scholarly journals Non-enzymatically oxidized arachidonic acid regulates mouse spermatogenic cell T-type Ca2+currents

2019 ◽  
Author(s):  
O. Bondarenko ◽  
G. Corzo ◽  
F.L. Santana ◽  
F. del Río-Portilla ◽  
A. Darszon ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Plasma Membranes ◽  
Present Report ◽  
Spermatogenic Cell ◽  
Spermatogenic Cells ◽  
Membrane Phospholipids ◽  
Biophysical Parameters ◽  
Germ Cell Line ◽  
Cell Plasma ◽  
Steady State Inactivation

ABSTRACTDuring spermatogenesis, phospholipids and fatty acids (FAs) play an important role both as structural components of spermatogenic cell plasma membranes and as molecular messengers that trigger the differentiation of the male germ cell line. However, spontaneous oxidation of plasma membrane phospholipids and FAs causes a decrease in mammalian fertility. In the present report, we examine the effects of non-enzymatically oxidized arachidonic acid (AAox) on mouse spermatogenic T-type Ca2+currents (ICaT) due to their physiological relevance during spermatogenesis. AAoxeffects on the biophysical parameters of ICaTwere significantly different from those previously reported for AA. AAoxleft shifted the I-V curve peak and both activation and steady-state inactivation curves. ICaTdeactivation kinetics were slower in presence of AAoxand the time for its recovery from inactivation increased significantly. Therefore, the fraction of inactivated Ca2+channels of spermatogenic cells is increased at voltages where they are usually active. The inhibition of ICaTby AAoxcould contribute to the infertility phenotype and to the observed apoptotic state of spermatogenic cells induced by oxidized FAs.

In vitro effect of free bile acids on the bile canaliular membrane phospholipids in the rat

1976 ◽  
Vol 54 (12) ◽  
pp. 1040-1046 ◽  
Author(s):  
I. M. Yousef ◽  
M. M. Fisher
Keyword(s):  
Bile Acid ◽  
Plasma Membranes ◽  
Membrane Phospholipid ◽  
Male Rats ◽  
Membrane Phospholipids ◽  
Experimental Conditions ◽  
Cell Plasma ◽  
Vitro Effect ◽  
Free Bile Acids

Liver cell plasma membranes of male rats were isolated and separated into two fractions, one rich in bile canalicular membranes (BCM) and the other comprising the rest of the plasma membranes (PM). Aliquots of BCM, PM, and microsomes were incubated with deoxycholic, chenodeoxycholic, or cholic acid at bile acid – membrane phospholipid mole ratios up to 100, and the phospholipids solubilized from the membranes were analyzed.Phospholipid solubilization from the PM and from microsomes was linear and apparently nonselective, while that from the BCM was biphasic and distinctly selective. Phosphatidyl choline and phosphatidyl ethanolamine made up 90% of the phospholipids solubilized from the BCM at a bile acid – membrane phospholipid mole ratio sufficient to solubilize about 50% of the total phospholipids of the BCM. Of particular interest was the observation that the molecular species and fatty acid composition of the phospholipids solubilized from the BCM under these experimental conditions were similar to those of bile obtained from the same animal, and were quite unlike those solubilized at higher bile acid – phospholipid mole ratios. The data are discussed in terms of the mechanism of the biliary secretion of phospholipids.

Mechanism of hypoxic injury to pulmonary artery endothelial cell plasma membranes

1989 ◽  
Vol 257 (2) ◽  
pp. C223-C231 ◽  
Author(s):  
E. R. Block ◽  
J. M. Patel ◽  
D. Edwards
Keyword(s):  
Fatty Acids ◽  
Plasma Membrane ◽  
Endothelial Cell ◽  
Pulmonary Artery ◽  
Lipid Composition ◽  
Plasma Membranes ◽  
Membrane Lipid ◽  
Conjugated Dienes ◽  
Membrane Phospholipids ◽  
Cell Plasma

We exposed monolayer cultures of pulmonary artery endothelial cells or plasma membranes derived from these cells to hypoxic (0 and 5% O2) and normoxic (20% O2; control) conditions and measured cellular contents of malondialdehyde and conjugated dienes, plasma membrane fluidity and lipid composition, and plasma membrane-dependent transport of 5-hydroxytryptamine (5-HT). Hypoxia caused significant increases in malondialdehyde and conjugated dienes, in fluidity, and in 5-HT transport. Hypoxia also caused a significant decrease in plasma membrane total phospholipids and a marked increase in plasma membrane free fatty acids that appeared to be due to release of fatty acids from the plasma membrane phospholipids. The increases in fluidity and 5-HT transport and the alterations in fatty acids were reversible after return to control conditions. These results indicate that hypoxia alters the physical state, lipid composition, and function of endothelial cell plasma membranes by a combination of stimulation of membrane lipid peroxidation and accelerated degradation of membrane phospholipids, the latter probably secondary to activation of membrane phospholipases.

