scholarly journals Suppression of progesterone-enhanced hyperactivation in hamster spermatozoa by estrogen

Reproduction ◽  
2010 ◽  
Vol 140 (3) ◽  
pp. 453-464 ◽  
Author(s):  
Masakatsu Fujinoki
Keyword(s):  
Steroid Hormones ◽  
Sperm Head ◽  
The Other ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Other Hand ◽  
Sperm Proteins ◽  
17Β Estradiol

In this study, I examined whether sperm hyperactivation in hamster is regulated by steroid hormones such as estrogen (estradiol, E2) and progesterone. Although sperm hyperactivation was enhanced by progesterone, 17β-estradiol (17βE2) itself did not affect sperm hyperactivation. However, 17βE2 suppressed progesterone-enhanced hyperactivation in a concentration-dependent manner through non-genomic pathways when spermatozoa were exposed to 17βE2 at the same time or before exposure to progesterone. When spermatozoa were exposed to 17βE2 after exposure to progesterone, 17βE2 did not suppress progesterone-enhanced hyperactivation. Moreover, 17α-estradiol, an inactive isomer of E2, did not suppress progesterone-enhanced hyperactivation. Observations using a FITC-conjugated 17βE2 showed that it binds to the acrosome region of the sperm head. Binding of 17βE2 to spermatozoa was not inhibited by progesterone, although 17βE2 did not suppress progesterone-enhanced hyperactivation when spermatozoa were exposed to 17βE2 after exposure to progesterone. On the other hand, binding of progesterone to spermatozoa was also not inhibited by 17βE2 even if progesterone-enhanced hyperactivation was suppressed by 17βE2. Although tyrosine phosphorylations of sperm proteins were enhanced by progesterone, enhancement of tyrosine phosphorylations by progesterone was suppressed by 17βE2. Moreover, tyrosine phosphorylations were inhibited by 17βE2 when only 17βE2 was added to the medium. From these results, it is likely that 17βE2 competitively suppresses progesterone-enhanced hyperactivation through the inhibition of tyrosine phosphorylations via non-genomic pathways.

scholarly journals Antiausterity Activity of Arctigenin Enantiomers: Importance of (2R,3R)-Absolute Configuration

2014 ◽  
Vol 9 (1) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Suresh Awale ◽  
Mamoru Kato ◽  
Dya Fita Dibwe ◽  
Feng Li ◽  
Chika Miyoshi ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Cancer Cells ◽  
Absolute Configuration ◽  
The Other ◽  
Dependent Manner ◽  
Meoh Extract ◽  
Concentration Dependent Manner ◽  
Akt Activation ◽  
Other Hand

From a MeOH extract of powdered roots of Wikstroema indica, six dibenzyl-γ-butyrolactone-type lignans with (2 S,3 S)-absolute configuration [(+)-arctigenin (1), (+)-matairesinol (2), (+)-trachelogenin (3), (+)-nortrachelogenin (4), (+)-hinokinin (5), and (+)-kusunokinin (6)] were isolated, whereas three dibenzyl-γ-butyrolactone-type lignans with (2 R,3 R)-absolute configuration [(-)-arctigenin (1), (-)-matairesinol (2), (-)-trachelogenin (3)] were isolated from Trachelospermum asiaticum. The in vitro preferential cytotoxic activity of the nine compounds was evaluated against human pancreatic PANC-1 cancer cells in nutrient-deprived medium (NDM), but none of the six lignans (1–6) with (2 S,3 S)-absolute configuration showed preferential cytotoxicity. On the other hand, three lignans (1*–3*) with (2 R,3 R)-absolute configuration exhibited preferential cytotoxicity in a concentration-dependent manner with PC50 values of 0.54, 6.82, and 5.85 μM, respectively. Furthermore, the effect of (-)- and (+)-arctigenin was evaluated against the activation of Akt, which is a key process in the tolerance to nutrition starvation. Interestingly, only (-)-arctigenin (1*) strongly suppressed the activation of Akt. These results indicate that the (2 R,3 R)-absolute configuration of (-)-enantiomers should be required for the preferential cytotoxicity through the inhibition of Akt activation.

