Dynamic Changes in Spontaneous Intracellular Free Calcium Oscillations and Their Relationship to Prolactin Gene Expression in Single, Primary Mammotropes

1997 ◽  
Vol 12 (1) ◽  
pp. 87-95 ◽  
Author(s):  
C. Villalobos
Keyword(s):  
Gene Expression ◽  
Calcium Oscillations ◽  
Intracellular Free Calcium ◽  
Free Calcium ◽  
Dynamic Changes ◽  
Prolactin Gene

Intracellular free calcium oscillations in normal and cleavage-blocked embryos and artificially activated eggs of Xenopus laevis

1994 ◽  
Vol 107 (8) ◽  
pp. 2229-2237 ◽  
Author(s):  
T.J. Keating ◽  
R.J. Cork ◽  
K.R. Robinson
Keyword(s):  
Xenopus Laevis ◽  
Photon Counting ◽  
Calcium Oscillations ◽  
Intracellular Free Calcium ◽  
Free Calcium ◽  
Counting System ◽  
Normal Medium ◽  
Sinusoidal Oscillations ◽  
Cyclic Changes ◽  
Xenopus Laevis Embryos

We have measured levels of intracellular free calcium ([Ca2+]i) in albino Xenopus laevis embryos using recombinant aequorin and a photon-counting system. We observed sinusoidal oscillations in [Ca2+]i that had the same frequency as cleavage, with cleavage occurring when [Ca2+]i was lowest. An increase in calcium was seen to precede first cleavage. The cyclic changes in calcium were superimposed on a secondary pattern that increased, peaked between third and fifth cleavages and then slowly declined to a level similar to that measured before first cleavage. The amplitude of the oscillations was small during the first few cleavages but became larger with each cycle, with the largest oscillations occurring when the secondary pattern peaked (between third and fifth cleavage). As the secondary pattern declined, the amplitude of the oscillations also became smaller. The oscillations are due to release of calcium from intracellular stores, since the signal was the same in calcium-free solution as in normal medium. When cleavage was blocked with the microtubule-disrupting drugs colchicine or nocodazole, the [Ca2+]i oscillations persisted. Calcium oscillations of a similar magnitude and frequency were also present in artificially activated eggs. The secondary pattern was different in cleavage-blocked embryos and artificially activated eggs, the baseline increasing until about the third cycle and then remaining elevated for the rest of the recording (> 8 hours). By fixing embryos at various points in the calcium cycle, we determined that mitosis began shortly after calcium levels reached their peak and was complete before the calcium level dropped to its lowest point.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Sperm Factor Induces Intracellular Free Calcium Oscillations by Stimulating the Phosphoinositide Pathway1

2001 ◽  
Vol 64 (5) ◽  
pp. 1338-1349 ◽  
Author(s):  
Hua Wu ◽  
Jeremy Smyth ◽  
Veronica Luzzi ◽  
Kiyoko Fukami ◽  
Tadaomi Takenawa ◽  
...  
Keyword(s):  
Calcium Oscillations ◽  
Intracellular Free Calcium ◽  
Free Calcium ◽  
Sperm Factor

189 CHARACTERIZATION OF THE FIRST SPERM-INDUCED CALCIUM TRANSIENT IN PIG OOCYTES

2016 ◽  
Vol 28 (2) ◽  
pp. 225
Author(s):  
C. Wang ◽  
Z. Machaty
Keyword(s):  
Calcium Concentration ◽  
Calcium Transient ◽  
Calcium Oscillations ◽  
Calcium Transients ◽  
Intracellular Free Calcium ◽  
Calcium Signal ◽  
Free Calcium ◽  
Essential Information ◽  
Intracellular Free Calcium Concentration ◽  
Free Calcium Concentration

Fertilization in mammals is associated with repetitive elevations in the oocytes’ intracellular free calcium concentration. The elevations are triggered by the fertilizing sperm and are responsible for stimulating embryo development. In mouse oocytes, the sperm-induced calcium signal starts with a calcium rise that is larger and longer in duration than any succeeding transients. It also has unique characteristics: it begins with a rapid increase for 2–3 s followed by a shoulder, which is an inflection point that represents a brief decline in the rise of calcium levels. Once calcium level reaches its maximum, it decreases but remains elevated for several minutes while it is superimposed by several smaller calcium spikes. In bovine oocytes the situation is somewhat different. In this species, the first sperm-induced calcium transient is larger than the additional spikes but it lacks the sustained elevation phase and is not superimposed by small calcium rises. In the present study our purpose was to characterise the first sperm-induced calcium transient in pig oocytes. Oocytes were obtained from ovaries of prepubertal gilts collected at an abattoir and matured in vitro for 44 h. Mature oocytes were loaded with the calcium indicator dye fura-2; subsequently, they were either IVF or used for intracytoplasmic sperm injection (ICSI). Changes in their intracellular free calcium concentration were then immediately monitored using InCyt Im2, a dual-wavelength fluorescence imaging system. Characteristics of the first transients (including amplitude and duration) were compared to those of the additional ones using Student’s t-test. We found that in oocytes that underwent IVF (n = 11), the oscillations started 83.4 ± 23.2 min after adding the sperm to the oocytes. In the ICSI group (n = 10 oocytes) the calcium oscillations started sooner, 27.1 ± 17.7 min after injection. The average peak amplitude and the mean interval between the calcium transients varied among individual oocytes, but no significant differences were found between the IVF and ICSI groups (which on average were fluorescence ratio of 2.6 ± 1.1 and 23.5 ± 11.4 min, respectively; P > 0.1). The oscillation patterns showed slight differences between individual oocytes in terms of spike frequency, which has been described before and may be due to variations in the amount of sperm-derived activating factor present in the ooplasm. Most importantly, in all oocytes measured, the initial calcium spike showed no differences when compared to subsequent calcium transients: its amplitude and duration was similar to the additional transients. This points at potential species-specific differences in the regulation of calcium signalling in oocytes and provides essential information for the better understanding of the fertilization process. This work was supported by Agriculture and Food Research Initiative Competitive Grant 2011–67015–30006 from the USDA National Institute of Food and Agriculture.

