos fármacos , Técnicas de Patch-Clamp , Multimerização Proteica/fisiologia , Proteínas Recombinantes/farmacologia , Células Tumorais Cultivadas
14.
Pestic Biochem Physiol ; 148: 190-198, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29891372

RESUMO

Pyrethroid insecticides modify the gating of voltage-gated sodium channels, thus disrupting the function of the nervous system. In Drosophila melanogaster, para encodes a functional sodium channel. Drosophila Sodium Channel 1 (DSC1), although considered as a putative sodium channel gene for decades due to its high sequence similarity with sodium channels, encodes a voltage-gated cation channel with high permeability to Ca2+. Previous study showed that knockout of the DSC1 gene (DSC1-/-) caused Drosophila adults to be more susceptible to pyrethroids and the adult giant fiber (GF) neural circuit were more susceptible to pyrethroids. Considering distinct expression of DSC1 transcripts in adults and larvae, we examined the role of DSC1 channels in regulating pyrethroid susceptibility in Drosophila larvae. We conducted insecticide bioassays and examined the susceptibility of the larval neuromuscular junction (NMJ) to pyrethroids using w1118, an insecticide-susceptible line, DSC1-/-, parats1 (a pyrethroid-resistant line carrying a mutation in para) and a double mutation line parats1; DSC1-/-. We found that, like the adult GF system, the NMJ of DSC1-/- flies is more susceptible to pyrethroids than that of w1118 with the pyrethroid susceptibility ranked as DSC1-/- > w1118 > parats1; DSC1-/- > parats1. However, DSC1-/- larvae were about two-fold more resistant to pyrethroids than w1118 larvae, and the pyrethroid susceptibility of larvae ranked as w1118 > DSC1-/- > parats1; DSC1-/- > parats1. These results reveal common and distinct roles of DSC1 channels in regulating the action of pyrethroids in adults and larvae of D. melanogaster.


Assuntos
Canais de Cálcio/fisiologia , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/efeitos dos fármacos , Resistência a Inseticidas/genética , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Piretrinas/toxicidade , Animais , Bioensaio , Canais de Cálcio/genética , Canais de Cálcio/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Mutação , Junção Neuromuscular/efeitos dos fármacos , Ligação Proteica , Canais de Sódio Disparados por Voltagem/metabolismo
15.
J. physiol. biochem ; 74(2): 207-221, mayo 2018. graf, tab
Artigo em Inglês | IBECS | ID: ibc-178978

RESUMO

The dissociated dorsal root ganglion (DRG) neurons with or without culture were widely used for investigation of their electrophysiological properties. The culture procedures, however, may alter the properties of these neurons and the effects are not clear. In the present study, we recorded the action potentials (AP) and the voltage-gated Na+, K+, and Ca2+ currents with patch clamp technique and measured the mRNA of Nav1.6-1.9 and Cav2.1–2.2 with real-time PCR technique from acutely dissociated and 1-day (1-d) cultured DRG neurons. The effects of the nerve growth factor (NGF) on the expression of Nav1.6-1.9 and Cav2.1–2.2 were evaluated. The neurons were classified as small (DRG-S), medium (DRG-M), and large (DRG-L), according to their size frequency distribution pattern. We found 1-d culture increased the AP size but reduced the excitability, and reduced the voltage-gated Na+ and Ca2+ currents and their corresponding mRNA expression in all types of neurons. The lack of NGF in the culture medium may contribute to the reduced Na+ and Ca2+ current, as the application of NGF recovered some of the reduced transcripts (Nav1.9, Cav2.1, and Cav2.2). 1-d culture showed neuron-type specific effects on some of the AP properties: it increased the maximum AP depolarizing rate (MDR) and hyperpolarized the resting membrane potential (RP) in DRG-M and DRG-L neurons, but slowed the maximum AP repolarizing rate (MRR) in DRG-S neurons. In conclusion, the 1-d cultured neurons had different properties with those of the acutely dissociated neurons, and lack of NGF may contribute to some of these differences


No disponible


Assuntos
Animais , Feminino , Ratos , Gânglios Espinais/citologia , Gânglios Espinais/fisiologia , Neurônios/fisiologia , Potenciais de Ação , Canais de Cálcio/genética , Canais de Cálcio/fisiologia , Células Cultivadas , Fator de Crescimento Neural , Técnicas de Patch-Clamp , Canais de Potássio de Abertura Dependente da Tensão da Membrana/genética , Canais de Potássio de Abertura Dependente da Tensão da Membrana/fisiologia , RNA Mensageiro/genética , Ratos Sprague-Dawley
16.
J Pharmacol Sci ; 137(1): 55-60, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29703643

RESUMO

The heart of the medaka, a small fish native to East Asia, has electrophysiological aspects similar to mammalian hearts. We found that the heart rates of medaka were more similar to humans than mice or rats. Medaka exhibited similar electrocardiogram patterns to those of humans, suggesting a similarity in cardiac impulse formation and propagation. Their hearts also exhibited similar responsiveness to verapamil, a calcium channel antagonist; atropine, a parasympathetic nerve blocker; propranolol, a sympathetic ß-adrenergic blocker; and isoproterenol, a sympathetic ß-adrenergic agonist. We successfully analyzed action potentials and cardiac contractile forces in vivo. Verapamil affected action potential duration and reduced heart rate, suggesting the importance of voltage-dependent calcium channels in determining the heart rhythm of medaka. We also analyzed the expression of the voltage-dependent calcium channel ß2 subunit, which participates in channel formation in cardiac myocytes, and found that splice variant type-2 was the only major transcript in the heart. Our results indicate that medaka could be an appropriate animal model for studying cardiovascular pharmacology.


