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Kwok ACM, Chan WS, Wong JTY. Dinoflagellate Amphiesmal Dynamics: Cell Wall Deposition with Ecdysis and Cellular Growth. Mar Drugs 2023; 21:md21020070. [PMID: 36827111 PMCID: PMC9959387 DOI: 10.3390/md21020070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/11/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
Dinoflagellates are a major aquatic protist group with amphiesma, multiple cortical membranous "cell wall" layers that contain large circum-cortical alveolar sacs (AVs). AVs undergo extensive remodeling during cell- and life-cycle transitions, including ecdysal cysts (ECs) and resting cysts that are important in some harmful algal bloom initiation-termination. AVs are large cortical vesicular compartments, within which are elaborate cellulosic thecal plates (CTPs), in thecate species, and the pellicular layer (PL). AV-CTPs provide cellular mechanical protection and are targets of vesicular transport that are replaced during EC-swarmer cell transition, or with increased deposition during the cellular growth cycle. AV-PL exhibits dynamical-replacement with vesicular trafficking that are orchestrated with amphiesmal chlortetracycline-labeled Ca2+ stores signaling, integrating cellular growth with different modes of cell division cycle/progression. We reviewed the dynamics of amphiesma during different cell division cycle modes and life cycle stages, and its multifaceted regulations, focusing on the regulatory and functional readouts, including the coral-zooxanthellae interactions.
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González-Jamett A, Maldifassi MC, Cárdenas AM. Isolation and Purification of Chromaffin Granules from Adrenal Glands and Cultured Neuroendocrine Cells. Methods Mol Biol 2023; 2565:283-296. [PMID: 36205901 DOI: 10.1007/978-1-0716-2671-9_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Chromaffin granules isolated from adrenal glands constitute a powerful experimental tool to the study of secretory vesicle components and their participation in fusion and docking processes, vesicle aggregation, and interactions with cytosolic components. Although it is possible to isolate and purify chromaffin granules from adrenal glands of different species, bovine adrenal glands are the most used tissue source due to its easy handling and the large amount of granules that can be obtained from this tissue. In this chapter, we describe an easy-to-use and short-term protocol for efficiently obtaining highly purified chromaffin granules from bovine adrenal medulla. We additionally include protocols to isolate granules from cultured bovine chromaffin cells and PC12 cells, as well as a section to obtain chromaffin granules from mouse adrenal glands.
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Affiliation(s)
- Arlek González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso, Chile
| | - María Constanza Maldifassi
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Ana María Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
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Zhang C, Feng Y, Balutowski A, Miner GE, Rivera-Kohr DA, Hrabak MR, Sullivan KD, Guo A, Calderin JD, Fratti RA. The interdependent transport of yeast vacuole Ca 2+ and H + and the role of phosphatidylinositol 3,5-bisphosphate. J Biol Chem 2022; 298:102672. [PMID: 36334632 PMCID: PMC9706634 DOI: 10.1016/j.jbc.2022.102672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/30/2022] [Accepted: 10/31/2022] [Indexed: 11/27/2022] Open
Abstract
Yeast vacuoles are acidified by the v-type H+-ATPase (V-ATPase) that is comprised of the membrane embedded VO complex and the soluble cytoplasmic V1 complex. The assembly of the V1-VO holoenzyme on the vacuole is stabilized in part through interactions between the VO a-subunit ortholog Vph1 and the lipid phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2). PI(3,5)P2 also affects vacuolar Ca2+ release through the channel Yvc1 and uptake through the Ca2+ pump Pmc1. Here, we asked if H+ and Ca2+ transport activities were connected through PI(3,5)P2. We found that overproduction of PI(3,5)P2 by the hyperactive fab1T2250A mutant augmented vacuole acidification, whereas the kinase-inactive fab1EEE mutant attenuated the formation of a H+ gradient. Separately, we tested the effects of excess Ca2+ on vacuole acidification. Adding micromolar Ca2+ blocked vacuole acidification, whereas chelating Ca2+ accelerated acidification. The effect of adding Ca2+ on acidification was eliminated when the Ca2+/H+ antiporter Vcx1 was absent, indicating that the vacuolar H+ gradient can collapse during Ca2+ stress through Vcx1 activity. This, however, was independent of PI(3,5)P2, suggesting that PI(3,5)P2 plays a role in submicromolar Ca2+ flux but not under Ca2+ shock. To see if the link between Ca2+ and H+ transport was bidirectional, we examined Ca2+ transport when vacuole acidification was inhibited. We found that Ca2+ transport was inhibited by halting V-ATPase activity with Bafilomycin or neutralizing vacuolar pH with chloroquine. Together, these data show that Ca2+ transport and V-ATPase efficacy are connected but not necessarily through PI(3,5)P2.