Serotonin relaxes porcine pial veins

1994 ◽  
Vol 266 (3) ◽  
pp. H1000-H1006 ◽  
Author(s):  
T. J. Lee ◽  
M. Ueno ◽  
N. Sunagane ◽  
M. H. Sun
Keyword(s):  
Muscle Tone ◽  
The Other ◽  
Receptor Subtypes ◽  
Dependent Manner ◽  
Pial Arteries ◽  
Concentration Dependent Manner ◽  
Vasoactive Substances ◽  
Other Hand ◽  
Mechanical Stretching ◽  
Or Applications

The effect of serotonin [5-hydroxytryptamine (5-HT)] on pial venous tone of the pig was examined using in vitro tissue bath techniques. Isolated pial venous rings exhibited spontaneous rhythmic contractions (SRC) on mechanical stretching and/or applications of several vasoactive substances, including norepinephrine. On the other hand, KCl induced sustained active muscle tone (SAT) without SRC. The SRC induced by mechanical stretching were not affected by tetrodotoxin, nitro-L-arginine, alpha- and beta-adrenergic, histaminergic, and muscarinic receptor antagonists, indicating that the SRC in porcine pial veins are of myogenic origin. The SRC induced by stretching or applications of vasoactive substances and SAT induced by KCl were inhibited by 5-HT in a concentration-dependent manner. The inhibition was prevented by methysergide and methiothepin but not by ketanserin, propranolol, 3 alpha-tropanyl-1H-indole-3-carboxylic acid ester, hemoglobin, or nitro-L-arginine. The SRC and SAT were inhibited by 5-carboxamidotryptamine (5-CT), 8-hydroxy-2-di-N-propylaminotetralin HBr (8-OHDPAT), 1-[3-(trifluoromethyl)phenyl]piperazine (TFMPP), and 5-methoxytryptamine (5-MT), but not by sumatriptan, alpha-methylserotonin, or 2-methylserotonin. On the other hand, 5-CT, 8-OHDPAT, TFMPP, 5-MT, and sumatriptan constricted the porcine pial arteries exclusively. In 15% of pial venous preparations examined, 5-HT at low concentrations induced ketanserin-sensitive constrictions. These results indicate that the porcine pial venous smooth muscle contains multiple subtypes of 5-HT receptors. The 5-HT inhibition of SRC and SAT is predominant and is mediated by 5-HT1-like receptors, which, however, do not seem to correspond to 5-HT1A, 5-HT1B, 5-HT1C, 5-HT1D, 5-HT1E, or 5-HT1F receptor subtypes.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Antioxidant and Prooxidant Effects of Metal Dafonates on the NADPH-Dependent Lipid Peroxidation in the Murine Hepatic Microsomal System

1999 ◽  
Vol 6 (3) ◽  
pp. 169-175 ◽  
Author(s):  
M. Gupta ◽  
R. K. Kale ◽  
P. P. Kulkarni ◽  
S. B. Padhye
Keyword(s):  
Lipid Peroxidation ◽  
Metal Ions ◽  
The Other ◽  
Inhibition Constant ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Other Hand ◽  
Significant Reversal

Dafone inhibits the lipid peroxidation significantly in a concentration dependent manner. The inhibition was found to be an uncompetitive type with the inhibition constant (Ki) of 62.5 μM On the other hand complexation with metal ions results in a significant reversal from antioxidant to pro-oxidant properties for the resulting complexes which are cationic and with associated halometallate anions. The nature of the potentiation in case of the ferric compound was of competitive type with activation constant (Ka) having the value 32.5 μM . The neutral copper-dafonate complex, however, inhibits lipid peroxidation with increase in concentration.

scholarly journals Antispasmodic effect of hydroalcoholic and flavonoids extracts of Dracocephalum kotschyi on rabbit bladder

2020 ◽  
Vol 9 (2) ◽  
pp. 145-152
Author(s):  
Hassan Sadraei ◽  
Seyed Ebrahim Sajjadi ◽  
Arefe Tarafdar
Keyword(s):  
Smooth Muscle ◽  
The Other ◽  
Organ Bath ◽  
Dependent Manner ◽  
Bladder Smooth Muscle ◽  
Concentration Dependent Manner ◽  
Standard Drug ◽  
Other Hand ◽  
Dracocephalum Kotschyi ◽  
Rabbit Bladder

