scholarly journals Elucidating the Role of K+ Channels during In Vitro Capacitation of Boar Spermatozoa: Do SLO1 Channels Play a Crucial Role?

2019 ◽  
Vol 20 (24) ◽  
pp. 6330 ◽  
Author(s):  
Marc Yeste ◽  
Marc Llavanera ◽  
Guillermo Pérez ◽  
Fabiana Scornik ◽  
Josep Puig-Parri ◽  
...  
Keyword(s):  
Sperm Motility ◽  
Channel Blocker ◽  
Physiological Role ◽  
Membrane Lipid ◽  
K Channel ◽  
Sperm Capacitation ◽  
Lipid Disorder ◽  
Principal Piece ◽  
Boar Spermatozoa

This study sought to identify and localize SLO1 channels in boar spermatozoa by immunoblotting and immunofluorescence, and to determine their physiological role during in vitro sperm capacitation. Sperm samples from 14 boars were incubated in a capacitation medium for 300 min in the presence of paxilline (PAX), a specific SLO1-channel blocker, added either at 0 min or after 240 min of incubation. Negative controls were incubated in capacitation medium, and positive controls in capacitation medium plus tetraethyl ammonium (TEA), a general K+-channel blocker, also added at 0 min or after 240 min of incubation. In all samples, acrosome exocytosis was triggered with progesterone after 240 min of incubation. Sperm motility and kinematics, integrity of plasma and acrosome membranes, membrane lipid disorder, intracellular calcium levels and acrosin activity were evaluated after 0, 60, 120, 180, 240, 250, 270 and 300 min of incubation. In boar spermatozoa, SLO1 channels were found to have 80 kDa and be localized in the anterior postacrosomal region and the mid and principal piece of the tail; their specific blockage through PAX resulted in altered calcium levels and acrosome exocytosis. As expected, TEA blocker impaired in vitro sperm capacitation, by altering sperm motility and kinematics and calcium levels. In conclusion, SLO1 channels are crucial for the acrosome exocytosis induced by progesterone in in vitro capacitated boar spermatozoa.

scholarly journals HVCN1 Channels Are Relevant for the Maintenance of Sperm Motility During In Vitro Capacitation of Pig Spermatozoa

2020 ◽  
Vol 21 (9) ◽  
pp. 3255
Author(s):  
Marc Yeste ◽  
Marc Llavanera ◽  
Yentel Mateo-Otero ◽  
Jaime Catalán ◽  
Sergi Bonet ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Sperm Motility ◽  
Mitochondrial Membrane ◽  
Membrane Lipid ◽  
Sperm Head ◽  
Sperm Viability ◽  
Lipid Disorder ◽  
Acrosomal Exocytosis ◽  
Control Samples

The objective of the present study was to determine the physiological role of voltage-gated hydrogen channels 1 (HVCN1 channels) during in vitro capacitation of pig spermatozoa. Sperm samples from 20 boars were incubated in capacitating medium for 300 minutes (min) in the presence of 2-guanidino benzimidazole (2-GBI), a specific HVCN1-channel blocker, added either at 0 min or after 240 min of incubation. Control samples were incubated in capacitating medium without the inhibitor. In all samples, acrosomal exocytosis was triggered with progesterone after 240 min of incubation. Sperm viability, sperm motility and kinematics, acrosomal exocytosis, membrane lipid disorder, intracellular calcium levels and mitochondrial membrane potential were evaluated after 0, 60, 120, 180, 240, 250, 270 and 300 min of incubation. While HVCN1-blockage resulted in altered sperm viability, sperm motility and kinematics and reduced mitochondrial membrane potential as compared to control samples, at any blocker concentration and incubation time, it had a non-significant effect on intracellular Ca2+ levels determined through Fluo3-staining. The effects on acrosomal exocytosis were only significant in blocked samples at 0 min, and were associated with increased membrane lipid disorder and Ca2+ levels of the sperm head determined through Rhod5-staining. In conclusion, HVCN1 channels play a crucial role in the modulation of sperm motility and kinematics, and in Ca2+ entrance to the sperm head.