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Affiliation(s)
- Chi Zhang
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Yilin Feng
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Adam Balutowski
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Gregory E Miner
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - David A Rivera-Kohr
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Michael R Hrabak
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Katherine D Sullivan
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Annie Guo
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Jorge D Calderin
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Rutilio A Fratti
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA; Center for Biophysics & Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
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Verma P, Mohanty N, Pruseth B, Sahoo S, Katiyar A, Singh H, Jena SK, Das RR, Som TK, Sahoo SK, Nanda P, Ghosh A. Identification of Candidate Immune System MicroRNAs Differentially Found in Colostrum and Milk Exosomes. Microrna 2022; 11:216-226. [PMID: 35786199 DOI: 10.2174/2211536611666220630102316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 04/01/2022] [Accepted: 04/13/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The fetus grows in a sterile womb environment. After birth, the newborn immune system has two immediate hurdles to clear. First immediate suppression of the womb compatible immune system and turn on the immune system of the newborn that can counter the antigenic world. The underlying mechanism of immune fluctuation by milk microRNAs (miRNAs) can be crucial for the treatment of critical or premature newborn. METHODS We collected fourteen samples of each colostrum and mature milk from lactating mothers, four samples of each were used for microarray analysis, and the other ten were used for miRNA expression profiling by real-time PCR. RESULTS From the microarray, 154 differentially expressed miRNAs were identified, whereas 49 miRNAs were revealed as immune-related miRNAs based on a literature study. Among the 49 miRNAs, 33 were already shown as strongly validated immune-related miRNAs (validated by qPCR, Western Blot, and Luciferase assay) and were considered for further analysis. Twenty-two miRNA expressions were analysed by real-time PCR as their Ct values were within considerable limits. Twelve numbers of miRNAs were significantly downregulated in mature milk compared to colostrum, which were again subjected to bioinformatics analysis to predict the biological mechanisms behind the differentially expressed miRNAs. CONCLUSION This study shed light on the human milk exosome miRNA expression dynamics during lactation and their possible role in the gradual skewing of the newborns' immune system. The information is crucial for the development and onset of sepsis in premature newborns in the NICU.
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Affiliation(s)
- Poonam Verma
- Department of Physiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha 751019, India
| | - Niharika Mohanty
- Department of Physiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha 751019, India
| | - Babita Pruseth
- Department of Physiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha 751019, India
| | - Sonali Sahoo
- Department of Physiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha 751019, India
| | - Amit Katiyar
- ICMR-AIIMS Computational Genomics Centre, Division of Biomedical Informatics, Indian Council of Medical Research, Ansari Nagar, New Delhi-110029, India
| | - Harpreet Singh
- ICMR-AIIMS Computational Genomics Centre, Division of Biomedical Informatics, Indian Council of Medical Research, Ansari Nagar, New Delhi-110029, India
| | - Saubhagya Kumar Jena
- Department of Obstetrics & Gynaecology, All India Institute of Medical Sciences, Bhubaneswar, Odisha 751019, India
| | - Rashmi Ranjan Das
- Department of Paediatrics, All India Institute of Medical Sciences, Bhubaneswar, Odisha 751019, India
| | - Tapas Kumar Som
- Department of Neonatology, All India Institute of Medical Sciences, Bhubaneswar, Odisha 751019, India
| | | | - Pranati Nanda
- Department of Physiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha 751019, India
| | - Amit Ghosh
- Department of Physiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha 751019, India
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Holler JG, Slotved HC, Mølgaard P, Olsen CE, Christensen SB. Chalcone inhibitors of the NorA efflux pump in Staphylococcus aureus whole cells and enriched everted membrane vesicles. Bioorg Med Chem 2012; 20:4514-21. [PMID: 22682300 DOI: 10.1016/j.bmc.2012.05.025] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/01/2012] [Accepted: 05/11/2012] [Indexed: 11/19/2022]
Abstract
A library of 117 chalcones was screened for efflux pump inhibitory (EPI) activity against NorA mediated ethidium bromide efflux. Five of the chalcones (5-7, 9, and 10) were active and two chalcones (9 and 10) were equipotent to reserpine with IC(50)-values of 9.0 and 7.7 μM, respectively. Twenty chalcones were subsequently proved to be inhibitors of the NorA efflux pump in everted membrane vesicles. Compounds 5, 7, and 9 synergistically increased the effect of ciprofloxacin on Staphylococcus aureus. Our results suggest that chalcones might be developed into drugs for overcoming multidrug resistance based on efflux transporters of microorganisms.
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Affiliation(s)
- Jes Gitz Holler
- University of Copenhagen, Faculty of Pharmaceutical Sciences, Department of Medicinal Chemistry, Denmark.