Annulate lamellae in the Sertoli cells of guinea pig testis after unilateral torsion of the spermatic cord

1984 ◽  
Vol 42 ◽  
pp. 196-197
Author(s):  
J. Chakraborty ◽  
A. P. Sinha Hikim ◽  
J. S. Jhunjhunwala
Keyword(s):  
Sertoli Cells ◽  
Guinea Pigs ◽  
Spermatic Cord ◽  
Present Report ◽  
Cell Types ◽  
Annulate Lamellae ◽  
Spermatogenic Cells ◽  
Electron Microscopic ◽  
Structural Details ◽  
First Time

Although the presence of annulate lamellae was noted in many cell types, including the rat spermatogenic cells, this structure was never reported in the Sertoli cells of any rodent species. The present report is based on a part of our project on the effect of torsion of the spermatic cord to the contralateral testis. This paper describes for the first time, the fine structural details of the annulate lamellae in the Sertoli cells of damaged testis from guinea pigs.One side of the spermatic cord of each of six Hartly strain adult guinea pigs was surgically twisted (540°) under pentobarbital anesthesia (1). Four months after induction of torsion, animals were sacrificed, testes were excised and processed for the light and electron microscopic investigations. In the damaged testis, the majority of seminiferous tubule contained a layer of Sertoli cells with occasional spermatogonia (Fig. 1). Nuclei of these Sertoli cells were highly pleomorphic and contained small chromatinic clumps adjacent to the inner aspect of the nuclear envelope (Fig. 2).

Interaction between cortisol and arachidonic acid on the secretion of LH from ovine pituitary tissue

1991 ◽  
Vol 131 (1) ◽  
pp. 87-94 ◽  
Author(s):  
A. W. Nangalama ◽  
G. P. Moberg
Keyword(s):  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Suppressive Effect ◽  
Inhibitory Effect ◽  
Adrenal Steroids ◽  
Membrane Phospholipids ◽  
Pituitary Tissue ◽  
Receptor Sites ◽  
Lh Release ◽  
Gonadotrophin Releasing Hormone

ABSTRACT In several species, glucocorticoids act directly on the pituitary gonadotroph to suppress the gonadotrophin-releasing hormone (GnRH)-induced secretion of the gonadotrophins, especially LH. A mechanism for this action of these adrenal steroids has not been established, but it appears that the glucocorticoids influence LH release by acting on one or more post-receptor sites. This study investigated whether glucocorticoids disrupt GnRH-induced LH release by altering the liberation of arachidonic acid from plasma membrane phospholipids, a component of GnRH-induced LH release. Using perifused ovine pituitary tissue, it was established that exposure of gonadotrophs to 1–1000 nmol cortisol/l for 4 h or longer significantly reduced GnRH-stimulated LH release with the maximal inhibitory effect being observed after 6 h of exposure to cortisol. This suppressive effect of cortisol could be reversed by administration of arachidonic acid, which in its own right could stimulate LH release from ovine pituitary tissue. Furthermore, the inhibitory effect of cortisol on GnRH-stimulated LH release could be directly correlated with decreased pituitary responsiveness to GnRH-stimulated arachidonic acid liberation, consistent with our hypothesis that glucocorticoids can suppress GnRH-induced secretion of LH by reducing the amount of arachidonic acid available for the exocytotic response of GnRH. Journal of Endocrinology (1991) 131, 87–94

scholarly journals Insulin-induced rapid decrease of a major protein in fat cell plasma membranes.

1984 ◽  
Vol 259 (19) ◽  
pp. 12112-12116
Author(s):  
E J Schoenle ◽  
L D Adams ◽  
D W Sammons
Keyword(s):  
Plasma Membranes ◽  
Rapid Decrease ◽  
Major Protein ◽  
Fat Cell ◽  
Cell Plasma

scholarly journals Acute Nicotine Reduces Brain Arachidonic Acid Signaling in Unanesthetized Rats

2009 ◽  
Vol 29 (3) ◽  
pp. 648-658 ◽  
Author(s):  
Lisa Chang ◽  
Stanley I Rapoport ◽  
Henry N Nguyen ◽  
Dede Greenstein ◽  
Mei Chen ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Brain Regions ◽  
Membrane Phospholipids ◽  
Dose Equivalent ◽  
Central Effects ◽  
Postsynaptic Receptors ◽  
Cytosolic Phospholipase ◽  
Presynaptic Release