Introduction: Dracocephalum kotschyi extract has antispasmodic activities on smooth muscle including ileum, uterus and trachea. The objective of this research was to investigate antispasmodic activity of hydroalcoholic and flavonoids extracts of D. kotschyi on rabbit bladder contractions. Methods: Rabbits were euthanized by carbon dioxide asphyxiation and the whole bladder was dissected out and immersed in the Tyrode’s solution. Longitudinal bladder strips were mounted vertically in an organ bath at 37°C and gassed continuously with O2 . Bladder strips were contracted with acetylcholine (ACh), KCl, or electrical field stimulation (EFS). Isotonic tension of the tissue was recorded before and after addition of hydroalcoholic or flavonoids rich extracts of D. kotschyi. Nifedipine and propantheline were used as standard drugs. Results: Standard drug propantheline, prevented bladder phasic contraction induced by ACh (1µM) without affecting KCl response. On the other hand, cumulative addition of nifedipine attenuated the tonic contractions induced by KCl (20mM) on bladder smooth muscle. Hydroalcoholic and flavonoids extracts of D. kotschyiat concentration ranges of 10-320 µg/ mL in a concentration dependent way inhibited bladder tonic contraction induced by KCl (n=6). Both extracts also in a concentration-dependent manner relaxed EFS and ACh-induced contractions (range, 20–1280 µg/mL) of bladder smooth muscle in vitro. Complete inhibition was achieved with the highest used concentrations of the extracts. The inhibitory effect of the extract was reversible following washing the tissues with fresh Tyrode’s solution. Conclusion: This study clearly demonstrated that D. kotschyi extracts were able to prevent contractions induced by ACh, KCl or EFS in isolated rabbit bladder. This means that people consuming this medicinal plant may face urinary retention which could be a problem for patients with prostate hypertrophy. On the other hand, this plant might be useful in patients with urinary incontinence. However, its usefulness must be assessed in the controlled clinical trials.

scholarly journals Metal Ions in Activated Carbon Improve the Detection Efficiency of Aflatoxin-Producing Fungi

Toxins ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 140 ◽  
Author(s):  
Tadahiro Suzuki ◽  
Masatoshi Toyoda
Keyword(s):  
Activated Carbon ◽  
Metal Ions ◽  
Detection Efficiency ◽  
Trace Element Analysis ◽  
The Other ◽  
Dependent Manner ◽  
Element Analysis ◽  
Concentration Dependent Manner ◽  
Key Factor ◽  
Co Addition

Aflatoxins (AF), produced by several Aspergillus species, are visible under ultraviolet light if present in high amounts. AF detection can be improved by adding activated carbon, which enhances the observation efficiency of weakly AF-producing fungi. However, commercial activated carbon products differ in their characteristics, making it necessary to investigate which characteristics affect method reproducibility. Herein, the addition of 10 activated carbon products resulted in different AF production rates in each case. The differences in the production of aflatoxin G1 (AFG1) were roughly correlated to the observation efficiency in the plate culture. Trace element analysis showed that the concentrations of several metal ions differed by factors of >100, and the carbons that most effectively increased AFG1 production contained higher amounts of metal ions. Adding 5 mg L−1 Fe or Mg ions increased AFG1 production even without activated carbon. Furthermore, co-addition of both ions increased AFG1 production stably with the addition of carbon. When varying the concentration of additives, only AFG1 production increased in a concentration-dependent manner, while the production of all the other AFs decreased or remained unchanged. These findings suggest that a key factor influencing AF production is the concentration of several metal ions in activated carbon and that increasing AFG1 production improves AF detectability.

scholarly journals Inhibitory effect of Sphagnum palustre extract and its bioactive compounds on aromatase activity

2016 ◽  
Vol 11 (3) ◽  
pp. 661
Author(s):  
Hee Jeong Eom ◽  
Yong Joo Park ◽  
Hee Rae Kang ◽  
Ha Ryong Kim ◽  
In Jae Bang ◽  
...  
Keyword(s):  
Video Clip ◽  
Inhibitory Effect ◽  
The Other ◽  
Aromatase Activity ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Aromatase Inhibition ◽  
Concentration Dependent Manner ◽  
Cardiac Pain ◽  
Sphagnum Palustre

<p><em>Sphagnum palustre</em> (a moss) has been traditionally used in Korea for the cure of several diseases such as cardiac pain and stroke. In this research, the inhibitory effect of <em>S. palustre</em> on aromatase (cytochrome P<sub>450</sub> 19, CYP19) activity was studied. [1β-<sup>3</sup>H] androstenedione was used as a substrate and incubated with <em>S. palustre</em> extract and recombinant human CYP19 in the presence of NADPH. <em>S. palustre</em> extract inhibited aromatase in a concentration-dependent manner (IC<sub>50</sub> value: 36.4 ± 8.1 µg/mL). To elucidate the major compounds responsible for the aromatase inhibitory effects of <em>S. palustre</em> extract, nine compounds were isolated from the extract and tested for their inhibition of aromatase activity. Compounds <strong>1</strong>, <strong>6</strong>, and <strong>7</strong> displayed aromatase inhibition, while the inhibition by the other compounds was negligible.</p><p><strong>Video Clip</strong></p><p><a href="https://youtube.com/v/n6xeo3RXJVY">Aromatase enzyme activity:</a> 4 min 16 sec  </p>

scholarly journals Comparative Intracellular (THP-1 Macrophage) and Extracellular Activities of β-Lactams, Azithromycin, Gentamicin, and Fluoroquinolones against Listeria monocytogenes at Clinically Relevant Concentrations