Malathion/Oxon and Lead Acetate Increase Gene Expression and Protein Levels of Transient Receptor Potential Canonical Channel Subunits TRPC1 and TRPC4 in Rat Endothelial Cells of the Blood–Brain Barrier

2012 ◽  
Vol 31 (3) ◽  
pp. 238-249 ◽  
Author(s):  
Pergentino Balbuena ◽  
Wen Li ◽  
Beverly A. Rzigalinski ◽  
Marion Ehrich
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Intracellular Free Calcium ◽  
Free Calcium ◽  
Transient Receptor Potential Canonical ◽  
Protein Levels ◽  
Transient Receptor

This study examined the effects of malathion and lead on transient receptor potential canonical channel TRPC1/TRPC4 channels in rat brain endothelial cells as a mechanism to explain previously noted blood–brain barrier (BBB) permeability induced by these compounds. Lead, malathion, malaoxon and combinations of these were assessed for protein levels and gene expression of TRPC1/C4 at 2, 4, 8, 16, and 24 hours after exposure. Changes in intracellular free calcium dynamics were also assessed. Compounds increased TRPC1 and TRPC4 protein levels as well as gene expression within 4 hours after exposure. Basal levels of intracellular free calcium were also elevated. Increases in gene and protein expression may be associated with an increase in the numbers of TRP channels, and the increases in intracellular calcium may be associated with activation of such channels. Therefore, upregulation and activation of the TRPC1/TRPC4 may be a mechanism by which these neurotoxicants affect BBB permeability.

Benzodiazepines Differentially Inhibit Phenylephrine-induced Calcium Oscillations in Pulmonary Artery Smooth Muscle Cells 

1998 ◽  
Vol 88 (3) ◽  
pp. 792-799 ◽  
Author(s):  
Sung Jin Hong ◽  
Derek S. Damron ◽  
Paul A. Murray
Keyword(s):  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Calcium Oscillations ◽  
Intracellular Free Calcium ◽  
Free Calcium ◽  
Critical Determinant ◽  
Pulmonary Artery Smooth Muscle ◽  
Dose Dependent

Background Modulation of intracellular free calcium is a critical determinant of vasomotor tone. The authors investigated the effects of three benzodiazepines on alpha-adrenergic-induced oscillations in intracellular free calcium in individual pulmonary artery smooth muscle cells. Methods Pulmonary artery smooth muscle cells were cultured from explants of canine intrapulmonary artery. Fura-2-loaded pulmonary artery smooth muscle cells were continuously superfused with phenylephrine (10 microM) at 37 degrees C on the stage of an inverted fluorescence microscope. Intracellular free calcium was measured using a dual wavelength spectrofluorometer. After establishment of steady-state intracellular free calcium oscillations induced by phenylephrine, lorazepam, diazepam, or midazolam was added to the superfusate. The amplitude and frequency of the intracellular free calcium oscillations were compared before and after addition of each agent. Results Resting mean +/- SEM values of intracellular free calcium were 68 +/- 8 nM. Phenylephrine stimulated dose-dependent oscillations in intracellular free calcium, which reached a peak concentration of 676 +/- 35 nM and a frequency of 1.08 +/- 0.1 transients/min. Addition of lorazepam (1 microM) inhibited (P < 0.05) the amplitude (591 +/- 32 nM) but not the frequency (0.97 +/- 0.1 transients/min) of the oscillations. Conversely, diazepam (1 microM) decreased (P < 0.05) the frequency (0.79 +/- 0.1 transients/min) but not the amplitude (663 +/- 37 nM) of the oscillations. These effects were dose-dependent. In contrast, midazolam (1-30 microM) had no effect on the amplitude or frequency of intracellular free calcium oscillations. At concentrations higher than 100 microM, however, all three benzodiazepines inhibited both the amplitude and frequency of the intracellular free calcium oscillations. Conclusion Lorazepam and diazepam but not midazolam exerted differential inhibitory effects on phenylephrine-induced intracellular free calcium oscillations. Benzodiazepines may alter the pulmonary vascular response to sympathetic alpha-adrenoreceptor activation by direct inhibition of intracellular free calcium signaling in pulmonary artery smooth muscle cells.

Dynamic Changes in the Regulation of Energy Balance after Roux-en-Y Gastric Bypass Are Reflected in Time-Dependent Alterations in Liver Gene Expression

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 289-LB
Author(s):  
M. AGOSTINA SANTORO ◽  
JOSEPH BRANCALE ◽  
JILL CARMODY GARRISON ◽  
SRIRAM MACHINENI ◽  
SCOTT A. LAJOIE ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gastric Bypass ◽  
Energy Balance ◽  
Time Dependent ◽  
Dynamic Changes ◽  
Liver Gene

scholarly journals Superoxide anion increases intracellular free calcium in human myometrial cells.

1990 ◽  
Vol 265 (36) ◽  
pp. 22533-22536
Author(s):  
N Masumoto ◽  
K Tasaka ◽  
A Miyake ◽  
O Tanizawa
Keyword(s):  
Superoxide Anion ◽  
Intracellular Free Calcium ◽  
Free Calcium ◽  
Myometrial Cells
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