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de Andrade DML, Correia MC, de Oliveira MG, Santos ESA, Neves BJ, de Paula JR, Rocha ML. Vascular relaxing effect of Hydrocotyle umbellata L. is mediated by blocking of l-type Ca 2+ channels. JOURNAL OF ETHNOPHARMACOLOGY 2022; 289:115019. [PMID: 35074453 DOI: 10.1016/j.jep.2022.115019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/13/2022] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Hydrocotyle umbellata L. is a medicinal herb for the treatment of some health problems including hypertension, according to traditional medicine. Even so, its vascular effects and the pharmacological action mechanisms have not been analyzed. AIM OF THE STUDY This experiment aimed to analyze the effects of hydroalcoholic extract of Hydrocotyle umbellata L. (HEHU) on isolated vessels and verify the interaction of hibalactone (chemical marker) against Cav1.2 channels using molecular docking. MATERIALS AND METHODS Vascular reactivity experiments were performed using rat aortas with (E+) or without endothelium (E-) in an isolated organ bath. Computational molecular docking approaches were used to show the direct effect on L-type Ca2+ Channels. RESULTS HEHU (0-560 μg/mL) induced relaxation of the pre-contracted arteries in a concentration-dependent manner. The maximum effect was higher in E+ (76.8 ± 4.1%) as compared to E- (47.3 ± 5.5%). Pre-treatment of E+ arteries with L-NAME or ODQ reduced the relaxation to similar level of E- arteries. The treatment of arteries with MDL-12,330 A, diclofenac, propranolol and atropine did not change the relaxation induced by HEHU. The contraction caused by internal Ca2+ release induced by caffeine was reduced after HEHU treatment. Moreover, the HEHU also impaired the contraction induced by Ca2+ influx stimulated with phenylephrine or high KCl. The docking study demonstrated the effectiveness of hibalactone in blocking the Cav1.2 channel. CONCLUSIONS These findings show that HEHU induces vascular relaxation which is potentiated (but not dependent) by endothelial cells. Blocking of Ca2+ influx seems to be the main mechanism for the vascular effects of HEHU.
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Affiliation(s)
- Daniela M L de Andrade
- Laboratory of Cardiovascular Pharmacology, Faculty of Pharmacy, Federal University of Goias, Goiania, GO, Brazil.
| | - Mikaelle C Correia
- Laboratory of Cardiovascular Pharmacology, Faculty of Pharmacy, Federal University of Goias, Goiania, GO, Brazil.
| | - Matheus G de Oliveira
- Natural Products Research Laboratory, Faculty of Pharmacy, Federal University of Goias, Goiania, GO, Brazil.
| | - Eder S A Santos
- Laboratory for Molecular Modeling and Drug Design, Faculty of Pharmacy, Federal University of Goias, Goiania, GO, Brazil.
| | - Bruno J Neves
- Laboratory for Molecular Modeling and Drug Design, Faculty of Pharmacy, Federal University of Goias, Goiania, GO, Brazil.
| | - José R de Paula
- Natural Products Research Laboratory, Faculty of Pharmacy, Federal University of Goias, Goiania, GO, Brazil.
| | - Matheus L Rocha
- Laboratory of Cardiovascular Pharmacology, Faculty of Pharmacy, Federal University of Goias, Goiania, GO, Brazil.