Assuntos
Potenciais de Ação/efeitos dos fármacos , Bloqueadores dos Canais de Cálcio/farmacologia , Eletrocardiografia/efeitos dos fármacos , Modelos Animais , Oryzias , Verapamil/farmacologia , Animais , Canais de Cálcio/metabolismo , Canais de Cálcio/fisiologia , Células Cultivadas , Frequência Cardíaca/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos
17.
PLoS One ; 13(4): e0194980, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29694371

RESUMO

Voltage-dependent inward currents responsible for the depolarizing phase of action potentials were characterized in smooth muscle cells of 4th order arterioles in mouse skeletal muscle. Currents through L-type Ca2+ channels were expected to be dominant; however, action potentials were not eliminated in nominally Ca2+-free bathing solution or by addition of L-type Ca2+ channel blocker nifedipine (10 µM). Instead, Na+ channel blocker tetrodotoxin (TTX, 1 µM) reduced the maximal velocity of the upstroke at low, but not at normal (2 mM), Ca2+ in the bath. The magnitude of TTX-sensitive currents recorded with 140 mM Na+ was about 20 pA/pF. TTX-sensitive currents decreased five-fold when Ca2+ increased from 2 to 10 mM. The currents reduced three-fold in the presence of 10 mM caffeine, but remained unaltered by 1 mM of isobutylmethylxanthine (IBMX). In addition to L-type Ca2+ currents (15 pA/pF in 20 mM Ca2+), we also found Ca2+ currents that are resistant to 10 µM nifedipine (5 pA/pF in 20 mM Ca2+). Based on their biophysical properties, these Ca2+ currents are likely to be through voltage-gated T-type Ca2+ channels. Our results suggest that Na+ and at least two types (T- and L-) of Ca2+ voltage-gated channels contribute to depolarization of smooth muscle cells in skeletal muscle arterioles. Voltage-gated Na+ channels appear to be under a tight control by Ca2+ signaling.


Assuntos
Potenciais de Ação , Arteríolas/citologia , Arteríolas/fisiologia , Músculo Liso Vascular/citologia , Músculo Liso Vascular/fisiologia , Miócitos de Músculo Liso/metabolismo , Canais de Ânion Dependentes de Voltagem/metabolismo , Animais , Cálcio/metabolismo , Canais de Cálcio/fisiologia , Fenômenos Eletrofisiológicos , Camundongos , Sódio/metabolismo , Canais de Sódio/fisiologia
18.
Eur J Pharmacol ; 826: 9-16, 2018 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-29458039

RESUMO

Our previous studies have shown that α1-adrenoceptors, in addition to α2-adrenoceptors, are involved in enhanced contraction of cutaneous blood vessels during cooling. The present study aimed to elucidate the mechanism underlying it. In tail and iliac arteries isolated from rats, isometric contraction was measured using a myograph and the phosphorylation level of myosin phosphatase target subunit 1 (MYPT1) was quantified by western blotting. The phenylephrine-induced contraction was enhanced by cooling to 24 °C in tail arteries, but was suppressed in iliac arteries. Endothelium denudation or treatment with iberiotoxin enhanced the phenylephrine-induced contraction in tail arteries at 37 °C; however, neither affected the contraction at 24 °C. The phenylephrine-induced contraction at 37 °C was largely suppressed by nifedipine in iliac arteries, but only slightly in tail arteries. The Rho kinase inhibitor H-1152 largely suppressed the phenylephrine-induced contraction at 24 °C, but only slightly at 37 °C, in both arteries. The phosphorylation level of MYPT1 at Thr855 in tail arteries was increased by the cooling. Taken together, these results suggest the following mechanism in regard to cooling-induced enhancement of α1-adrenoceptor-mediated contraction in tail arteries: Cooling enhances the contraction of tail arteries via α1-adrenoceptor stimulation by reducing endothelium-dependent, large-conductance Ca2+-activated K+ channel-mediated relaxation and by inducing Rho kinase-mediated Ca2+ sensitization, although the latter occurs even in iliac arteries. A smaller contribution of voltage-dependent Ca2+ channels, which are largely suppressed by cooling, to α1-adrenoceptor-mediated contraction in tail arteries seems to be more crucially involved in the appearance of the enhanced contractile response to cooling.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Canais de Cálcio/fisiologia , Temperatura Baixa/efeitos adversos , Receptores Adrenérgicos alfa 1/fisiologia , Vasoconstrição/fisiologia , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/análogos & derivados , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/farmacologia , Animais , Cálcio/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Artéria Ilíaca/fisiologia , Canais de Potássio Ativados por Cálcio de Condutância Alta , Masculino , Modelos Animais , Contração Muscular/efeitos dos fármacos , Contração Muscular/fisiologia , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/fisiologia , Nifedipino/farmacologia , Fenilefrina/farmacologia , Fosforilação , Proteína Fosfatase 1/metabolismo , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Quinases Associadas a rho/antagonistas & inibidores
19.
Gene ; 654: 95-102, 2018 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-29408621

