β-Subunit–Dependent Modulation of hSlo BK Current by Arachidonic Acid

2007 ◽  
Vol 97 (1) ◽  
pp. 62-69 ◽  
Author(s):  
X. Sun ◽  
D. Zhou ◽  
P. Zhang ◽  
E. G. Moczydlowski ◽  
G. G. Haddad
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Conformational Changes ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Nordihydroguaiaretic Acid ◽  
Bk Channels ◽  
Bk Channel ◽  
Β Subunit ◽  
Α Subunit

In this study, we examined the effect of arachidonic acid (AA) on the BK α-subunit with or without β-subunits expressed in Xenopus oocytes. In excised patches, AA potentiated the hSlo-α current and slowed inactivation only when β2/3 subunit was co-expressed. The β2-subunit–dependent modulation by AA persisted in the presence of either superoxide dismutase or inhibitors of AA metabolism such as nordihydroguaiaretic acid and eicosatetraynoic acid, suggesting that AA acts directly rather than through its metabolites. Other cis unsaturated fatty acids (docosahexaenoic and oleic acid) also enhanced hSlo-α + β2 currents and slowed inactivation, whereas saturated fatty acids (palmitic, stearic, and caprylic acid) were without effect. Pretreatment with trypsin to remove the cytosolic inactivation domain largely occluded AA action. Intracellularly applied free synthetic β2-ball peptide induced inactivation of the hSlo-α current, and AA failed to enhance this current and slow the inactivation. These results suggest that AA removes inactivation by interacting, possibly through conformational changes, with β2 to prevent the inactivation ball from reaching its receptor. Our data reveal a novel mechanism of β-subunit–dependent modulation of BK channels by AA. In freshly dissociated mouse neocortical neurons, AA eliminated a transient component of whole cell K+ currents. BK channel inactivation may be a specific mechanism by which AA and other unsaturated fatty acids influence neuronal death/survival in neuropathological conditions.

scholarly journals Detrusor overactivity is associated with downregulation of large-conductance calcium- and voltage-activated potassium channel protein

2010 ◽  
Vol 298 (6) ◽  
pp. F1416-F1423 ◽  
Author(s):  
Shaohua Chang ◽  
Cristiano Mendes Gomes ◽  
Joseph A. Hypolite ◽  
James Marx ◽  
Jaber Alanzi ◽  
...  
Keyword(s):  
Detrusor Overactivity ◽  
Bladder Outlet Obstruction ◽  
Rabbit Model ◽  
Outlet Obstruction ◽  
Bk Channels ◽  
Bk Channel ◽  
Β Subunit ◽  
Α Subunit ◽  
Translational Study ◽  
Channel Expression

Large-conductance voltage- and calcium-activated potassium (BK) channels have been shown to play a role in detrusor overactivity (DO). The goal of this study was to determine whether bladder outlet obstruction-induced DO is associated with downregulation of BK channels and whether BK channels affect myosin light chain 20 (MLC20) phosphorylation in detrusor smooth muscle (DSM). Partial bladder outlet obstruction (PBOO) was surgically induced in male New Zealand White rabbits. The rabbit PBOO model shows decreased voided volumes and increased voiding frequency. DSM from PBOO rabbits also show enhanced spontaneous contractions compared with control. Both BK channel α- and β-subunits were significantly decreased in DSM from PBOO rabbits. Immunostaining shows BKβ mainly expressed in DSM, and its expression is much less in PBOO DSM compared with control DSM. Furthermore, a translational study was performed to see whether the finding discovered in the animal model can be translated to human patients. The urodynamic study demonstrates several overactive DSM contractions during the urine-filling stage in benign prostatic hyperplasia (BPH) patients with DO, while DSM is very quiet in BPH patients without DO. DSM biopsies revealed significantly less BK channel expression at both mRNA and protein levels. The degree of downregulation of the BK β-subunit was greater than that of the BK α-subunit, and the downregulation of BK was only associated with DO, not BPH. Finally, the small interference (si) RNA-mediated downregulation of the BK β-subunit was employed to study the effect of BK depletion on MLC20 phosphorylation. siRNA-mediated BK channel reduction was associated with an increased MLC20 phosphorylation level in cultured DSM cells. In summary, PBOO-induced DO is associated with downregulation of BK channel expression in the rabbit model, and this finding can be translated to human BPH patients with DO. Furthermore, downregulation of the BK channel may contribute to DO by increasing the basal level of MLC20 phosphorylation.