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2
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Correia MC, Santos ESA, Neves BJ, Rocha ML. Acetaminophen treatment evokes anticontractile effects in rat aorta by blocking L-type calcium channels. Pharmacol Rep 2022; 74:493-502. [PMID: 35438421 DOI: 10.1007/s43440-022-00367-y] [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: 12/12/2021] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Acetaminophen (APAP) is the most widely used analgesic and antipyretic in the world. However, in high or continuous doses, it can cause serious side effects including blood pressure variability and cardiovascular injuries, which are barely explored. This study aimed to evaluate the acute effect of APAP treatment on vascular tone focused on the blocking of Ca2+ channels. METHODS Rats were treated with APAP orally by gavage (500 mg/kg/single dose). After 12 h, the aorta was isolated for vascular reactivity studies in an isolated organ bath. Vascular contraction and relaxation were measured after different stimuli. Moreover, molecular docking studies were performed to evaluate the action of NAPQI (APAP metabolite) on L-type calcium channels. RESULTS Phenylephrine-induced maximal vascular contraction was reduced in the APAP group (138.4 ± 9.2%) compared to the control group (172.2 ± 11.1%). APAP treatment significantly reduced contraction induced by Ca2+ influx stimulated with phenylephrine or KCl and reduced contraction mediated by Ca2+ released from the sarcoplasmic reticulum induced by caffeine. There was no difference in vascular relaxation induced by acetylcholine or sodium nitroprusside. Computational molecular docking demonstrated that NAPQI is capable of blocking L-type Ca2+ channels (Cav1.2), which would limit the influx of Ca2+. CONCLUSION These results suggest that APAP treatment causes an anticontractile effect in rat aorta, possibly by blocking the influx of Ca2+ through L-type channels (Cav1.2).
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Affiliation(s)
- Mikaelle C Correia
- Laboratory of Pharmacology, UFG, Faculty of Pharmacy, Federal University of Goias, Setor Leste Universitário, CEP, Rua 240, esquina com 5ª Avenida, s/n, Goiânia, GO, 74605-170, Brazil
| | - Eder S A Santos
- LabMol-Laboratory for Molecular Modeling and Drug Design, Faculty of Pharmacy, Federal University of Goias, Rua 240, esquina com 5ª Avenida, s/n, Setor Leste Universitário, Goiânia, GO, 74605-170, Brazil
| | - Bruno J Neves
- LabMol-Laboratory for Molecular Modeling and Drug Design, Faculty of Pharmacy, Federal University of Goias, Rua 240, esquina com 5ª Avenida, s/n, Setor Leste Universitário, Goiânia, GO, 74605-170, Brazil
| | - Matheus L Rocha
- Laboratory of Pharmacology, UFG, Faculty of Pharmacy, Federal University of Goias, Setor Leste Universitário, CEP, Rua 240, esquina com 5ª Avenida, s/n, Goiânia, GO, 74605-170, Brazil.
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3
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McCarthy CG, Wenceslau CF, Ogbi S, Szasz T, Webb RC. Toll-Like Receptor 9-Dependent AMPK α Activation Occurs via TAK1 and Contributes to RhoA/ROCK Signaling and Actin Polymerization in Vascular Smooth Muscle Cells. J Pharmacol Exp Ther 2018; 365:60-71. [PMID: 29348267 DOI: 10.1124/jpet.117.245746] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 01/17/2018] [Indexed: 01/06/2023] Open
Abstract
Traditionally, Toll-like receptor 9 (TLR9) signals through an MyD88-dependent cascade that results in proinflammatory gene transcription. Recently, it was reported that TLR9 also participates in a stress tolerance signaling cascade in nonimmune cells. In this noncanonical pathway, TLR9 binds to and inhibits sarcoplasmic/endoplasmic reticulum Ca2+-ATPase 2 (SERCA2), modulating intracellular calcium handling, and subsequently resulting in the activation of 5'-AMP-activated protein kinase α (AMPKα). We have previously reported that TLR9 causes increased contraction in isolated arteries; however, the mechanisms underlying this vascular dysfunction need to be further clarified. Therefore, we hypothesized that noncanonical TLR9 signaling was also present in vascular smooth muscle cells (VSMCs) and that it mediates enhanced contractile responses through SERCA2 inhibition. To test these hypotheses, aortic microsomes, aortic VSMCs, and isolated arteries from male Sprague-Dawley rats were incubated with vehicle or TLR9 agonist (ODN2395). Despite clear AMPKα activation after treatment with ODN2395, SERCA2 activity was unaffected. Alternatively, ODN2395 caused the phosphorylation of AMPKα via transforming growth factor β-activated kinase 1 (TAK1), a kinase involved in TLR9 inflammatory signaling. Downstream, we hypothesized that that TLR9 activation of AMPKα may be important in mediating actin cytoskeleton reorganization. ODN2395 significantly increased the filamentous-to-globular actin ratio, as well as indices of RhoA/Rho-associated protein kinase (ROCK) activation, with the latter being prevented by AMPKα inhibition. In conclusion, AMPKα phosphorylation after TLR9 activation in VSMCs appears to be an extension of traditional inflammatory signaling via TAK1, as opposed to SERCA2 inhibition and the noncanonical pathway. Nonetheless, TLR9-AMPKα signaling can mediate VSMC function via RhoA/ROCK activation and actin polymerization.