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Holler JG, Christensen SB, Slotved HC, Rasmussen HB, Gúzman A, Olsen CE, Petersen B, Mølgaard P. Novel inhibitory activity of the Staphylococcus aureus NorA efflux pump by a kaempferol rhamnoside isolated from Persea lingue Nees. J Antimicrob Chemother 2012; 67:1138-44. [PMID: 22311936 DOI: 10.1093/jac/dks005] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVES To isolate a plant-derived compound with efflux inhibitory activity towards the NorA transporter of Staphylococcus aureus. METHODS Bioassay-guided isolation was used, with inhibition of ethidium bromide efflux via NorA as a guide. Characterization of activity was carried out using MIC determination and potentiation studies of a fluoroquinolone antibiotic in combination with the isolated compound. Everted membrane vesicles of Escherichia coli cells enriched with NorA were prepared to study efflux inhibitory activity in an isolated manner. RESULTS The ethanolic extract of Persea lingue was subjected to bioassay-guided fractionation and led to the isolation of the known compound kaempferol-3-O-α-L-(2,4-bis-E-p-coumaroyl)rhamnoside (compound 1). Evaluation of the dose-response relationship of compound 1 showed that ethidium bromide efflux was inhibited, with an IC(50) value of 2 μM. The positive control, reserpine, was found to have an IC(50) value of 9 μM. Compound 1 also inhibited NorA in enriched everted membrane vesicles of E. coli. Potentiation studies revealed that compound 1 at 1.56 mg/L synergistically increased the antimicrobial activity of ciprofloxacin 8-fold against a NorA overexpresser, and the synergistic activity was exerted at a fourth of the concentration necessary for reserpine. Compound 1 was not found to exert a synergistic effect on ciprofloxacin against a norA deletion mutant. The 2,3-coumaroyl isomer of compound 1 has been shown previously not to cause acute toxicity in mice at 20 mg/kg/day. CONCLUSIONS Our results show that compound 1 acts through inhibition of the NorA efflux pump. Combination of compound 1 with subinhibitory concentrations of ciprofloxacin renders a wild-type more susceptible and a NorA overexpresser S. aureus susceptible.
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Affiliation(s)
- Jes Gitz Holler
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Svarstad E, Myking O, Ofstad J, Iversen BM. Effect of light exercise on renal hemodynamics in patients with hypertension and chronic renal disease. SCANDINAVIAN JOURNAL OF UROLOGY AND NEPHROLOGY 2003; 36:464-72. [PMID: 12623513 DOI: 10.1080/003655902762467648] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Increased physical activity is followed by a stimulation of the sympathetic nervous system and this effect is probably more pronounced in patients with chronic renal failure and hypertension than in healthy controls. The role of sustained exercise in hypertensive patients with chronic renal failure, with and without antihypertensive therapy, is unclear, as is hormonal regulation of the renal hemodynamics. We hypothesized that prolonged low-intensity bicycle exercise would have a greater effect in patients with chronic renal failure than in controls, and that antihypertensive treatment would ameliorate these effects. MATERIAL AND METHODS Glomerular filtration rate (GFR), effective renal plasma flow (ERPF), mean arterial blood pressure (MAP), norepinephrine (NE) and atrial natriuretic peptide (ANP) were measured in the upright position before and during low-intensity exercise for 2 h in healthy controls (n = 8) and in hypertensive patients with moderately reduced renal function who were not taking antihypertensives (n = 7) or who were receiving treatment with captopril (n = 10), enalapril (n = 6) or verapamil (n = 9). RESULTS GFR tended to decrease and ERPF decreased significantly in healthy individuals when exercise duration was prolonged from 1 to 2 h. An earlier decline in GFR and ERPF was seen in the renal failure patients compared with the controls. Filtration fraction (FF) increased during exercise in all groups except the group taking enalapril. MAP increased in the captopril group during exercise but was unchanged in the other groups. Treatment with captopril produced a more pronounced and earlier fall in exercise-induced GFR than in untreated controls, while verapamil treatment completely blunted the decline in GFR, with a concomitant increase in plasma ANP. No significant changes were seen in plasma NE levels, but urinary NE excretion increased in controls and captopril-treated patients during exercise. CONCLUSIONS The results suggest that prolonged low-intensity exercise has a substantially greater effect on renal hemodynamics in hypertensive renal failure patients than in healthy controls, with negligible changes in plasma NE levels. Verapamil treatment seems to ameliorate the renal effects of exercise on GFR in these patients, and this may in part be mediated via a stimulatory effect on ANP.
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Affiliation(s)
- E Svarstad
- Renal Research Group, Institute of Medicine, Bergen, Norway.