scholarly journals The β Subunit Increases the Ca2+ Sensitivity of Large Conductance Ca2+-activated Potassium Channels by Retaining the Gating in the Bursting States

1999 ◽  
Vol 113 (3) ◽  
pp. 425-440 ◽  
Author(s):  
Crina M. Nimigean ◽  
Karl L. Magleby
Keyword(s):  
Single Channel ◽  
Bk Channels ◽  
Bk Channel ◽  
Β Subunit ◽  
Open Probability ◽  
Α Subunit ◽  
Closed Intervals ◽  
Single Channel Analysis ◽  
Channel Analysis ◽  
The Mean

Coexpression of the β subunit (KV,Caβ) with the α subunit of mammalian large conductance Ca2+- activated K+ (BK) channels greatly increases the apparent Ca2+ sensitivity of the channel. Using single-channel analysis to investigate the mechanism for this increase, we found that the β subunit increased open probability (Po) by increasing burst duration 20–100-fold, while having little effect on the durations of the gaps (closed intervals) between bursts or on the numbers of detected open and closed states entered during gating. The effect of the β subunit was not equivalent to raising intracellular Ca2+ in the absence of the beta subunit, suggesting that the β subunit does not act by increasing all the Ca2+ binding rates proportionally. The β subunit also inhibited transitions to subconductance levels. It is the retention of the BK channel in the bursting states by the β subunit that increases the apparent Ca2+ sensitivity of the channel. In the presence of the β subunit, each burst of openings is greatly amplified in duration through increases in both the numbers of openings per burst and in the mean open times. Native BK channels from cultured rat skeletal muscle were found to have bursting kinetics similar to channels expressed from alpha subunits alone.

Inhibition by polyunsaturated fatty acids of cell volume regulation and osmolyte fluxes in astrocytes

1995 ◽  
Vol 269 (1) ◽  
pp. C96-C102 ◽  
Author(s):  
R. Sanchez-Olea ◽  
M. Morales-Mulia ◽  
J. Moran ◽  
H. Pasantes-Morales
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Polyunsaturated Fatty Acids ◽  
Cell Volume ◽  
Metabolic Pathways ◽  
Saturated Fatty Acids ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Nordihydroguaiaretic Acid ◽  
Arachidonic Acid Metabolite

The polyunsaturated fatty acids, arachidonic, linoleic, and linolenic acids, were potent blockers of regulatory volume decrease (RVD) and of the swelling-activated efflux of [3H]taurine, D-[3H]aspartate, [3H]inositol, and 125I (used as marker of Cl) from rat cerebellar astrocytes in culture. The monounsaturated oleic and ricinoleic acids and saturated fatty acids were ineffective. The amino acid and 125I fluxes were similarly inhibited by fatty acids, whereas inositol release was less sensitive. Polyunsaturated fatty acids appear to directly affect RVD in trypsinized astrocytes as the inhibition was immediate and fully reversible. Blockers of the arachidonic acid metabolic pathways, indomethacin (cyclooxygenase), esculetin (lipoxygenases), and metyrapone (P-450 monooxygenases), did not prevent the effect of arachidonic acid, suggesting that further metabolism is not required for displaying the effects of arachidonic acid on RVD and osmolyte fluxes. Some blockers of arachidonic acid metabolic pathways, such as nordihydroguaiaretic acid (lipoxygenases) and naphthoflavone (P-450 monooxygenases), also exhibited marked inhibitory effects on RVD and on osmolyte fluxes. The predominant arachidonic acid metabolite in astrocytes, 12-hydroxyeicosatetraenoic acid, did not affect RVD or osmolyte fluxes. These results suggest that arachidonic acid and other polyunsaturated fatty acids directly inhibit the permeability pathways correcting cell volume after swelling in cultured astrocytes.

scholarly journals nalysis of Fatty Acid Composition in the Flesh of Boal (Wallagu Attu)

2019 ◽  
Vol 16 (2) ◽  
pp. 477-481
Author(s):  
Pinak Dutta ◽  
Mita Dutta
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
West Bengal ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Fish Muscle ◽  
Nervonic Acid