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Affiliation(s)
| | | | - Safia Ogbi
- Department of Physiology, Augusta University, Augusta, Georgia
| | - Theodora Szasz
- Department of Physiology, Augusta University, Augusta, Georgia
| | - R Clinton Webb
- Department of Physiology, Augusta University, Augusta, Georgia
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4
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Schubert R. Relaxation and contraction rates - underestimated parameters of vascular contractility? Acta Physiol (Oxf) 2017; 219:9-10. [PMID: 27683083 DOI: 10.1111/apha.12810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- R. Schubert
- Cardiovascular Physiology; Centre for Biomedicine and Medical Technology Mannheim; Ruprecht-Karls-University Heidelberg; Mannheim Germany
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5
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Abstract
Cyclopiazonic acid (CPA) is an indol-tetramic acid mycotoxin and is produced by the nearly ubiquitous molds, Aspergillus and Penicillium. CPA produced by these molds has been identified in a number of food sources (including, but not limited to, grain, legumes, meat, milk, and cheese) and from parasitic infections of man and other animals. Few incidents of CPA mycotoxicoses have been reported because of the benign nature of the intoxication, the small amounts present, and its effects may be disguised with concurrent aflatoxicosis (some toxicity data may have been generated using aflatoxin-contaminated CPA). CPA is absorbed in the gastrointestinal tract and following oral administration; it has a half-life of approximately 30 hours and is excreted largely unchanged in the urine and feces. Cyclopiazonic acid is not considered to be a potent acute toxin as its oral LD50 in rodents is in the range of 30 to 70 mg/kg. Multiple dose studies also show a range of effects in several species and among mammalian models, the pig appears to be the most sensitive with a no-observable-effect level (NOEL) in the range of 1.0 mg/kg/day. The preponderance of evidence from the rat and other test animals supports this dose as a defensible estimate of a no effect level. The target organs of CPA toxicity appear to be muscle, hepatic tissue, and spleen, with a localization in the former, although a more apparent toxic change in the latter two. The toxicity and symptoms of CPA poisoning can be attributed to its ability to alter normal intracellular calcium flux through its inhibition of the reticular form of the Ca2+-ATPase pump. CPA was not teratogenic in mice. CPA is not considered a carcinogen and the weight of evidence militates against its characterization as a mutagen. Despite CPA-induced pathological changes ascribed to the spleen or bursa of Fabricius, there does not appear to be an effect on the immune system. In vitro studies imply a potential immunomodulatory effect of CPA, but in all of those reports very high concentrations of CPA were required and none of these findings have been supported with in vivo studies. Therefore, based on a NOEL of 1 mg/kg/day and accounting for species variation, an appropriate acceptable daily intake (ADI) would be approximately 10 μg/kg/day or 700 μg/day. In the context of human exposure, if the uppermost limit of CPA found in cheese is 4 μg/g and the average individual consumes 50 g of cheese daily, this allows an intake of 200 μg, less than one third of a traditionally established ADI.
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Affiliation(s)
- G. A. Burdock
- Burdock and Associates, Inc., Vero Beach, Florida, USA
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6
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Lee LK, Kim MY, Kim JH, Lee JU, Park BS, Yang SM, Jeon HJ, Lee WD, Noh JW, Kwak TY, Lee TH, Kim JY, Kim HY, Hwang BY, Kim B, Kim J. A review of deoxycorticosterone acetate-salt hypertension and its relevance for cardiovascular physiotherapy research. J Phys Ther Sci 2015; 27:303-7. [PMID: 25642096 PMCID: PMC4305587 DOI: 10.1589/jpts.27.303] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 07/24/2014] [Indexed: 11/28/2022] Open
Abstract
[Purpose] The purpose of this review was to elucidate the deoxycorticosterone acetate
(DOCA)-salt-related hypertensive mechanism and to contribute to future studies of
cardiovascular physiotherapy. [Methods] This paper focuses on the signal transductions
that control hypertension and its mechanisms. We include results reported by our
laboratory in a literature review. [Results] Our results and the literature show the
various mechanisms of DOCA-salt hypertension. [Conclusion] In this review paper, we
carefully discuss the signal transduction in hypertension based on our studies and with
reference to cardiovascular physiotherapy research.