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8
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Lefrandt JD, Heitmann J, Sevre K, Castellano M, Hausberg M, Fallon M, Urbigkeit A, Rostrup M, Agabiti-Rosei E, Rahn KH, Murphy M, Zannad F, de Kam PJ, Smit AJ. Contrasting effects of verapamil and amlodipine on cardiovascular stress responses in hypertension. Br J Clin Pharmacol 2001; 52:687-92. [PMID: 11736880 PMCID: PMC2014561 DOI: 10.1046/j.0306-5251.2001.01507.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS To compare the effects of two long-acting calcium antagonists of different types on cardiovascular stress responses in hypertension. METHODS One-hundred and forty-five patients with mild to moderate hypertension and a mean (+/- s.e.mean) age of 51 +/- 0.9 years received for 8 weeks the phenylalkylamine verapamil sustained release (240 mg) and the dihydropyridine amlodipine (5 mg) in a double-blind cross-over design, both after 4 weeks of placebo. Blood pressure, heart rate and plasma noradrenaline were monitored during 3 min of sustained isometric handgrip and 2 min of cold pressor. RESULTS Blood pressure was equally reduced by both drugs. After 3 min handgrip, systolic blood pressure, heart rate and rate-pressure product were lower with verapamil compared with amlodipine. Verapamil attenuated the increases in systolic blood pressure (25 +/- 2 vs 30 +/- 2 mmHg, difference 4.6, 95% CI (1.0, 8.1), P < 0.01) and rate-pressure product (3.1 +/- 0.2 vs 3.6 +/- 0.3 x 10(3) mmHg x beats min(-1), difference 0.5, 95% CI (0.1, 0.9), P < 0.01) during handgrip compared with amlodipine. Similar results were observed during cold pressor. Plasma noradrenaline levels were lower with verapamil compared with amlodipine at rest and after both tests, but the increases in plasma noradrenaline were not significantly different. CONCLUSIONS Verapamil is more effective in reducing blood pressure and rate-pressure product responses to stress compared with amlodipine. Although plasma noradrenaline is lower with verapamil at rest and after stress, the increase during stress is not different.
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Affiliation(s)
- J D Lefrandt
- University Hospital of Groningen, Department of Internal Medicine, Groningen, The Netherlands.
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Murzenok PP, Huang BS, Leenen FH. Sympathoinhibition by central and peripheral infusion of nifedipine in spontaneously hypertensive rats. Hypertension 2000; 35:631-6. [PMID: 10679509 DOI: 10.1161/01.hyp.35.2.631] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study assessed whether central mechanisms may contribute to the hypotensive effect of the calcium channel blocker nifedipine. In conscious, spontaneously hypertensive rats (SHR) on a high-salt diet, hemodynamic (mean arterial pressure [MAP] and heart rate) and sympathetic (renal sympathetic nerve activity) responses to low, central, intracerebroventricular infusion rates (25 microg. kg(-1). h(-1) for 2 hours) and peripheral intravenous rates (50 microg. kg(-1). h(-1) for 3 hours and then 100 microg. kg(-1). h(-1) for 2 hours) of nifedipine were evaluated. The distribution of nifedipine in the blood and tissues was assessed at the end of the infusions. Nifedipine significantly inhibited renal sympathetic nerve activity and lowered MAP in SHR beginning 30 minutes after the start of the intracerebroventricular infusion. The decrease of MAP by intravenous infusion began at 60 minutes and was more profound with 100 microg. kg(-1). h(-1). Inhibition of sympathetic activity preceded and then paralleled the decrease in blood pressure; it occurred earlier with central (15 to 30 minutes) than with peripheral (30 to 60 minutes) infusion. Intravenous infusion resulted in concentrations of nifedipine in brain structures (brain stem, midbrain, and cortex) that were 30% to 40% of those in the heart, kidneys, and liver. From the hemodynamic and sympathetic responses and the distribution of nifedipine into the central nervous system, we conclude that the peripheral infusion of nifedipine at relatively low rates may evoke a hypotensive response in SHR, not only via peripheral mechanisms, but also through central mechanisms, which will lead to an inhibition of sympathetic outflow and, therefore, a lowering of blood pressure.
