Regulation of human placental chloride channel by arachidonic acid and other cis unsaturated fatty acids

1999 ◽  
Vol 180 (2) ◽  
pp. 469-475 ◽  
Author(s):  
Gloria Riquelme ◽  
Mauro Parra
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Chloride Channel ◽  
Unsaturated Fatty Acids

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 Effect of 5-trans isomer of arachidonic acid on model liposomal membranes studied by a combined simulation and experimental approach

2018 ◽  
Author(s):  
Ioanna Tremi ◽  
Dimitrios Anagnostopoulos ◽  
Ellas Spyratou ◽  
Paraskevi Gkeka ◽  
Alexandros G. Georgakilas ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Free Radicals ◽  
Lipid Bilayers ◽  
Unsaturated Fatty Acids ◽  
Md Simulations ◽  
Γ Irradiation ◽  
Physiological Concentration ◽  
Increased Risk ◽  
Average Size

AbstractUnsaturated fatty acids are found in humans predominantly in the cis configuration. Fatty acids in the trans configuration are primarily the result of human processing (trans fats), but can also be formed endogenously by radical stress. The cis-trans isomerization of fatty acids by free radicals could be connected to several pathologies. Trans fats have been linked to an increased risk of coronary artery disease; however, the reasons for the resulting pathogenesis remain unclear. Here, we investigate the effect of a mono trans isomer of arachidonic acid (C20:4-5trans,8cis,11cis,14cis) produced by free radicals in physiological concentration on a model erythrocyte membrane using a combined experimental and theoretical approach. Molecular Dynamics (MD) simulations of two model lipid bilayers containing arachidonic acid and its 5-trans isomer in 3% mol. were carried out for this purpose. The 5-trans isomer formation in the phospholipids was catalyzed by HOCH2CH2S• radicals, generated from the corresponding thiol by γ-irradiation, in multilamellar vesicles (MLVs) of SAPC. Large unilamellar vesicles were made by the extrusion method (LUVET) as a biomimetic model for cis-trans isomerization. Atomic Force Microscopy and Dynamic Light Scattering were used to measure the average size, morphology, and the z-potential of the liposomes. Both results from MD simulations and experiments are in agreement and indicate that the two model membranes display different physicochemical properties in that the bilayers containing the trans fatty acids were more ordered and more rigid than those containing solely the cis arachidonic acid. Correspondingly, the average size of the liposomes containing trans isomers was smaller than the ones without.

scholarly journals Lymphocytes possess an electrogenic H+-transporting pathway in their plasma membrane

1994 ◽  
Vol 301 (2) ◽  
pp. 329-334 ◽  
Author(s):  
K Káldi ◽  
K Szászi ◽  
K Suszták ◽  
A Kapus ◽  
E Ligeti
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Nadph Oxidase ◽  
Unsaturated Fatty Acids ◽  
Free Movement ◽  
Intracellular Acidification ◽  
Transport Pathway ◽  
Peripheral Lymphocytes ◽  
Bivalent Cations

The existence of an electrogenic H(+)-transporting pathway similar to that described in the plasma membrane of granulocytes and macrophages is reported in pig peripheral lymphocytes. The function of the H(+)-transport pathway can only be detected when free movement of charge-compensating cations is allowed. H+ transport is stimulated by arachidonic acid and various unsaturated fatty acids, and inhibited by bivalent cations, with the following sequence of efficiency: Zn2+ > Cd2+ = Co2+ = Ni2+ > Mn2+ > Ba2+ = Ca2+ = Mg2+. The transport pathway is activated by intracellular acidification and by NN'-dicyclohexylcarbodiimide, but it is not influenced by phorbol 12-myristate 13-acetate. As pig peripheral lymphocytes are not able to produce O2-., it is suggested that the operation of the electrogenic H+ conductance does not require the assembly of a functional NADPH oxidase.

scholarly journals Changes of fatty acid aerosol hygroscopicity induced by ozonolysis under humid conditions

2008 ◽  
Vol 8 (16) ◽  
pp. 4683-4690 ◽  
Author(s):  
O. Vesna ◽  
S. Sjogren ◽  
E. Weingartner ◽  
V. Samburova ◽  
M. Kalberer ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Oleic Acid ◽  
Growth Factor ◽  
Atmospheric Aerosols ◽  
Unsaturated Fatty Acids ◽  
Flow Reactor ◽  
Atmospheric Conditions ◽  
Criegee Intermediates ◽  
Induced Changes