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Affiliation(s)
- Lim-Kyu Lee
- Laboratory of Health Science and Nanophysiotherapy, Department of Physical Therapy, Graduate School, Yongin University, Republic of Korea
| | - Mee-Young Kim
- Laboratory of Health Science and Nanophysiotherapy, Department of Physical Therapy, Graduate School, Yongin University, Republic of Korea
| | - Ju-Hyun Kim
- Laboratory of Health Science and Nanophysiotherapy, Department of Physical Therapy, Graduate School, Yongin University, Republic of Korea
| | - Jeong-Uk Lee
- Laboratory of Health Science and Nanophysiotherapy, Department of Physical Therapy, Graduate School, Yongin University, Republic of Korea
| | - Byoung-Sun Park
- Laboratory of Health Science and Nanophysiotherapy, Department of Physical Therapy, Graduate School, Yongin University, Republic of Korea
| | - Seung-Min Yang
- Laboratory of Health Science and Nanophysiotherapy, Department of Physical Therapy, Graduate School, Yongin University, Republic of Korea
| | - Hye-Joo Jeon
- Laboratory of Health Science and Nanophysiotherapy, Department of Physical Therapy, Graduate School, Yongin University, Republic of Korea
| | - Won-Deok Lee
- Laboratory of Health Science and Nanophysiotherapy, Department of Physical Therapy, Graduate School, Yongin University, Republic of Korea
| | - Ji-Woong Noh
- Laboratory of Health Science and Nanophysiotherapy, Department of Physical Therapy, Graduate School, Yongin University, Republic of Korea
| | - Taek-Yong Kwak
- Department of Taekwondo Instructor Education, College of Martial Arts, Yongin University, Republic of Korea
| | - Tae-Hyun Lee
- Department of Combative Martial Arts Training, College of Martial Arts, Yongin University, Republic of Korea
| | - Ju-Young Kim
- Department of Combative Martial Arts Training, College of Martial Arts, Yongin University, Republic of Korea
| | - Hye-Young Kim
- Department of Food Science and Nutrition, College of Public Health and Welfare, Yongin University, Republic of Korea
| | - Byong-Yong Hwang
- Department of Physical Therapy, College of Public Health and Welfare, Yongin University: Yongin 449-714, Republic of Korea
| | - Bokyung Kim
- Institute of Functional Genomics, Department of Physiology, School of Medicine, Konkuk University, Republic of Korea
| | - Junghwan Kim
- Department of Physical Therapy, College of Public Health and Welfare, Yongin University: Yongin 449-714, Republic of Korea
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Pereira AC, Olivon VC, Pernomian L, de Oliveira AM. Impairment of α1-adrenoceptor-mediated calcium influx in contralateral carotids following balloon injury: Beneficial effect of superoxide anions. Eur J Pharmacol 2014; 723:397-404. [DOI: 10.1016/j.ejphar.2013.10.066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 10/20/2013] [Accepted: 10/27/2013] [Indexed: 12/29/2022]
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8
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Pereira AC, Olivon VC, de Oliveira AM. Impaired calcium influx despite hyper-reactivity in contralateral carotid following balloon injury: eNOS involvement. Eur J Pharmacol 2010; 642:121-7. [DOI: 10.1016/j.ejphar.2010.05.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 03/25/2010] [Accepted: 05/06/2010] [Indexed: 11/24/2022]
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9
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An Apparent Paradox: Attenuation of Phenylephrine-mediated Calcium Mobilization and Hyperreactivity to Phenylephrine in Contralateral Carotid After Balloon Injury. J Cardiovasc Pharmacol 2010; 56:162-70. [DOI: 10.1097/fjc.0b013e3181e571cd] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Callera GE, Yeh E, Tostes RCA, Caperuto LC, Carvalho CRO, Bendhack LM. Changes in the vascular beta-adrenoceptor-activated signalling pathway in 2Kidney-1Clip hypertensive rats. Br J Pharmacol 2004; 141:1151-8. [PMID: 15006902 PMCID: PMC1574885 DOI: 10.1038/sj.bjp.0705717] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. beta-Adrenoceptor (beta-AR)-mediated vasodilation, which plays an important physiological role in the regulation of vascular tone, is decreased in two-kidney, one clip (2K-1C) renal hypertension. In this study, downstream pathways related to vascular beta-AR activation were evaluated in 2K-1C rats. 2. Relaxation responses to isoprenaline, forskolin and 8-Br-cAMP were diminished in aortas without endothelium from 2K-1C when compared to those in normotensive two kidney (2K). Basal adenosine-3',5'-monophosphate (cAMP), as well as isoprenaline-induced increase in cAMP levels, was not different between 2K and 2K-1C aortas. 