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Affiliation(s)
- P P Murzenok
- University of Ottawa Heart Institute, Ontario, Canada
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Terland O, Flatmark T. Energy-dependent accumulation of calcium antagonists in catecholamine storage vesicles. Biochem Pharmacol 2000; 59:123-9. [PMID: 10810446 DOI: 10.1016/s0006-2952(99)00307-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The calcium antagonists verapamil, nitrendipine, mibefradil, and amlodipine accumulate in chromaffin granule ghosts with apparent equilibrium partition coefficients [(mol/mg membrane lipid)/(mol/mg solvent water)] of 246 +/- 105 (N = 8), 2700 +/- 600 (N = 4), 7400 +/- 2200 (N = 4), and 8100 +/- 1100 (N = 5), respectively. In the presence of 1.2 mM MgATP, the partition coefficients were 854 +/- 206 (N = 10), 2300 +/- 600 (N = 4), 32,700 +/- 8,900 (N = 7), and 20,300 +/- 5,000 (N = 11) for verapamil, nitrendipine, mibefradil, and amlodipine, respectively. Except for nitrendipine, the apparent partition coefficients in the presence of MgATP were significantly different from the control (P < 0.001). For amlodipine and verapamil, the vacuolar H(+)-ATPase inhibitors bafilomycin A1 (30 nM) and N-ethylmaleimide (2 mM) and the protonophore (uncoupler) carbonyl cyanide m-chlorophenylhydrazone (CCCP, 10 microM) completely blocked the increase in partition coefficients in response to MgATP. The extra amlodipine, mibefradil, and verapamil that accumulated in response to MgATP were released into the medium by CCCP (10 microM) by 18% (N = 5), 30% (N = 5), and 88% (N = 5) for amlodipine, mibefradil, and verapamil, respectively. Thus, amlodipine, mibefradil, and verapamil, but not nitrendipine, accumulate in catecholamine storage vesicles in response to delta mu H+ generated by the endogenous V-type H(+)-ATPase, and are partially released by de-energetisation. Hence, these calcium antagonists can reach unexpectedly high concentrations in certain target cells, and give pharmacodynamic properties not shared by nitrendipine.
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Affiliation(s)
- O Terland
- Department of Biochemistry and Molecular Biology, University of Bergen, Norway
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Terland O, Flatmark T. Drug-induced parkinsonism: cinnarizine and flunarizine are potent uncouplers of the vacuolar H+-ATPase in catecholamine storage vesicles. Neuropharmacology 1999; 38:879-82. [PMID: 10465691 DOI: 10.1016/s0028-3908(98)00233-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cinnarizine (1-diphenylmethyl-4-(3-phenyl-2-propenyl)piperazine) and its di-fluorinated derivative flunarizine inhibit the MgATP-dependent generation of a transmembrane proton electrochemical gradient in chromaffin granule ghosts. The concentrations giving 50% inhibition (IC50) of the MgATP-dependent generation of the pH-gradient were 5.9+/-0.6 microM (n = 6) and 3.0+/-0.3 microM (n = 5) for cinnarizine and flunarizine, respectively. The IC50 values for inhibiting the generation of the membrane potential were even lower, i.e. 0.19+/-0.06 microM (n = 6) and 0.15+/-0.01 microM (n = 4) for cinnarizine and flunarizine, respectively. Cinnarizine (10 microM) also inhibited the energy-dependent vesicular uptake of [14C]-dopamine (50 microM) by 76%, i.e. from 2.1+/-0.9 to 0.5+/-0.6 nmol/mg protein/min (n = 5, P < 0.002). Cinnarizine (10 microM) increased the MgATPase activity of the granule ghosts by 47+/-26% (n = 4) compatible with an uncoupling of the vacuolar H+-ATPase activity. The IC50-values observed for the two compounds are in the same range as their reported therapeutic plasma concentrations in vivo, suggesting that cinnarizine and flunarizine may well inhibit proton pumping and catecholamine uptake in storage vesicles also in vivo. This mechanism of action may contribute to the drug-induced parkinsonism seen as a side-effect of the two drugs.
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Affiliation(s)
- O Terland
- Department of Biochemistry and Molecular Biology, University of Bergen, Norway
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Petretta M, Canonico V, Madrid A, Mickiewicz M, Spinelli L, Marciano F, Vetrano A, Signorini A, Bonaduce D. Comparison of verapamil versus felodipine on heart rate variability in hypertensive patients. J Hypertens 1999; 17:707-13. [PMID: 10403616 DOI: 10.1097/00004872-199917050-00016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVE We evaluated the effect of two calcium channel blockers, verapamil and felodipine, on heart rate variability in hypertensive patients. DESIGN Time and frequency domain measures of heart rate variability were obtained from 24 h Holter recording in 25 previously untreated hypertensive patients without left ventricular hypertrophy, before and after 3 months of verapamil slow-release treatment (240 mg once daily) or felodipine extended-release treatment (10 mg once daily). RESULTS Blood pressure values decreased with both drugs. Measures of heart rate variability, comparable at baseline in the two groups, were unchanged after felodipine. After verapamil, the average RR interval, the square root of the mean of the squared differences between all adjacent normal RR intervals (r-MSSD) and the percentage of differences between all adjacent normal RR intervals > 50 ms (pNN50), measures of vagal modulation of heart rate, increased (from 735 +/- 67 to 827 +/- 84 ms, P < 0.001; from 30 +/- 10 to 44 +/- 15 ms, P < 0.001; and from 3 +/- 2 to 7 +/- 6%, P < 0.01, respectively) and were higher than after felodipine. The coefficient of variation, a measure that compensates for heart rate effects, increased only after verapamil (from 5.8 +/- 1.3% to 6.6 +/- 1.0%; P < 0.05). High frequency power and its coefficient of component variance, both representing the vagal modulation of heart rate, increased after verapamil (from 5.33 +/- 0.29 to 5.80 +/- 0.27 In units, P < 0.001 and from 1.9 +/- 0.3 to 2.2 +/- 0.25%; P < 0.05). Finally, the low to high frequency power ratio, an indicator of sympathovagal balance, with a high value suggesting a sympathetic predominance, decreased after verapamil (from 2.16 +/- 0.41 to 1.36 +/- 0.35; P < 0.001), confirming the improvement in vagal modulation of heart rate. CONCLUSION In hypertensive patients, despite a comparable anti-hypertensive effect, verapamil, but not felodipine, has favourable effect on cardiac autonomic control.