Nicotine exerts its central effects by activating pre- and postsynaptic nicotinic acetylcholine receptors (nAChRs). Presynaptic nAChRs modulate the release of many neurotransmitters that bind to postsynaptic receptors. These may be coupled to the activation of cytosolic phospholipase A2 (cPLA2), which hydrolyzes arachidonic acid (AA) from membrane phospholipids. We hypothesized that nicotine would modify brain signaling involving AA by binding to nAChRs. Nicotine (0.1 mg/kg, subcutaneously) or saline was injected 2 or 10 mins before infusing [1-14C]AA in unanesthetized rats. The AA incorporation coefficient k∗ (a marker of the AA signal) was measured in 80 brain regions by quantitative autoradiography. Nicotine, compared to saline, when administrated 2 mins before [1-14C]AA infusion, significantly decreased k∗ for AA in 26 regions, including cerebral cortex, thalamus, and habenula—interpeduncular regions, by 13% to 45%. These decreases could be entirely prevented by pretreatment with mecamylamine (1.0 mg/kg, subcutaneously). When administered 10 mins before [1-14C]AA infusion, nicotine did not alter any value of k∗. In summary, nicotine given to unanesthetized rats rapidly reduces signaling involving AA in brain regions containing nAChRs, likely by modulating the presynaptic release of neurotransmitters. The effect shows rapid desensitization and is produced at a nicotine dose equivalent to smoking one cigarette in humans.

scholarly journals Charged anaesthetics alter LM-fibroblast plasma-membrane enzymes by selective fluidization of inner or outer membrane leaflets

1986 ◽  
Vol 239 (2) ◽  
pp. 301-310 ◽  
Author(s):  
W D Sweet ◽  
F Schroeder
Keyword(s):  
Plasma Membrane ◽  
Active Site ◽  
Plasma Membranes ◽  
Local Anaesthetics ◽  
Cationic Drugs ◽  
Cell Plasma ◽  
Composition And Structure ◽  
Highly Sensitive ◽  
Functional Consequences ◽  
Anionic Drugs

The functional consequences of the differences in lipid composition and structure between the two leaflets of the plasma membrane were investigated. Fluorescence of 1,6-diphenylhexa-1,3,5-triene(DPH), quenching, and differential polarized phase fluorimetry demonstrated selective fluidization by local anaesthetics of individual leaflets in isolated LM-cell plasma membranes. As measured by decreased limiting anisotropy of DPH fluorescence, cationic (prilocaine) and anionic (phenobarbital and pentobarbital) amphipaths preferentially fluidized the cytofacial and exofacial leaflets respectively. Unlike prilocaine, procaine, also a cation, fluidized both leaflets of these membranes equally. Pentobarbital stimulated 5′-nucleotidase between 0.1 and 5 mM and inhibited at higher concentrations, whereas phenobarbital only inhibited, at higher concentrations. Cationic drugs were ineffective. Two maxima of (Na+ + K+)-ATPase activation were obtained with both anionic drugs. Only one activation maximum was obtained with both cationic drugs. The maximum in activity below 1 mM for all four drugs clustered about a single limiting anisotropy value in the cytofacial leaflet, whereas there was no correlation between activity and limiting anisotropy in the exofacial leaflets. Therefore, although phenobarbital and pentobarbital below 1 mM fluidized the exofacial leaflet more than the cytofacial leaflet, the smaller fluidization in the cytofacial leaflet was functionally significant for (Na+ + K+)-ATPase. Mg2+-ATPase was stimulated at 1 mM-phenobarbital, unaffected by pentobarbital and slightly stimulated by both cationic drugs at concentrations fluidizing both leaflets. Thus the activity of (Na+ + K+)-ATPase was highly sensitive to selective fluidization of the leaflet containing its active site, whereas the other enzymes examined were little affected by fluidization of either leaflet.

scholarly journals A rapid immunological procedure for the isolation of hormonally sensitive rat fat-cell plasma membrane

1976 ◽  
Vol 154 (1) ◽  
pp. 11-21 ◽  
Author(s):  
J P Luzio ◽  
A C Newby ◽  
C N Hales
Keyword(s):  
Plasma Membrane ◽  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Membrane Preparation ◽  
Fat Cells ◽  
Fat Cell ◽  
Cell Plasma ◽  
Rat Fat Cells ◽  
Plasma Membrane Preparation ◽  
Isolated Rat

1. A rapid method for the isolation of hormonally sensitive rat fat-cell plasma membranes was developed by using immunological techniques. 2. Rabbit anti-(rat erythrocyte) sera were raised and shown to cross-react with isolated rat fat-cells. 3. Isolated rat fat-cells were coated with rabbit anti-(rat erythrocyte) antibodies, homogenized and the homogenate made to react with an immunoadsorbent prepared by covalently coupling donkey anti-(rabbit globulin) antibodies to aminocellulose. Uptake of plasma membrane on to the immunoadsorbent was monitored by assaying the enzymes adenylate cyclase and 5′-nucleotidase and an immunological marker consisting of a 125I-labelled anti-(immunoglobulin G)-anti-cell antibody complex bound to the cells before fractionation. Contamination of the plasma-membrane preparation by other subcellular fractions was also investigated. 4. By using this technique, a method was developed allowing 25-40% recovery of plasma membrane from fat-cell homogenates within 30 min of homogenization. 5. Adenylate cyclase in the isolated plasma-membrane preparation was stimulated by 5 μm-adrenaline.

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