3. Contractile responses to caffeine, after depletion and reloading of intracellular Ca(2+) stores, were greater in 2K-1C than in 2K. The presence of isoprenaline during the Ca(2+)-reloading period abolished the differences between groups by increasing caffeine contraction in 2K without changing this response in 2K-1C aortas. Inhibition of the sarcolemmal Ca(2+)ATPase with thapsigargin markedly attenuated isoprenaline vasodilation in both 2K and 2K-1C and abolished the differences between groups. 4. Blockade of ATP-sensitive K(+) channels (K(ATP)) channels with glibenclamide significantly decreased isoprenaline vasodilation in 2K-1C without affecting this response in 2K. Both vascular gene and protein expression of protein kinase A (PKA), as well as phosphoserine-containing proteins, were increased in 2K-1C vs 2K rats. 5. In conclusion, decreased isoprenaline vasodilation in 2K-1C hypertensive rats is related to impaired modulation of the sarcolemmal Ca(2+)ATPase activity. Moreover, K(ATP) channels may play a compensatory role on isoprenaline-induced relaxation in renal hypertension. Both Ca(2+)ATPase and K(ATP) channel functional alterations, associated with decreased beta-AR vasodilation, are paralleled by an upregulation of protein kinase A (PKA) and phosphoserine proteins expression.
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MESH Headings
- 8-Bromo Cyclic Adenosine Monophosphate/pharmacology
- Animals
- Aorta, Thoracic/chemistry
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/pathology
- Caffeine/pharmacology
- Calcium-Transporting ATPases/drug effects
- Calcium-Transporting ATPases/metabolism
- Colforsin/pharmacology
- Cyclic AMP/chemistry
- Cyclic AMP/metabolism
- Cyclic AMP-Dependent Protein Kinases/genetics
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Disease Models, Animal
- Gene Expression/drug effects
- Glyburide/pharmacology
- Hypertension, Renovascular/physiopathology
- Isoproterenol/antagonists & inhibitors
- Isoproterenol/pharmacology
- Kidney/surgery
- Male
- Membrane Proteins/drug effects
- Membrane Proteins/physiology
- Muscle, Smooth, Vascular/chemistry
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Phenylephrine/pharmacology
- Potassium Channels
- RNA, Messenger
- Rats
- Rats, Wistar
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/physiology
- Sarcolemma/drug effects
- Sarcolemma/enzymology
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Thapsigargin/pharmacology
- Vasoconstriction/drug effects
- Vasodilation/drug effects
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Affiliation(s)
- Glaucia E Callera
- Department of Pharmacology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
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11
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David FL, Montezano ACI, Rebouças NA, Nigro D, Fortes ZB, Carvalho MHC, Tostes RCA. Gender differences in vascular expression of endothelin and ET(A)/ET(B) receptors, but not in calcium handling mechanisms, in deoxycorticosterone acetate-salt hypertension. Braz J Med Biol Res 2002; 35:1061-8. [PMID: 12219177 DOI: 10.1590/s0100-879x2002000900006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We determined if the increased vascular responsiveness to endothelin-1 (ET-1) observed in male, but not in female, DOCA-salt rats is associated with differential vascular mRNA expression of ET-1 and/or ET A/ET B receptors or with functional differences in Ca2+ handling mechanisms by vascular myocytes. Uninephrectomized male and female Wistar rats received DOCA and drinking water containing NaCl/KCl. Control rats received vehicle and tap water. Blood pressure and contractile responses of endothelium-denuded aortic rings to agents which induce Ca2+ influx and/or its release from internal stores were measured using standard procedures. Expression of mRNA for ET-1 and ET A/ET B receptors was evaluated by RT-PCR after isolation of total cell RNA from both aorta