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Affiliation(s)
- M Petretta
- Institute of Internal Medicine, Cardiology and Heart Surgery, University of Naples Federico II, Italy
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Pinar E, García-Alberola A, Llamas C, Vicente T, López-Candel J, Rojo JL, Fernández R, Valdés M. Effects of verapamil on indexes of heart rate variability after acute myocardial infarction. Am J Cardiol 1998; 81:1085-9. [PMID: 9605046 DOI: 10.1016/s0002-9149(98)00128-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In patients with previous myocardial infarction (MI), depressed heart rate variability (HRV) may reflect a reduction in vagal activity and lead to cardiac electrical instability. Interventions designed to increase HRV may be of clinical interest. Data on the effects of calcium antagonists on HRV in post-MI patients are very limited. The aim of our study was to assess the effects of verapamil on HRV and on the sympathovagal balance after MI. Fifty consecutive patients with a first MI, stable sinus rhythm, and left ventricular ejection fraction >0.40 were studied. Each patient underwent two 24-hour Holter recordings, 1 at baseline and another after 4 days of treatment with verapamil retard (180 mg 2 times daily). Time and frequency domain parameters of HRV were analyzed. All time domain measurements increased significantly after verapamil: the standard deviation of all NN intervals (SDNN) from 87.1 +/- 31.4 to 98.1 +/- 30.3 ms (p <0.05) and the log-transformed percentage of pairs of adjacent NN intervals that differ >50 ms (pNN50) from 0.57 +/- 0.42 to 0.76 +/- 0.45 (p <0.01). The standard deviation of the averages of RR interevals (SDANN) (75.9 +/- 30.1 vs 86.3 +/- 29.4 ms, p <0.05), root-mean-square of successive differences between RR intervals (rMSSD) (23.0 +/- 11.7 and 28.1 +/- 13.1 ms, p <0.01), and the triangular HRV index (28.3 +/- 9.6 vs 23.4 +/- 8.6, p <0.001) also increased. A significant inverse correlation was found between improvement in HRV indexes induced by verapamil and baseline values. Spectral analysis showed a significant increase in high-frequency power of 58.5% without changes in low and very low components. With normalized units, significant reductions in low-frequency power and low- to high-frequency ratio were observed. Diabetic patients did not show any significant changes in HRV on administration of verapamil. These findings indicate that verapamil, administered during the subacute phase of MI, improves both global and short-period indexes of HRV and induces a shift in the sympathetic-parasympathetic interaction toward vagal predominance. This effect may contribute to an explanation of the beneficial effects of verapamil that have been reported in post-MI patients.
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Affiliation(s)
- E Pinar
- Department of Cardiology, General Hospital of the University of Murcia, Spain
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14
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Yamazaki T, Komuro I, Zou Y, Kudoh S, Shiojima I, Mizuno T, Hiroi Y, Nagai R, Yazaki Y. Efficient inhibition of the development of cardiac remodeling by a long-acting calcium antagonist amlodipine. Hypertension 1998; 31:32-8. [PMID: 9449387 DOI: 10.1161/01.hyp.31.1.32] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The purpose of the present study was to examine the effects of a long-acting calcium antagonist, amlodipine, on the development of cardiac remodeling. Dihydropyridine calcium antagonists have been used widely for many years in the treatment of hypertension and angina pectoris. It has been reported, however, that a prototype of dihydropyridines, nifedipine, does not reduce mortality of patients with ischemic heart disease, possibly because of reflex stimulation of the sympathetic nervous system. A calcium antagonist, amlodipine, has been reported to have potential benefits by virtue of a gradual onset of action and a long duration of effects. Amlodipine (8 mg/kg per day, once a day) or nifedipine (24 mg/kg per day, three times a day) was administered to spontaneously hypertensive 12-week-old rats for 12 weeks. Left ventricular wall thickness was measured by echocardiography, and relative amounts of myosin heavy chain isoforms were assessed by pyrophosphate gels. Expressions of "fetal type" genes and type 1 collagen gene were examined by Northern blot analysis. Amlodipine and nifedipine both markedly reduced systolic blood pressure. However, the decrease in systolic blood pressure caused by nifedipine continued for no more than 8 hours, whereas the blood pressure-lowering effect of amlodipine continued for more than 16 hours post dose. Amlodipine markedly reduced left ventricular wall thickness, whereas nifedipine only weakly attenuated an increase in the wall thickness. Amlodipine, but not nifedipine, prevented an increase in the relative amount of V3 myosin heavy chain isoform and suppressed an increase in mRNA levels of beta-myosin heavy chain, skeletal alpha-actin, and type 1 collagen. Unlike nifedipine, amlodipine effectively prevented cardiac remodeling secondary to high blood pressure at biochemical levels and morphological levels. These results suggest that a long-acting calcium antagonist is more effective than a short-acting one in preventing organ injury in hypertensive subjects.