The fatty acid composition of the muscle tissue of Wallagu attu found in Gangetic West Bengal, India was investigated to get an insight of its nutritional capacity. The fish muscle proved to be a rich source of both mono and poly unsaturated fatty acids. Of the saturated fatty acids Palmitic and Heneicosanoic acid is detected in considerable amount. Of the MUFA’s present Palmetoleic acid, Elaidic acid, Oleic acid and nervonic acid is found in good amount. Nutritionally important ω-6 PUFA’s like Linoleic acid and Arachidonic acid are found in the fish. EPA and DHA the two star ω-3 PUFA’s whose health benefits are beyond doubt are also detected in the fish. Wallagu attu is generally not farmed as it devours other fishes but considering its nutritional capacity and high market demands, its farming may prove beneficial for consumers and producers.

scholarly journals Evidence for a single non-arachidonic acid-specific fatty acyl-CoA synthetase in heart which is regulated by Mg2+

1996 ◽  
Vol 313 (3) ◽  
pp. 849-853 ◽  
Author(s):  
Christine SAUNDERS ◽  
Jeffrey M. VOIGT ◽  
Margaret T. WEIS
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Oleic Acid ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Rabbit Heart ◽  
Fatty Acyl ◽  
Synthetase Activity ◽  
Low Concentrations ◽  
Rate Limiting

Previous reports indicated that arachidonic acid is incorporated into the isolated perfused rabbit heart in preference to other fatty acids, and that incorporation of arachidonic acid, but not other fatty acids, is inhibited during Mg2+ depletion. In this study, we have not been able to demonstrate an arachidonic acid-specific fatty acyl-CoA synthetase in rat or rabbit heart by hydroxyapatite chromatography. Kinetic evidence was consistent with a single enzyme, as the slopes of pseudo-Hill plots were not significantly different from -1. The single fatty acyl-CoA synthetase present appears to prefer C18:0 unsaturated fatty acids to arachidonate, and had about the same affinity for C10:0–C14:0 saturated fatty acids as for arachidonate. At 35 μM arachidonate, enzyme velocity increased as the total Mg2+ was increased from 3 to 80 mM. Calculated [MgATP] indicated that the MgATP complex was not rate-limiting. At low concentrations, Mn2+ and Ni2+ supported activity, but Cu2+ and Zn2+ did not. Low Ca2+ concentrations activated only oleic acid conversion. Kinetic analysis indicated that the Vmax of the enzyme was increased with increasing concentrations of ionized Mg2+ for both oleic acid and arachidonic acid. The data are consistent with the hypothesis that Mg2+ has a direct effect on fatty acyl-CoA synthetase activity, and suggest that preference for oleic acid and arachidonic acid can be influenced by the ionic milieu.

scholarly journals Influence of irradiance on the growth and biochemical composition of Nitzschia aff. pellucida

2021 ◽  
Author(s):  
Isaac Lisondro ◽  
Cintia Gómez Serrano ◽  
Claudia Sepúlveda ◽  
Ariadna Indira Batista Ceballos ◽  
Francisco Gabriel Acién Fernández
Keyword(s):  
Fatty Acids ◽  
Growth Rate ◽  
Arachidonic Acid ◽  
Biochemical Composition ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Continuous Mode ◽  
Biological Interest ◽  
Cultivation Mode ◽  
Average Irradiance

AbstractIn this paper the influence of irradiance and the operation modes on biomass production and biochemical composition, especially the fatty acid profile, on the diatom Nitzschia aff. pellucida was studied. Experiments were carried out under laboratory conditions, but simulating those outdoors, at irradiances ranging from 100 to 1000 µmol photons m−2 s−1, both in batch and semi-continuous mode. The data show that the growth rate increased with irradiance, following a hyperbolic relationship with the average irradiance (Eav). However, at irradiances higher than 450 µmol photons m−2 s−1, photo-inhibition was observed, with Fv/Fm values notably decreasing at irradiances above 1000 µmol photons m−2 s−1. To take account of this phenomenon, a growth model is proposed that considers the saturation constant modification (Ek) as a function of available irradiance. The data indicate that N. aff. pellucida is better adapted to low irradiances, below 300 µmol photons m−2 s−1. Regarding the biochemical composition, the highest content of lipids (~ 20%) and carbohydrates (~ 40%) was achieved at high irradiances (≥ 450 µmol photons m−2 s−1), while the highest protein content (> 8%) was found at low irradiances (≤ 200 µmol photons m−2 s−1). Elevated amounts of saturated fatty acids (SFA) (> 60%) were measured at high irradiances, while the highest content of unsaturated fatty acids (USFA) (> 35%) was found at low irradiances. Eicosapentaenoic acid (C20:5 n-3) (EPA) and arachidonic acid (C20:4 n-6) (ARA) were only detected at 200 µmol m−2 s−1 but not at higher irradiances. The results confirm the effects of irradiance and the cultivation mode on the growth and biochemical composition of N. aff. pellucida. The model is an important tool when using this valuable strain to produce compounds of biological interest.