and mesenteric arteries. Systolic blood pressure was higher in male than in female DOCA rats. Contractions induced by Bay K8644 (which activates Ca2+ influx through voltage-operated L-type channels), and by caffeine, serotonin or ET-1 in Ca2+-free buffer (which reflect Ca2+ release from internal stores) were significantly increased in aortas from male and female DOCA-salt compared to control aortas. DOCA-salt treatment of male, but not female, rats statistically increased vascular mRNA expression of ET-1 and ET B receptors, but decreased the expression of ET A receptors. Molecular up-regulation of vascular ET B receptors, rather than differential changes in smooth muscle Ca2+ handling mechanisms, seems to account for the increased vascular reactivity to ET-1/ET B receptor agonists and higher blood pressure levels observed in male DOCA-salt rats.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
- Animals
- Caffeine/pharmacology
- Calcium/metabolism
- Calcium Channel Agonists/pharmacology
- Desoxycorticosterone
- Endothelin-1/genetics
- Female
- Hypertension/chemically induced
- Hypertension/metabolism
- Hypertension/physiopathology
- Male
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptor, Endothelin A
- Receptor, Endothelin B
- Receptors, Endothelin/genetics
- Receptors, Endothelin/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sex Characteristics
- Vasoconstriction
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Affiliation(s)
- F L David
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
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12
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Callera GE, Bendhack LM. Contribution of sarcoplasmic reticulum calcium uptake and L-type calcium channels to altered vascular responsiveness in the aorta of renal hypertensive rats. GENERAL PHARMACOLOGY 1999; 33:457-66. [PMID: 10647771 DOI: 10.1016/s0306-3623(99)00042-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study examined whether alterations in intracellular or extracellular Ca2+ mobilization were related to differences in caffeine and phenylephrine (PHE)-induced contractions between two-kidney. one-clip hypertensive (2K-1C) and normotensive (2K) rat aortas. After depletion and reloading of intracellular Ca2+ stores, caffeine and PHE-induced contractions in Ca2+-free solution were increased in 2K-1C. Thapsigargin reduced the contraction to caffeine in 2K-1C and 2K with similar sensitivity. PHE-induced contraction in 1.6-mM Ca2+ solution was decreased in 2K-1C, and nifedipine was less effective in lowering this response. The responsiveness to extracellular Ca2+ was decreased in 2K-1C hypertensive rat aortas. Our results indicate an increased intracellular Ca2+ stores that are not related to alteration in Ca2+-ATPase function and a lower contribution of L-type channels to the contraction of 2K-1C aortas.
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Affiliation(s)
- G E Callera
- Laboratory of Pharmacology, College of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, SP, Brazil
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13
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Ceron PI, Bendhack LM. Alterations of calcium uptake in renovascular hypertensive rat aorta: functional assessment with thapsigargin. GENERAL PHARMACOLOGY 1998; 31:265-70. [PMID: 9688470 DOI: 10.1016/s0306-3623(97)00445-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
1. The aim of this study was to test the hypothesis that impaired calcium (Ca2+) recycling by sarcoplasmic reticulum (SR) Ca2+-ATPase takes place in aortae from 1 kidney-1 clip (1K-1C) hypertensive rats. 2. The contractile response elicited when Ca2+ is released from the SR with phenylephrine and caffeine in Ca2+-free Krebs solution was greater in 1K-1C than in 1K rat aorta. In the arteries submitted to intracellular Ca2+ store depletion and reloading, this response was not different between 1K-1C and 1K rat aortae. Thapsigargin decreased the phasic contractile responses to phenylephrine in 1K and 1K-1C rat aortae and increased the tone that developed during the refilling period in 1K-1C rat aortae. 3. Our data support the hypothesis that the 1K-1C rat aorta has defective intracellular Ca2+ regulation that may be implicated in an inadequate SR buffering ability.