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Affiliation(s)
- T Yamazaki
- Department of Medicine III, University of Tokyo School of Medicine, the Health Service Center, Japan
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15
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Prenylamine derivatives as blockers of the vesicular transporter for dopamine. A quantitative structure-activity study. Eur J Med Chem 1997. [DOI: 10.1016/s0223-5234(97)84361-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Mahata M, Mahata SK, Parmer RJ, O'Connor DT. Vesicular monoamine transport inhibitors. Novel action at calcium channels to prevent catecholamine secretion. Hypertension 1996; 28:414-20. [PMID: 8794826 DOI: 10.1161/01.hyp.28.3.414] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Vesicular monoamine transport (VMAT) inhibitors, such as reserpine and tetrabenazine, impair vesicular catecholamine storage in chromaffin cells and sympathetic neurons, thereby lowering blood pressure. Here we describe a novel action of VMAT inhibitors-blockade of L-type voltage-gated calcium channels-that may also influence catecholamine release from both PC12 rat pheochromocytoma cells and bovine adrenal chromaffin cells. When given alone, VMAT inhibitors acutely release catecholamines from chromaffin cells in a dose-dependent fashion. However, VMAT inhibitors block catecholamine secretion stimulated by either nicotinic cholinergic agonists or cell membrane depolarization, each of which rely on the opening of L-type channels; the inhibition was more potent after long-term exposure to VMAT inhibitors (IC50 < 100 nmol/L). Reserpine blocked nicotinic-stimulated catecholamine release from neurite-bearing PC12 cells. Reserpine also antagonized catecholamine release triggered by combined membrane depolarization and the dihydropyridine L-type channel agonist Bay K8644, and reserpine blocked cellular uptake of extracellular 45Ca2+ in response to nicotine. Taken together, these results indicate that VMAT inhibitors are also antagonists at L-type voltage-gated calcium channels. Classic L-type channel antagonists (verapamil or nifedipine) also exhibited the reciprocal actions; acutely, they released norepinephrine from chromaffin cells, and chronically, they depleted cellular catecholamine stores, albeit with inferior molar potency to reserpine (IC50 < 1 nmol/L). We conclude that VMAT inhibitors and L-type calcium channel antagonists exert reciprocal inhibitory actions on each other's more classic pharmacological targets. Furthermore, these novel actions are seen at concentrations of these compounds frequently taken to be specific in vitro and likely to occur during antihypertensive treatment in vivo.