2002 ◽  
Vol 46 (7) ◽  
pp. 2095-2103 ◽  
Author(s):  
Stéphane Carryn ◽  
Françoise Van Bambeke ◽  
Marie-Paule Mingeot-Leclercq ◽  
Paul M. Tulkens
Keyword(s):  
Listeria Monocytogenes ◽  
Conventional Therapy ◽  
The Other ◽  
Intracellular Bacteria ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cellular Accumulation ◽  
Intracellular Activities ◽  
The Difference ◽  
In Cells

ABSTRACT The activities of ampicillin, meropenem, azithromycin, gentamicin, ciprofloxacin, and moxifloxacin against intracellular hemolysin-positive Listeria monocytogenes were measured in human THP-1 macrophages and were compared with the extracellular activities observed in broth. All extracellular concentrations were adjusted to explore ranges that are clinically achievable in human serum upon conventional therapy. In broth, ampicillin, meropenem, and azithromycin were only bacteriostatic, whereas gentamicin, ciprofloxacin, and moxifloxacin were strongly bactericidal in a concentration-dependent manner. In cells, ampicillin, meropenem, azithromycin, and ciprofloxacin were slightly bactericidal (0.3- to 0.8-log CFU reductions), moxifloxacin was strongly bactericidal (2.1-log CFU reduction), and gentamicin was virtually inactive. The difference in the efficacies of moxifloxacin and ciprofloxacin in cells did not result from a difference in levels of accumulation in cells (6.96 ± 1.05 versus 7.75 ± 1.03) and was only partially explainable by the difference in the MICs (0.58 ± 0.04 versus 1.40 ± 0.17 mg/liter). Further analysis showed that intracellular moxifloxacin expressed only approximately 1/7 of the activity demonstrated against extracellular bacteria and ciprofloxacin expressed only 1/15 of the activity demonstrated against extracellular bacteria. Gentamicin did not increase the intracellular activities of the other antibiotics tested. The data suggest (i) that moxifloxacin could be of potential interest for eradication of the intracellular forms of L. monocytogenes, (ii) that the cellular accumulation of an antibiotic is not the only determinant of its intracellular activity (for fluoroquinolones, it is actually a self-defeating process as far as activity is concerned), and (iii) that pharmacodynamics (activity-to-concentration relationships) need to be considered for the establishment of efficacy against intracellular bacteria, just as they are for the establishment of efficacy against extracellular infections.

Modification of intracellular calcium concentration in cardiomyocytes by inhibition of sarcolemmal Na+/H+ exchanger

2006 ◽  
Vol 291 (6) ◽  
pp. H2790-H2800 ◽  
Author(s):  
Harjot K. Saini ◽  
Naranjan S. Dhalla
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Intracellular Calcium ◽  
Calcium Concentration ◽  
Extracellular Ph ◽  
The Other ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Rat Cardiomyocytes ◽  
Intracellular Ca ◽  
Isolated Rat

Although the Na+/H+ exchanger (NHE) is considered to be involved in regulation of intracellular Ca2+ concentration ([Ca2+]i) through the Na+/Ca2+ exchanger, the exact mechanisms of its participation in Ca2+ handling by cardiomyocytes are not fully understood. Isolated rat cardiomyocytes were treated with or without agents that are known to modify Ca2+ movements in cardiomyocytes and exposed to an NHE inhibitor, 5-( N-methyl- N-isobutyl)amiloride (MIA). [Ca2+]i in cardiomyocytes was measured spectrofluorometrically with fura 2-AM in the absence or presence of KCl, a depolarizing agent. MIA increased basal [Ca2+]i and augmented the KCl-induced increase in [Ca2+]i in a concentration-dependent manner. The MIA-induced increase in basal [Ca2+]i was unaffected by extracellular Ca2+, antagonists of the sarcolemmal (SL) L-type Ca2+ channel, and inhibitors of the SL Na+/Ca2+ exchanger, SL Ca2+ pump ATPase and mitochondrial Ca2+ uptake. However, the MIA-induced increase in basal [Ca2+]i was attenuated by inhibitors of SL Na+-K+-ATPase and sarcoplasmic reticulum (SR) Ca2+ transport. On the other hand, the MIA-mediated augmentation of the KCl response was dependent on extracellular Ca2+ concentration and attenuated by agents that inhibit SL L-type Ca2+ channels, the SL Na+/Ca2+ exchanger, SL Na+-K+-ATPase, and SR Ca2+ release channels and the SR Ca2+ pump. However, the effect of MIA on the KCl-induced increase in [Ca2+]i remained unaffected by treatment with inhibitors of SL Ca2+ pump ATPase and mitochondrial Ca2+ uptake. MIA and a decrease in extracellular pH lowered intracellular pH and increased basal [Ca2+]i, whereas a decrease in extracellular pH, in contrast to MIA, depressed the KCl-induced increase in [Ca2+]i in cardiomyocytes. These results suggest that NHE may be involved in regulation of [Ca2+]i and that MIA-induced increases in basal [Ca2+]i, as well as augmentation of the KCl-induced increase in [Ca2+]i, in cardiomyocytes are regulated differentially.