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Affiliation(s)
- P I Ceron
- Laboratory of Pharmacology, College of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, Brazil
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14
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Tostes RC, Wilde DW, Bendhack LM, Webb RC. Calcium handling by vascular myocytes in hypertension. Braz J Med Biol Res 1997; 30:315-23. [PMID: 9246229 DOI: 10.1590/s0100-879x1997000300004] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2023] Open
Abstract
Calcium ions (Ca2+) trigger the contraction of vascular myocytes and the level of free intracellular Ca2+ within the myocyte is precisely regulated by sequestration and extrusion mechanisms. Extensive evidence indicates that a defect in the regulation of intracellular Ca2+ plays a role in the augmented vascular reactivity characteristic of clinical and experimental hypertension. For example, arteries from spontaneously hypertensive rats (SHR) have an increased contractile sensitivity to extracellular Ca2+ and intracellular Ca2+ levels are elevated in aortic smooth muscle cells of SHR. We hypothesize that these changes are due to an increase in membrane Ca2+ channel density and possibly function in vascular myocytes from hypertensive animals. Several observations using various experimental approaches support this hypothesis: 1) the contractile activity in response to depolarizing stimuli is increased in arteries from hypertensive animals demonstrating increased voltage-dependent Ca2+ channel activity in hypertension; 2) Ca2+ channel agonists such as Bay K 8644 produce contractions in isolated arterial segments from hypertensive rats and minimal contraction in those from normotensive rats; 3) intracellular Ca2+ concentration is abnormally increased in vascular myocytes from hypertensive animals following treatment with Ca2+ channel agonists and depolarizing interventions, and 4) using the voltage-clamp technique, the inward Ca2+ current in arterial myocytes from hypertensive rats is nearly twice as large as that from myocytes of normotensive rats. We suggest that an alteration in Ca2+ channel function and/or an increase in Ca2+ channel density, resulting from increased channel synthesis or reduced turnover, underlies the increased vascular reactivity characteristic of hypertension.
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Affiliation(s)
- R C Tostes
- Department of Physiology, University of Michigan, Ann Arbor 48109-0622, USA.
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Tostes RC, Wilde DW, Bendhack LM, Webb RC. The effects of cyclopiazonic acid on intracellular Ca2+ in aortic smooth muscle cells from DOCA-hypertensive rats. Braz J Med Biol Res 1997; 30:257-67. [PMID: 9239314 DOI: 10.1590/s0100-879x1997000200016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We tested the hypothesis that cyclopiazonic acid (CPA), an inhibitor of the sarcoplasmic reticulum (SR) Ca(2+)-ATPase, increases intracellular Ca2+ concentration ([Ca2+]) in aortic myocytes and that the increase in [Ca2+]i is higher in aortic cells from deoxycorticosterone acetate (DOCA)-hypertensive rats. Male Sprague-Dawley rats, 250-300 g, underwent uninephrectomy, received a silastic implant containing DOCA (200 mg/kg) and had free access to water supplemented with 1.0% NaCl and 0.2% KCl. Control rats were also uninephrectomized, received normal tap water, but no implant. Intracellular Ca2+ measurements were performed in aortic myocytes isolated from normotensive (Systolic blood pressure = 120 +/- 3 mmHg; body weight = 478 +/- 7 g, N = 7) and DOCA-hypertensive rats (195 +/- 10 mmHg; 358 +/- 16 g, N = 7). The effects of CPA on resting [Ca2+]i and on caffeine-induced increase in [Ca2+]i after [Ca2+]i depletion and reloading were compared in aortic cells from DOCA and normotensive rats. The phasic increase in [Ca2+]i induced by 20 mM caffeine in Ca(2+)-free buffer was significantly higher in DOCA aortic cells (329 +/- 36 nM, N = 5) compared to that in normotensive cells (249 +/- 16 nM, N = 7, P < 0.05). CPA (3 microM) inhibited caffeine-induced increases in [Ca2+]i in both groups. When the cells were placed in normal buffer (1.6 mM Ca2+, loading period), after treatment with Ca(2+)-free buffer (depletion period), an increase in [Ca2+]i was observed in DOCA aortic cells (45 +/- 11 nM, N = 5) while no changes were observed in normotensive cells. CPA (3 microM) potentiated the increase in [Ca2+]i (122 +/- 30 nM, N = 5) observed in DOCA cells during the loading period while only a modest increase in [Ca2+]i (23 +/- 10 nM, N = 5) was observed in normotensive cells. CPA-induced increase in [Ca2+]i did not occur in the absence of extracellular Ca2+ or in the presence of nifedipine. These data show that CPA induces Ca2+ influx in aorta from both normotensive and DOCA-hypertensive rats. However, the increase in [Ca2+]i is higher in DOCA aortic cells possibly due to an impairment in the mechanisms that control [Ca2+]i. The large increase in [Ca2+]i in response to caffeine in DOCA cells probably reflects a greater storage of Ca2+ in the SR.