The capacitating agent bicarbonate induces protein kinase A-dependent changes in phospholipid transbilayer behavior in the sperm plasma membrane

Development ◽  
2000 ◽  
Vol 127 (11) ◽  
pp. 2407-2420 ◽  
Author(s):  
B.M. Gadella ◽  
R.A. Harrison
Keyword(s):  
Plasma Membrane ◽  
Membrane Lipid ◽  
Lipid Disorder ◽  
Outer Leaflet ◽  
Flow Cytometric ◽  
Merocyanine 540 ◽  
Sperm Plasma Membrane ◽  
Dependent Protein ◽  
Boar Spermatozoa

A flow cytometric procedure was used to follow the effect of bicarbonate, a key inducer of sperm capacitation in vitro, on the transbilayer behavior of C6NBD-phospholipids in the plasma membrane of living acrosome-intact boar spermatozoa under physiological conditions. In the absence of bicarbonate, 97% of C6NBD-phosphatidylserine and 78% of C6NBD-phosphatidylethanolamine was rapidly translocated from the outer leaflet to the inner, whereas relatively little C6NBD-phosphatidylcholine and C6NBD-sphingomyelin was translocated (15% and 5%, respectively). Inclusion of 15 mM bicarbonate/5%CO(2) markedly slowed down the rates of translocation of the aminophospholipids without altering their final distribution, whereas it increased the proportions of C6NBD-phosphatidylcholine and C6NBD-sphingomyelin translocated (30% and 20%, respectively). Bicarbonate activated very markedly the outward translocation of all four phospholipid classes. The changes in C6NBD-phospholipid behavior were accompanied by increased membrane lipid disorder as detected by merocyanine 540, and also by increased potential for phospholipase catabolism of the C6NBD-phospholipid probes. All three changes were mediated via a cAMP-dependent protein phosphorylation pathway. We suspect that the changes result from an activation of the non- specific bidirectional translocase ('scramblase'). They have important implications with respect to sperm fertilizing function.

scholarly journals Blocking NHE Channels Reduces the Ability of In Vitro Capacitated Mammalian Sperm to Respond to Progesterone Stimulus

2021 ◽  
Vol 22 (23) ◽  
pp. 12646
Author(s):  
Marc Yeste ◽  
Sandra Recuero ◽  
Carolina Maside ◽  
Albert Salas-Huetos ◽  
Sergi Bonet ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Mammalian Species ◽  
Physiological Role ◽  
Membrane Lipid ◽  
Equatorial Region ◽  
Lipid Disorder ◽  
Head Displacement ◽  
Mammalian Sperm ◽  
Few Data

Few data exist about the presence and physiological role of Na+/H+ exchangers (NHEs) in the plasma membrane of mammalian sperm. In addition, the involvement of these channels in the ability of sperm to undergo capacitation and acrosomal reaction has not been investigated in any mammalian species. In the present study, we addressed whether these channels are implicated in these two sperm events using the pig as a model. We also confirmed the presence of NHE1 channels in the plasma membrane of ejaculated sperm by immunofluorescence and immunoblotting. The function of NHE channels during in vitro capacitation was analyzed by incubating sperm samples in capacitating medium for 300 min in the absence or presence of a specific blocker (DMA; 5-(N,N-dimethyl)-amiloride) at different concentrations (1, 5, and 10 µM); acrosome exocytosis was triggered by adding progesterone after 240 min of incubation. Sperm motility and kinematics, integrity of plasma and acrosome membranes, membrane lipid disorder, intracellular calcium and reactive oxygen species (ROS) levels, and mitochondrial membrane potential (MMP) were evaluated after 0, 60, 120, 180, 240, 250, 270, and 300 min of incubation. NHE1 localized in the connecting and terminal pieces of the flagellum and in the equatorial region of the sperm head and was found to have a molecular weight of 75 kDa. During the first 240 min of incubation, i.e., before the addition of progesterone, blocked and control samples did not differ significantly in any of the parameters analyzed. However, from 250 min of incubation, samples treated with DMA showed significant alterations in total motility and the amplitude of lateral head displacement (ALH), acrosomal integrity, membrane lipid disorder, and MMP. In conclusion, while NHE channels are not involved in the sperm ability to undergo capacitation, they could be essential for triggering acrosome exocytosis and hypermotility after progesterone stimulus.

scholarly journals Cooling of equine semen at 16°C for 36 hours with addition of different glutathione concentrations

2015 ◽  
Vol 36 (6) ◽  
pp. 3699
Author(s):  
Rodrigo Arruda de Oliveira ◽  
Marco Antônio De Oliveira Viu ◽  
Maria Lúcia Gambarini
Keyword(s):  
Lipid Peroxidation ◽  
Sperm Motility ◽  
Membrane Integrity ◽  
Membrane Lipid ◽  
Sperm Cells ◽  
Sperm Viability ◽  
Membrane Lipid Peroxidation ◽  
Acrosomal Membrane ◽  
In Vitro Effects