DEVELOPMENT OF AN EXPERIMENTAL MODEL OF AVITAMINOSIS F

2020 ◽  
Vol 20 (2) ◽  
pp. 38-40
Author(s):  
A. Levitsky ◽  
A. Lapinska ◽  
I. Selivanskaya
Keyword(s):  
Fatty Acids ◽  
Experimental Model ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Coconut Oil ◽  
The Body ◽  
Regulatory Function ◽  
Omega 3 ◽  
White Rats ◽  
Arachidonic Acids

The article analyzes the role of essential polyunsaturated fatty acids (PUFA), especially omega-3 series in humans and animals. The biosynthesis of essential PUFA in humans and animals is very limited, so they must be consumed with food (feed). Тhe ratio of omega-3 and omega-6 PUFA is very important. Biomembranes of animal cells contain about 30% PUFA with a ratio of ω-6/ ω-3 1-2. As this ratio increases, the physicochemical properties of biomembranes and the functional activity of their receptors change. The regulatory function of essential PUFA is that in the body under the action of oxygenase enzymes (cyclooxygenase, lipoxygenase) are formed extremely active hormone-like substances (eicosanoids and docosanoids), which affect a number of physiological processes: inflammation, immunity, metabolism. Moreover, ω-6 PUFA form eicosanoids, which have pro-inflammatory, immunosuppressive properties, and ω-3 PUFAs form eicosanoids and docosanoids, which have anti-inflammatory and immunostimulatory properties. Deficiency of essential PUFA, and especially ω-3 PUFA, leads to impaired development of the body and its state of health, which are manifestations of avitaminosis F. Prevention and treatment of avitaminosis F is carried out with drugs that contain PUFA. To create new, more effective vitamin F preparations, it is necessary to reproduce the model of vitamin F deficiency. An experimental model of vitamin F deficiency in white rats kept on a fat –free diet with the addition of coconut oil, which is almost completely free of unsaturated fatty acids, and saturated fatty acids make up almost 99 % of all fatty acids was developed. The total content of ω-6 PUFA (sum of linoleic and arachidonic acids), the content of ω-3 PUFA (α-linolenic, eicosapentaenoic and docosahexaenoic acids) in neutral lipids (triglycerides and cholesterol esters) defined. Тhe content of ω-6 PUFA under the influence of coconut oil decreased by 3.3 times, and the content of ω-3 PUFA - by 7.5 times. Тhe influence of coconut oil, the content of ω-6 PUFA decreased by 2.1 times, and the content of ω-3 PUFA - by 2.8 times. The most strongly reduces the content of ω-3 PUFA, namely eicosapentaenoic, coconut oil, starting from 5 %. Consumption of FFD with a content of 15 % coconut oil reduces the content of eicosapentaenoic acid to zero, ie we have an absolute deficiency of one of the most important essential PUFAs, which determined the presence of vitamin F deficiency.

EFFECT OF GINGER, LEMURU FISH OIL SAPONIFICATION AND OLIVE OIL ON COMPOSITION FATTY ACID OF BEEF

2014 ◽  
Vol 4 (1) ◽  
pp. 31-39
Author(s):  
Siwitri Kadarsih
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fish Oil ◽  
Olive Oil ◽  
Rice Bran ◽  
Dry Matter ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Omega 3 ◽  
Omega 6

The objective was to get beef that contain unsaturated fatty acids (especially omega 3 and 6), so as to improve intelligence, physical health for those who consume. The study design using CRD with 3 treatments, each treatment used 4 Bali cattle aged approximately 1.5 years. Observations were made 8 weeks. Pasta mixed with ginger provided konsentrat. P1 (control); P2 (6% saponification lemuru fish oil, olive oil 1%; rice bran: 37.30%; corn: 62.70%; KLK: 7%, ginger paste: 100 g); P3 (lemuru fish oil saponification 8%, 2% olive oil; rice bran; 37.30; corn: 62.70%; KLK: 7%, ginger paste: 200 g). Konsentrat given in the morning as much as 1% of the weight of the cattle based on dry matter, while the grass given a minimum of 10% of the weight of livestock observation variables include: fatty acid composition of meat. Data the analyzies qualitative. The results of the study showed that the composition of saturated fatty acids in meat decreased and an increase in unsaturated fatty acids, namely linoleic acid (omega 6) and linolenic acid (omega 3), and deikosapenta deikosaheksa acid.Keywords : 