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Affiliation(s)
- R C Tostes
- Department of Physiology, University of Michigan, Ann Arbor 48109-0622, USA.
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Laurant P, Berthelot A. Endothelin-1-induced contraction in isolated aortae from normotensive and DOCA-salt hypertensive rats: effect of magnesium. Br J Pharmacol 1996; 119:1367-74. [PMID: 8968545 PMCID: PMC1915813 DOI: 10.1111/j.1476-5381.1996.tb16048.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. The contractile responses to endothelin-1 and the effect on these of various magnesium concentrations, were studied in isolated aortic rings from normotensive Sprague-Dawley rats and deoxycorticosterone acetate-salt (DOCA-salt) hypertensive rats. 2. Contractions induced by endothelin-1 were smaller in endothelium-denuded aortae from DOCA-salt hypertensive rats than in those from normotensive rats. The absence of calcium in the medium attenuated endothelin-1-induced contractions of aortae from both normotensive and DOCA-salt rats, but the contraction was greater in aortae from DOCA-salt hypertensive rats. Ryanodine (which inhibits the release of intracellular calcium) inhibited endothelin-1-induced contractions in aortae from DOCA-salt hypertensive rats to a greater extent than in aortae from normotensive rats. 3. A high extracellular magnesium concentration (4.8 mM) attenuated endothelin-1-induced contractions in tissues from DOCA-salt hypertensive rats but not in tissues from normotensive rats. In the absence of calcium, a high concentration of magnesium attenuated endothelin-1-induced contraction in aortae from both normotensive and hypertensive rats. In the presence of ryanodine, a high concentration of magnesium did not modify the contraction in preparations from either strain. 4. Absence of magnesium attenuated endothelin-1-induced contractions in aortae from both normotensive and DOCA-salt hypertensive rats. In the absence of calcium, removal of magnesium totally inhibited endothelin-1-induced contraction in tissues from normotensive rats but had no effect in those from hypertensive rats. In the presence of ryanodine, the lack of magnesium inhibited endothelin-1-induced contractions in aortae from DOCA-salt hypertensive rats but increased the sensitivity to endothelin-1 of aortae from normotensive rats. 5. The presence of endothelium did not modify the effect of high magnesium on endothelin-1-induced contractions in aortae from normotensive and DOCA-salt hypertensive rats. Conversely, the attenuating effect of magnesium removal on endothelin-1-induced contractions did not occur when endothelium was present. 6. In conclusion, endothelin-1-induced contraction was blunted in aortae from DOCA-salt hypertensive rats. The blunted response was related to altered calcium utilization during contraction. Changes in extracellular magnesium concentration differentially alter endothelin-1-induced contraction in aortae from normotensive and hypertensive rats, possibly by interfering with calcium utilization during contraction. Magnesium may be required for the contractile response to endothelin-1 and increasing magnesium may limit the vascular effects of endothelin-1 in blood vessels from DOCA-salt hypertensive rats.
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Affiliation(s)
- P Laurant
- Laboratoire Physiologie, Pharmacologie et Nutrition Préventive Expérimentale, Université de Franche-Comte, Besançon, France
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