Handling equine semen during the refrigeration process reduces sperm viability, and consequently causes membrane lipid peroxidation, among other challenges. The present study aimed to evaluate the in vitro effects of glutathione (control, 1. 0, 1. 5, and 2. 5 mM) on equine semen in a refrigeration protocol of 16ºC for 36 hours. The following variables were evaluated after 0, 12, 24, and 36 hours refrigeration: total sperm motility, vigor, viability, and plasma and acrosomal membrane integrity. Motility was higher with 2. 5mM of glutathione (57. 8 ± 7. 3) after 12 hours of refrigeration compared to the control (53. 2 ± 8. 3) (P < 0. 05). After 36 hours of refrigeration, motility was higher with 1. 5 mM (43. 4 ± 12. 7) and 2. 5mM glutathione (45. 5 ± 6. 2), than it was with 1mM glutathione (38. 2 ± 9) and the control (35. 5 ± 18. 4) (P < 0. 05), respectively. Vigor was highest with 1. 5mM glutathione (3. 7 ± 0. 3) after 36 hours compared to the control (3. 2 ± 1. 1), (P < 0. 05). Viability differed between control and 1mM treatments (79. 5 ± 1. 8) only after 24 hours (75. 5 ± 9. 7) (P < 0. 05). Throughout the investigation, no significant differences were noted in plasma and acrosomal membrane integrity (P > 0. 05). The 1. 5 and 2. 5mM glutathione levels were more efficient in protecting sperm cells and yielded higher total motility values after 36 hours of refrigeration.

Comparison of acetylcholine-dependent relaxation in large and small arteries of rat mesenteric vascular bed

1994 ◽  
Vol 266 (3) ◽  
pp. H952-H958 ◽  
Author(s):  
J. J. Hwa ◽  
L. Ghibaudi ◽  
P. Williams ◽  
M. Chatterjee
Keyword(s):  
Methylene Blue ◽  
Channel Blocker ◽  
Mesenteric Arteries ◽  
K Channel ◽  
Resistance Arteries ◽  
Vascular Bed ◽  
Mesenteric Vascular Bed ◽  
Relaxation Responses ◽  
Endothelium Dependent Relaxation

The relative contributions of nitric oxide (NO) to in vitro relaxation responses elicited by acetylcholine (ACh) were compared in vessels of different sizes from the rat mesenteric vascular bed. ACh elicited an endothelium-dependent relaxation in phenylephrine-contracted superior mesenteric arteries (SMA, unstretched luminal diam 650 microns), which was blocked by compounds that inhibited NO, such as hemoglobin (10 microM), methylene blue (10 microM), and NG-monomethyl-L-arginine (1 mM). In contrast, the endothelium-dependent relaxation induced by ACh in phenylephrine-contracted mesenteric resistance arteries (MRA, unstretched luminal diam 200 microns) was not blocked by hemoglobin, methylene blue, or NG-monomethyl-L-arginine. KCl (25 mM) partially inhibited the ACh-dependent relaxation in MRA. Furthermore, the ACh-dependent relaxation in MRA was selectively inhibited by the Ca(2+)-activated K+ channel blocker charybdotoxin (0.1 microM). In contrast, the ATP-sensitive K+ channel blocker glibenclamide (50 microM) did not block the ACh-dependent relaxation in MRA. We conclude that 1) NO is a major component of the ACh-dependent relaxation in SMA and 2) the ACh-dependent relaxation of MRA is resistant to NO inhibitors but sensitive to a Ca(2+)-activated K+ channel blocker. This suggests that an endothelium-derived hyperpolarization factor may be involved in the relaxation of MRA.

326 COMPARING CHANGES IN MEMBRANE LIPID ORDER IN EPIDIDYMAL AND EJACULATED BOAR SPERMATOZOA

2007 ◽  
Vol 19 (1) ◽  
pp. 277
Author(s):  
C. Matas ◽  
F. Garcia-Vazquez, ◽  
M. Sansegundo ◽  
S. Ruiz ◽  
J. Gadea
Keyword(s):  
Plasma Membrane ◽  
Seminal Plasma ◽  
Lipid Membrane ◽  
Calcium Influx ◽  
Membrane Lipid ◽  
Treatment Groups ◽  
Lipid Disorder ◽  
Lipid Order ◽  
Merocyanine 540 ◽  
Boar Spermatozoa