scholarly journals Block of current through single calcium channels by Fe, Co, and Ni. Location of the transition metal binding site in the pore.

1991 ◽  
Vol 97 (2) ◽  
pp. 351-367 ◽  
Author(s):  
B D Winegar ◽  
R Kelly ◽  
J B Lansman
Keyword(s):  
Metal Binding ◽  
The Other ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Coulombic Interactions ◽  
Rate Limiting Step ◽  
Ion Size ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Ca2 Channels

The blocking actions of Fe2+, Co2+, and Ni2+ on unitary currents carried by Ba2+ through single dihydropyridine-sensitive Ca2+ channels were recorded from cell-attached patches on myotubes from the mouse C2 cell line. Adding millimolar concentrations of blocker to patch electrodes containing 110 mM BaCl2 produced discrete excursions to the closed channel level. The kinetics of blocking and unblocking were well described with a simple model of open channel block. Hyperpolarization speeded the exit of all of the blockers from the channel, as expected if the blocking site resides within the pore. The block by Ni2+ differs from that produced by Fe2+ and Co2+ because Ni2+ enters the channel approximately 20 times more slowly and exits approximately 50 times more slowly. Ni2+ also differs from the other transition metals because at millimolar concentrations it reduces the amplitude of the unitary current in a concentration-dependent manner. The results are consistent with the idea that the rate-limiting step for ion entry into the channel is water loss at its inner coordination sphere; unblocking, on the other hand, cannot be explained in terms of simple coulombic interactions arising from differences in ion size.

Effects of Trehalose and Ethanol on Yeast Cytosolic Pyrophosphatase

1999 ◽  
Vol 54 (3-4) ◽  
pp. 186-190 ◽  
Author(s):  
Dahabada Helena José Lopes ◽  
José Roberto Meyer-Fernandes ◽  
Mauro Sola-Penna
Keyword(s):  
Fermentation Process ◽  
Stress Condition ◽  
The Other ◽  
Dependent Manner ◽  
Control Activity ◽  
Other Hand ◽  
Ethanol Ethanol ◽  
Stress Protectant ◽  
Dose Dependent

Trehalose has been described to protect several enzymes against destabilizing conditions. This sugar is naturally accumulated by yeast as a stress protectant. A common stress condition that yeast is normally submitted is the presence of ethanol, the by-product of fermentation process of several yeast. In this paper we show the effects of trehalose and ethanol, alone or together, on yeast pyrophosphatase, and the effects of these compounds on inhibition and unfolding of pyrophosphatase promoted by urea. We show that both trehalose and ethanol inhibit pyrophosphatase in a dose-dependent manner, and that the presence of ethanol does not modify the inhibition promoted by trehalose as well as the presence of trehalose does not modify the inhibition promoted by ethanol. The effects of trehalose on pyrophosphatase are completely reversible, but the inhibition caused by ethanol was only partially reversible. Incubation of pyrophosphatase with 10% (v/v) ethanol promoted an inhibition of 15%, and the control activity was completely recovered after removal of ethanol. On the other hand, when pyrophosphatase was incubated with 20% (v/v) ethanol an inhibition of 40% of the control activity was observed which persisted after removal of ethanol. Ethanol also potentiates the inhibition of pyrophosphatase promoted by urea, and contributes for an irreversible inactivation and unfolding of pyrophosphatase in the presence of urea. Trehalose, that protects this enzyme against the inhibition and unfolding promoted by the chaotropic compound urea, was inefficient to protect against the effects of ethanol. Trehalose was also efficient to prevent an irreversible inactivation induced by urea.

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