scholarly journals Depolarization of sperm membrane potential is a common feature of men with subfertility and is associated with low fertilization rate at IVF

2016 ◽  
Vol 31 (6) ◽  
pp. 1147-1157 ◽  
Author(s):  
Sean G. Brown ◽  
Stephen J. Publicover ◽  
Steven A. Mansell ◽  
Polina V. Lishko ◽  
Hannah L. Williams ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Fertilization Rate ◽  
Sperm Membrane

scholarly journals KSper, a pH-sensitive K+ current that controls sperm membrane potential

2007 ◽  
Vol 104 (18) ◽  
pp. 7688-7692 ◽  
Author(s):  
Betsy Navarro ◽  
Yuriy Kirichok ◽  
David E. Clapham
Keyword(s):  
Membrane Potential ◽  
Acrosome Reaction ◽  
Reproductive Tract ◽  
Female Reproductive Tract ◽  
Male Reproductive Tract ◽  
Sperm Flagellum ◽  
K Current ◽  
Sperm Membrane ◽  
Principal Piece ◽  
Mammalian Spermatozoa

Mature mammalian spermatozoa are quiescent in the male reproductive tract. Upon ejaculation and during their transit through the female reproductive tract, they undergo changes that enable them to fertilize the egg. During this process of capacitation, they acquire progressive motility, develop hyperactivated motility, and are readied for the acrosome reaction. All of these processes are regulated by intracellular pH. In the female reproductive tract, the spermatozoan cytoplasm alkalinizes, which in turn activates a Ca2+-selective current (ICatSper) required for hyperactivated motility. Here, we show that alkalinization also has a dramatic effect on membrane potential, producing a rapid hyperpolarization. This hyperpolarization is primarily mediated by a weakly outwardly rectifying K+ current (IKSper) originating from the principal piece of the sperm flagellum. Alkalinization activates the pHi-sensitive IKSper, setting the membrane potential to negative potentials where Ca2+ entry via ICatSper is maximized. IKSper is one of two dominant ion currents of capacitated sperm cells.

scholarly journals ZP3-dependent activation of sperm cation channels regulates acrosomal secretion during mammalian fertilization.

1996 ◽  
Vol 134 (3) ◽  
pp. 637-645 ◽  
Author(s):  
C Arnoult ◽  
Y Zeng ◽  
H M Florman
Keyword(s):  
Membrane Potential ◽  
Pertussis Toxin ◽  
Zona Pellucida ◽  
Mammalian Sperm ◽  
Transient Rise ◽  
Transduction Mechanisms ◽  
Dependent Signal ◽  
Sperm Membrane ◽  
Mammalian Fertilization

The sperm acrosome reaction is a Ca(2+)-dependent secretory event required for fertilization. Adhesion to the egg's zona pellucida promotes Ca2+ influx through voltage-sensitive channels, thereby initiating secretion. We used potentiometric fluorescent probes to determine the role of sperm membrane potential in regulating Ca2+ entry. ZP3, the glycoprotein agonist of the zona pellucida, depolarizes sperm membranes by activating a pertussis toxin-insensitive mechanism with the characteristics of a poorly selective cation channel. ZP3 also activates a pertussis toxin-sensitive pathway that produces a transient rise in internal pH. The concerted effects of depolarization and alkalinization open voltage-sensitive Ca2+ channels. These observations suggest that mammalian sperm utilize membrane potential-dependent signal transduction mechanisms and that a depolarization pathway is an upstream transducing element coupling adhesion to secretion during fertilization.

scholarly journals Mitochondrial Function in Modulating Human Granulosa Cell Steroidogenesis and Female Fertility

2020 ◽  
Vol 21 (10) ◽  
pp. 3592
Author(s):  
Dilip Bhargava Sreerangaraja Urs ◽  
Wen-Han Wu ◽  
Katerina Komrskova ◽  
Pavla Postlerova ◽  
Yung-Feng Lin ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Granulosa Cells ◽  
Mitochondrial Function ◽  
Oocyte Quality ◽  
Fertilization Rate ◽  
Mitochondrial Mass ◽  
Ovarian Endometrioma ◽  
The Relationship ◽  
Estradiol Levels ◽  
Follicular Fluids