RESUMO

PURPOSE: The present study aimed to elucidate the pathogenesis of colon cancer and identify genes associated with tumor development. METHODS: Three datasets, two (GSE74602 and GSE44861) from the Gene Expression Omnibus database and RNA-Seq colon cancer data from The Cancer Genome Atlas data portal, were downloaded. These three datasets were grouped using a meta-analysis approach, and differentially expressed genes (DEGs) were identified between colon tumor samples and adjacent normal samples. Functional enrichment analysis and regulatory factor predication were performed for significant genes. Additionally, small-molecule drugs associated with colon cancer were predicted, and a prognostic risk model was constructed. RESULTS: There were 251 overlapping DEGs (135 up- and 116 downregulated) between cancer samples and control samples in the three datasets. The DEGs were mainly involved in protein transport and apoptotic and neurotrophin signaling pathways. A total of 70 small-molecule drugs were predicated to be associated with colon cancer. Additionally, in the miRNA-target regulatory network, we found that SLC44A1 can be targeted by hsa-miR-183, hsa-miR-206, and hsa-miR-147, while KLF13 can be regulated by hsa-miR-182, hsa-miR-206, and hsa-miR-153. Moreover, the results of the prognostic risk model showed that four genes (VAMP1, P2RX5, CACNB1, and CRY2) could divide the samples into high and low risk groups. CONCLUSION: SLC44A1 and KLF13 may be involved in tumorigenesis and the metastasis of colon cancer by miRNA regulation. In addition, a four-gene (VAMP1, P2RX5, CACNB1, and CRY2) expression signature may have prognostic and predictive value in colon cancer.


Assuntos
Antígenos CD/fisiologia , Proteínas de Ciclo Celular/fisiologia , Neoplasias do Colo/metabolismo , Perfilação da Expressão Gênica , Fatores de Transcrição Kruppel-Like/fisiologia , MicroRNAs/genética , Proteínas de Transporte de Cátions Orgânicos/fisiologia , Proteínas Repressoras/fisiologia , Antígenos CD/genética , Canais de Cálcio/genética , Canais de Cálcio/fisiologia , Carcinogênese , Proteínas de Ciclo Celular/genética , Neoplasias do Colo/genética , Criptocromos/genética , Criptocromos/fisiologia , Bases de Dados Factuais , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Humanos , Fatores de Transcrição Kruppel-Like/genética , Metástase Neoplásica , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas de Transporte de Cátions Orgânicos/genética , Prognóstico , Receptores Purinérgicos P2X5/genética , Receptores Purinérgicos P2X5/fisiologia , Proteínas Repressoras/genética , Risco , Proteína 1 Associada à Membrana da Vesícula/genética , Proteína 1 Associada à Membrana da Vesícula/fisiologia
20.
Neurosci Res ; 127: 33-44, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29317246

RESUMO

At the presynaptic terminal, neuronal firing activity induces membrane depolarization and subsequent Ca2+ entry through voltage-gated Ca2+ (CaV) channels triggers neurotransmitter release from the active zone. Presynaptic Ca2+ channels form a large signaling complex, which targets synaptic vesicles to Ca2+ channels for efficient release and mediates Ca2+ channel regulation. The presynaptic CaV2 channel family (comprising CaV2.1, CaV2.2 and CaV2.3 isoforms) encode the pore-forming α1 subunit. The cytoplasmic regions are the target of regulatory proteins for channel modulation. Modulation of presynaptic Ca2+ channels has a powerful influence on synaptic transmission. This article overviews spatial and temporal regulation of Ca2+ channels by effectors and sensors of Ca2+ signaling, and describes the emerging evidence for a critical role of Ca2+ channel regulation in control of synaptic transmission and presynaptic plasticity. Sympathetic superior cervical ganglion neurons in culture expressing CaV2.2 channels represent a well-characterized system for investigating synaptic transmission. The exogenously expressed α1 subunit of the CaV2.1 as well as endogenous CaV2.2 was examined for modulation of channel activity, and thereby regulation of synaptic transmission. The constitutive and Ca2+-dependent modulation of CaV2.1 channels coordinately act as spatial and temporal molecular switches to control synaptic efficacy.


Assuntos
Canais de Cálcio/fisiologia , Neurônios/citologia , Terminações Pré-Sinápticas/metabolismo , Animais , Cálcio/metabolismo , Humanos , Modelos Moleculares , Transmissão Sináptica/fisiologia
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