Differential Effects of Dietary Fatty Acids on Body Composition and Adiposity

2020 ◽  
Vol 16 (2) ◽  
pp. 142-154 ◽  
Author(s):  
Hadi Emamat ◽  
Zahra Yari ◽  
Hossein Farhadnejad ◽  
Parvin Mirmiran
Keyword(s):  
Fatty Acids ◽  
Body Composition ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Total Body Weight ◽  
Fat Distribution ◽  
Monounsaturated Fatty Acids ◽  
Dietary Fatty Acids ◽  
Dietary Fats ◽  
Total Body

Recent evidence has highlighted that fat accumulation, particularly abdominal fat distribution, is strongly associated with metabolic disturbance. It is also well-recognized that the metabolic responses to variations in macronutrients intake can affect body composition. Previous studies suggest that the quality of dietary fats can be considered as the main determinant of body-fat deposition, fat distribution, and body composition without altering the total body weight; however, the effects of dietary fats on body composition have controversial results. There is substantial evidence to suggest that saturated fatty acids are more obesogen than unsaturated fatty acids, and with the exception of some isomers like conjugate linoleic acid, most dietary trans fatty acids are adiposity enhancers, but there is no consensus on it yet. On the other hand, there is little evidence to indicate that higher intake of the n-3 and the n-6 polyunsaturated fatty acids can be beneficial in attenuating adiposity, and the effect of monounsaturated fatty acids on body composition is contradictory. Accordingly, the content of this review summarizes the current body of knowledge on the potential effects of the different types of dietary fatty acids on body composition and adiposity. It also refers to the putative mechanisms underlying this association and reflects on the controversy of this topic.

scholarly journals Explore the gene network regulating the composition of fatty acids in cottonseed

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lihong Ma ◽  
Xinqi Cheng ◽  
Chuan Wang ◽  
Xinyu Zhang ◽  
Fei Xue ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Linolenic Acid ◽  
Gene Network ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Accumulation Pattern ◽  
Time Points ◽  
Expression Characteristics

Abstract Background Cottonseed is one of the major sources of vegetable oil. Analysis of the dynamic changes of fatty acid components and the genes regulating the composition of fatty acids of cottonseed oil is of great significance for understanding the biological processes underlying biosynthesis of fatty acids and for genetic improving the oil nutritional qualities. Results In this study, we investigated the dynamic relationship of 13 fatty acid components at 12 developmental time points of cottonseed (Gossypium hirsutum L.) and generated cottonseed transcriptome of the 12 time points. At 5–15 day post anthesis (DPA), the contents of polyunsaturated linolenic acid (C18:3n-3) and saturated stearic acid (C18:0) were higher, while linoleic acid (C18:2n-6) was mainly synthesized after 15 DPA. Using 5 DPA as a reference, 15,647 non-redundant differentially expressed genes were identified in 10–60 DPA cottonseed. Co-expression gene network analysis identified six modules containing 3275 genes significantly associated with middle-late seed developmental stages and enriched with genes related to the linoleic acid metabolic pathway and α-linolenic acid metabolism. Genes (Gh_D03G0588 and Gh_A02G1788) encoding stearoyl-ACP desaturase were identified as hub genes and significantly up-regulated at 25 DPA. They seemed to play a decisive role in determining the ratio of saturated fatty acids to unsaturated fatty acids. FAD2 genes (Gh_A13G1850 and Gh_D13G2238) were highly expressed at 25–50 DPA, eventually leading to the high content of C18:2n-6 in cottonseed. The content of C18:3n-3 was significantly decreased from 5 DPA (7.44%) to 25 DPA (0.11%) and correlated with the expression characteristics of Gh_A09G0848 and Gh_D09G0870. Conclusions These results contribute to our understanding on the relationship between the accumulation pattern of fatty acid components and the expression characteristics of key genes involved in fatty acid biosynthesis during the entire period of cottonseed development.

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