Ovarian follicle steroidogenesis associated with embryo quality results in a successful pregnancy. Each follicle consists of an oocyte surrounded by granulosa cells, which secrete several steroid and peptide hormones. Follicles harvested from women who conceived after assisted reproductive therapy (ART) had significantly higher estradiol levels in follicular fluids than the follicles from women who failed to conceive after ART. The higher follicular estradiol levels correlate well with successful fertilization following ART. Mitochondria are the central sites for steroid hormone biosynthesis. The first and rate-limiting step in the biosynthesis of steroid hormones occurs in the mitochondria of granulosa cells. In the present study, we hypothesized that the mitochondria in granulosa cells are critical for maintaining oocyte quality and fertility capacity. This study aims to clarify the relationship between mitochondrial function and granulosa cell steroidogenesis, and the relationship between hormone levels and fertility capacity. Sera, follicular fluids and granulosa cells were obtained from individuals undergoing IVF-ET treatment. The oocyte numbers, oocyte quality, fertilization rate, and pregnancy rate were also recorded. The patients who provided the granulosa cells were further classified into four groups: endometriosis, ovarian endometrioma, endometriosis without ovarian endometrioma, and polycystic ovary syndrome (PCOS); patients with other female factor infertility and male factor infertility were used as controls. We measured the levels of estradiol (E2) by radioimmunoassay. Concurrently, we analyzed the mitochondrial mass and membrane potential, and apoptosis by flow cytometry using nonyl acridine orange, TMRE, Annexin V-FITC and PI. Mitochondrial morphology was visualized by transfection with pLV-mitoDsRed. In addition, we assessed the protein levels of steroidogenic enzymes, steroidogenic acute regulatory protein (StAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) by Western blot. The results showed significantly decreased serum E2 and follicular E2 levels, and decreased IVF outcomes, in the patients with endometriosis. Reduced mitochondrial mass and decreased mitochondrial membrane potential were correlated with lower E2. Furthermore, a significant decrease in StAR and 3β-HSD was found in patients with ovarian endometrioma. The enzyme levels of StAR and 3β-HSD were highly correlated with E2 levels. Finally, elevated cumulus cell apoptosis was found in the patient group with ovarian endometrioma and PCOS. In conclusion, mitochondrial dysfunction of human granulosa cells may contribute to the decline of steroidogenesis, decreased fertilization rate, oocyte maturation rate, and oocyte quality, and it can ultimately jeopardize fertility.

scholarly journals Mouse Sperm Membrane Potential Hyperpolarization Is Necessary and Sufficient to Prepare Sperm for the Acrosome Reaction

2012 ◽  
Vol 287 (53) ◽  
pp. 44384-44393 ◽  
Author(s):  
Jose Luis De La Vega-Beltran ◽  
Claudia Sánchez-Cárdenas ◽  
Darío Krapf ◽  
Enrique O. Hernandez-González ◽  
Eva Wertheimer ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Acrosome Reaction ◽  
Mouse Sperm ◽  
Sperm Membrane ◽  
Necessary And Sufficient

scholarly journals Determination of a Robust Assay for Human Sperm Membrane Potential Analysis

2019 ◽  
Vol 7 ◽  
Author(s):  
Carolina Baro Graf ◽  
Carla Ritagliati ◽  
Cintia Stival ◽  
Paula A. Balestrini ◽  
Mariano G. Buffone ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Human Sperm ◽  
Potential Analysis ◽  
Sperm Membrane

scholarly journals Mouse sperm membrane potential: changes induced by Ca2+

FEBS Letters ◽  
1995 ◽  
Vol 372 (1) ◽  
pp. 119-125 ◽  
Author(s):  
Felipe Espinosa ◽  
Alberto Darszon
Keyword(s):  
Membrane Potential ◽  
Mouse Sperm ◽  
Sperm Membrane

Measurement of spontaneous neuronal membrane activity by time lapse confocal microscopy

1995 ◽  
Vol 53 ◽  
pp. 972-973
Author(s):  
R H. Selinfreund ◽  
A. H. Cornell-Bell
Keyword(s):  
Membrane Potential ◽  
Confocal Microscopy ◽  
Patch Clamp ◽  
Electrical Activity ◽  
Time Lapse ◽  
Neuronal Firing ◽  
Neuronal Membrane ◽  
Pituitary Cells ◽  
Patch Clamp Recording ◽  
Spontaneous Electrical Activity

Cellular electrophysiological properties are normally monitored by standard patch clamp techniques . The combination of membrane potential dyes with time-lapse laser confocal microscopy provides a more direct, least destructive rapid method for monitoring changes in neuronal electrical activity. Using membrane potential dyes we found that spontaneous action potential firing can be detected using time-lapse confocal microscopy. Initially, patch clamp recording techniques were used to verify spontaneous electrical activity in GH4\C1 pituitary cells. It was found that serum depleted cells had reduced spontaneous electrical activity. Brief exposure to the serum derived growth factor, IGF-1, reconstituted electrical activity. We have examined the possibility of developing a rapid fluorescent assay to measure neuronal activity using membrane potential dyes. This neuronal regeneration assay has been adapted to run on a confocal microscope. Quantitative fluorescence is then used to measure a compounds ability to regenerate neuronal firing.The membrane potential dye di-8-ANEPPS was selected for these experiments. Di-8- ANEPPS is internalized slowly, has a high signal to noise ratio (40:1), has a linear fluorescent response to change in voltage.

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