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Affiliation(s)
- M Mahata
- Department of Medicine, University of California, San Diego 92161, USA
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17
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Kailasam MT, Parmer RJ, Cervenka JH, Wu RA, Ziegler MG, Kennedy BP, Adegbile IA, O'Connor DT. Divergent effects of dihydropyridine and phenylalkylamine calcium channel antagonist classes on autonomic function in human hypertension. Hypertension 1995; 26:143-9. [PMID: 7607717 DOI: 10.1161/01.hyp.26.1.143] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Calcium channel antagonists differ by class in reported frequency of side effects that suggest reflex sympathoadrenal activation. Do such differences result from differential effects on autonomic and baroreflex function? The present study compared acute and chronic effects of two classes of calcium channel antagonists, the dihydropyridine type (felodipine) and the phenylalkylamine type (verapamil), on efferent sympathetic outflow and baroreflex slope in 15 essential hypertensive subjects. Blood pressure, heart rate, hemodynamics, and biochemistries were determined at baseline and after acute (first dose) and chronic (4 weeks) administration of the drugs versus placebo. Acutely, felodipine caused a greater decrease in blood pressure associated with a larger decline in systemic vascular resistance than the corresponding effects produced by verapamil. Chronically, there were similar, significant declines in blood pressure (P = .001) and systemic vascular resistance (P = .001) after each drug. Acutely, increased sympathetic activity after felodipine was suggested by reflex tachycardia (from 69 +/- 3 to 74 +/- 2 beats per minute, P = .014) and elevation of plasma norepinephrine (from 264 +/- 25 to 323 +/- 25 pg/mL, P = .037), whereas after verapamil the corresponding changes were closely similar to those after placebo.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M T Kailasam
- Department of Medicine, University of California, San Diego 92161, USA
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Vaccari A, Saba P, Gessa G. Potent, extra-channel influence of several calcium-channel modulators on striatal binding of [3H]tyramine. Neurochem Res 1993; 18:1125-30. [PMID: 8255363 DOI: 10.1007/bf00978362] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A number of Ca(2+)-, K(+)-, and Na(+)-channel modulators has been tested with respect to their effects on [3H]tyramine (TY) binding, as a putative marker for the vesicular dopamine (DA) transporter in striatal membrane preparations containing vesicle ghosts. Among organic Ca(2+)-channel modulators, the diphenylalkylamines tested consistently inhibited TY binding: the order of potency was prenylamine > lidoflazine > flunarizine > cinnarizine, with Ki values of 0.1, 0.2, 0.5 and 1.2 microM, respectively. Low (up to 100 nM) concentrations of prenylamine did competitively inhibit TY binding, and higher concentrations provoked a mixed-type inhibition. Furthermore, LIGAND-analysis of competition curves revealed a high- and a low-affinity binding site for prenylamine and flunarizine. The TY binding process was also sensitive to selected K(+)- and Na(+)-channel modulators. Since several Ca(2+)-antagonists are known to affect H(+)-ATPase and the bioenergetics of catecholamine storage vesicles in chromaffin granules, thus affecting monoamine storage, the energy requirements for the formation of the TY/carrier complex were here assessed, assuming similarity between chromaffin granules and synaptic vesicles. TY binding, though not reflecting endovesicle-sequestered TY, was indeed strongly sensitive (with Ki coefficients in the fM or low nM range) to the dissipation of the vesicular transmembrane proton concentration (delta pH), electrical (delta psi), and proton electrochemical (delta microH+) gradients, provoked by a number of specifically targeted agents. It is concluded that Ca(2+)-channel agents of the diphenylalkylamine group may directly affect striatal TY binding due to an extrachannel-regulated competition with TY for the vesicular carrier of DA, as well indirectly, by disruption of the transmembrane energization of the reserpine-sensitive carrier.
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Affiliation(s)
- A Vaccari
- Department of Neuroscience B. Brodie, Cagliari, Italy
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Mundal HH, Gjesdal K, Landmark K. The effect of N-3 fatty acids and nifedipine on platelet function in hypertensive males. Thromb Res 1993; 72:257-62. [PMID: 8303664 DOI: 10.1016/0049-3848(93)90192-q] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- H H Mundal
- Department of Cardiology, Ullevål University Hospital, Oslo, Norway
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20
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Abstract
The [3H]Tyramine (TY) binding site is proposed as a high affinity marker of the membrane carrier for dopamine (DA) in synaptic vesicles from DA-rich brain regions. Under precise assay conditions, there is neither a consistent association of TY with the neuronal, cocaine-sensitive DA transporter, nor with mitochondrial or microsomal targets. TY-labeled sites have a high affinity for selected toxins such as the Parkinsonian agent MPP+ (1-methyl-4-phenylpyridinium ion), or drugs such as diphenylalkylamine Ca(2+)-channel antagonists. The MPP+/TY site interaction, which in the striatum leads to depletion of vesicular DA, occurs in dopaminergic as well as in noradrenergic regions, though with different kinetic profiles. TY-labeled carriers for DA and noradrenaline (NA) in respective vesicles seem to be different entities, which might result in a region-specific rate of toxin sequestration and/or release from heterogeneous vesicles. Whereas MPP+ is a potent competitive-type inhibitor of [3H]TY binding, prenylamine-like Ca(2+)-channel antagonists can compete with TY for the vesicle site, in a tetrabenazine- or reserpine-like manner, and also inhibit TY binding thanks to the extra-channel directed impairment of membrane bioenergetics they are proposed to provoke. This follows from the generally-accepted assumption that similar mechanisms are operational for secretory organelles in adrenals and CNS, and from the marked sensitivity of TY binding to miscellaneous energy-disrupting agents.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A Vaccari
- Department of Neuroscience, B. Brodie, Cagliari, Italy
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21
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Terland O. Treatment of chronic heart failure. Lancet 1992; 340:670-1. [PMID: 1355227 DOI: 10.1016/0140-6736(92)92202-q] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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