Abstract. Unsaturated fatty acids are important constituents of the organic fraction of atmospheric aerosols originating from biogenic or combustion sources. Oxidative processing of these may change their interaction with water and thus affect their effect on climate. The ozonolysis of oleic and arachidonic acid aerosol particles was studied under humid conditions in a flow reactor at ozone exposures close to atmospheric levels, at concentrations between 0.5 and 2 ppm. While oleic acid is a widely used proxy for such studies, arachidonic acid represents polyunsaturated fatty acids, which may decompose into hygroscopic products. The hygroscopic (diameter) growth factor at 93% relative humidity (RH) of the oxidized arachidonic particles increased up to 1.09 with increasing RH during the ozonolysis. In contrast, the growth factor of oleic acid was very low (1.03 at 93% RH) and was almost invariant to the ozonolysis conditions, so that oleic acid is not a good model to observe oxidation induced changes of hygroscopicity under atmospheric conditions. We show for arachidonic acid particles that the hygroscopic changes induced by humidity during ozonolysis are accompanied by about a doubling of the ratio of carboxylic acid protons to aliphatic protons. We suggest that, under humid conditions, the reaction of water with the Criegee intermediates might open a pathway for the formation of smaller acids that lead to more significant changes in hygroscopicity. Thus the effect of water to provide a competing pathway during ozonolysis observed in this study should be motivation to include water, which is ubiquitously present in and around atmospheric particles, in future studies related to aerosol particle aging.

scholarly journals Arachidonic acid inhibits glycine transport in cultured glial cells

1990 ◽  
Vol 271 (1) ◽  
pp. 237-242 ◽  
Author(s):  
F Zafra ◽  
R Alcantara ◽  
J Gomeza ◽  
C Aragon ◽  
C Gimenez
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Unsaturated Fatty Acids ◽  
Membrane Vesicle ◽  
Selective Inhibition ◽  
Inhibitory Effect ◽  
C6 Glioma Cells ◽  
Plasma Membrane Vesicle ◽  
Glycine Uptake ◽  
Glycine Transport

The effects of arachidonic acid on glycine uptake, exchange and efflux in C6 glioma cells were investigated. Arachidonic acid produced a dose-dependent inhibition of high-affinity glycine uptake. This effect was not due to a simple detergent-like action on membranes, as the inhibition of glycine transport was most pronounced with cis-unsaturated long-chain fatty acids, whereas saturated and trans-unsaturated fatty acids had relatively little or no effect. Endogenous unsaturated non-esterified fatty acids may exert a similar inhibitory effect on the transport of glycine. The mechanism for this inhibitory effect has been examined in a plasma membrane vesicle preparation derived from C6 cells, which avoids metabolic or compartmentation interferences. The results suggest that part of the selective inhibition of glycine transport by arachidonic acid could be due to the effects of the arachidonic acid on the lipid domain surrounding the carrier.

scholarly journals Effects of Different Doses of Metformin on Serum Fatty Acid Composition in Type 2 Diabetic Rats

2017 ◽  
Vol 5 (1) ◽  
pp. 22-28
Author(s):  
Nazi Aghaalikhani ◽  
Mohammad Taghi Goodarzi ◽  
Zeinab Latifi ◽  
Azam Rezaei Farimani ◽  
Amir Fattahi
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Unsaturated Fatty Acids ◽  
Serum Insulin ◽  
Diabetic Rats ◽  
Glucose Levels ◽  
Different Doses

Background: Several studies have shown association of fatty acids with type 2 diabetes (T2D), as well as metformin effects on blood glucose concentrations through affecting lipid metabolism. Objectives: Since the exact therapeutic mechanism of metformin is not clear, in this study we investigated effects of different doses of metformin on serum fatty acids in rats with T2D. Materials and Methods: Twenty-five adult albino male Wistar rats were divided into the following groups: Healthy, untreated T2D, and T2D rats receiving metformin for 4 weeks with doses of 100, 150, and 200 mg/kg/d. Serum insulin and triglyceride (TG) were measured using commercial kits. Serum total lipids were extracted by the Bligh-Dyer method and then compositions of fatty acids were evaluated using gas chromatograph. Results: Monounsaturated fatty acid (MUFA) levels in T2D rats were lower than those in healthy rats (P < 0.05). We also observed that diabetic rats treated with 100 or 150 mg/kg/d of metformin had higher levels of arachidonic acid and polyunsaturated fatty acids (PUFA) in comparison with the healthy group (P < 0.05). Moreover, the T2D+Met (150 mg/kg) group showed increased levels of MUFA compared with the T2D group. Such a difference was seen in levels of arachidonic acid between the T2D+Met 100 mg/ kg group and untreated T2D group. In the group treated with high doses of metformin (200 mg/kg/d), levels of palmitic acid, palmitoleic acid, and saturated fatty acid (SFA) were higher and levels of oleic acid, linoleic acid, arachidonic acid, MUFA, PUFA, and also SFA/UFA ratio were lower compared with other metformin treated and untreated groups (P < .05). In untreated T2D group, there were positive correlations between glucose levels and linoleic acid and PUFA levels (r = 0.707, P = .049 and r = 0.726, P = .041 respectively). Arachidonic acid levels were positively correlated with glucose levels in T2D rats treated with 100 mg/kg/d of metformin (r = 0.969, P = .031). Conclusions: Our study showed that different doses of metformin could have different effects on serum levels of saturated and unsaturated fatty acids, as 200 mg/kg/d of metformin could increase and decrease saturated and unsaturated fatty acids respectively, while lower doses increased unsaturated fatty acids, particularly arachidonic acid.

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.

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