The diffusion of lipids in the plasma membrane of ejaculated spermatozoa is influenced by seminal plasma proteins and the composition of the suspending medium (Wolfe et al. 2001 Mol. Reprod. Dev. 59, 306–313). Merocyanine 540 (M540) is a hydrophobic dye that has been shown to stain cell membranes more intensely if their lipid components are in a higher state of disorder, as is the case of capacitated spermatozoa. It is believed that the membrane fluidity changes detected by M540 precede the calcium influx, making M540 a method for evaluating the early events of capacitation. The aim of this study was to determine if there are differences in the dynamics of lipid disorder in the plasma membrane of ejaculated and epididymal boar spermatozoa under different conditions of capacitation. The sperm capacitation treatments were: washed in Delbucco's PBS supplemented with 0.1 % BSA (PBS-BSA), washed on a Percoll gradient (PG), and unwashed (UW: Control). During measurement, the samples were kept at 38�C and 5 % CO2 to maintain constant incubation conditions. Membrane lipid order and sperm viability were determined by flow cytometry with M540 (2.7 �M) and Yo-Pro-1 (25 nM), respectively. Samples were analyzed on a Coulter Epics XL flow cytometer (Beckman Coulter Co., Inc., Fullerton, CA, USA). A total of 10 000 gated events were collected per sample, with sample running rates of approximately 600 events/s. Data were analyzed by analysis of variance (ANOVA). For the epidydimal vs. ejaculated results, the percentage of low lipid disorder spermatozoa was higher in the epididymal (19.23%) than in the ejaculated (5.84%) groups, and the proportion of high disorder (42.85%) and dead cells (48.59%) was higher in the ejaculated group. In relation to sperm treatment (UW, PBS-BSA, and PG), the percentage of high disorder was similar in all of the treatment groups (UW: 44.62 %; PBS-BSA: 43.08%; PG: 43.41%). Finally, the percentage of low disorder was lower in the PBS-BSA and PERCOLL (10.68% and 12.83%, respectively) groups, and the highest was obtained for the UW group (14.09%). In conclusion, the staining with M540 revealed that the lipid disorder was affected by the source of the sperm and the sperm treatment. A significant increase in membrane lipid low disorder and decrease in high disorder and dead cells were detected when epididymal sperm were compared with ejaculated sperm, so the seminal plasma and the sperm treatment to eliminate disorder have an important effect in the lipid membrane order. Supported by MEC (AGL2006-03495/GAN) and Fundaci�n S�neca (03018/PI/05).

Relaxant effect of xenin on rat ileum is mediated by apamin-sensitive neurotensin-type receptors

1997 ◽  
Vol 272 (1) ◽  
pp. G190-G196 ◽  
Author(s):  
A. Clemens ◽  
S. Katsoulis ◽  
R. Nustede ◽  
J. Seebeck ◽  
K. Seyfarth ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Channel Blocker ◽  
Muscle Cells ◽  
K Channel ◽  
Binding Studies ◽  
Relaxant Effect ◽  
Structure Activity ◽  
Neuromedin N

The action of xenin, a novel 25-residue peptide of the neurotensin (NT)/xenopsin family, was investigated in isolated rat ileal muscle strips and in dispersed longitudinal smooth muscle cells of rat small intestine in vitro. Xenin relaxes KCl-precontracted ileal strips dose dependently (1 nM-3 microM). The order of potency of the investigated peptides was as follows: xenopsin = NT = xenin > neuromedin N. Kinetensin was inactive. Tetrodotoxin, hexamethonium, tetraethylammonium, 4-aminopyridine, and NG-nitro-L-arginine did not influence the relaxant effects of xenin or NT, whereas the K+ channel blocker apamin nearly abolished their effects. Desensitization against one of the peptides or blockade of NT receptors by SR-48692 prevented the effect of xenin and NT. Structure-activity experiments revealed that the COOH-terminal part of the molecules of xenin and NT is essential for biological activity. Experiments with isolated dispersed smooth muscle cells and binding studies on intestinal smooth muscle cell membranes confirmed and extended the results obtained with muscle strips. In conclusion, xenin relaxes rat ileal smooth muscle via a muscular NT-type apamin-sensitive receptor.

scholarly journals HVCN1 but Not Potassium Channels Are Related to Mammalian Sperm Cryotolerance

2021 ◽  
Vol 22 (4) ◽  
pp. 1646
Author(s):  
Ariadna Delgado-Bermúdez ◽  
Yentel Mateo-Otero ◽  
Marc Llavanera ◽  
Sergi Bonet ◽  
Marc Yeste ◽  
...  
Keyword(s):  
Potassium Channels ◽  
Sperm Quality ◽  
Membrane Integrity ◽  
Physiological Role ◽  
Membrane Lipid ◽  
Proton Channels ◽  
Lipid Disorder ◽  
Mammalian Sperm

Little data exist about the physiological role of ion channels during the freeze–thaw process in mammalian sperm. Herein, we determined the relevance of potassium channels, including SLO1, and of voltage-gated proton channels (HVCN1) during mammalian sperm cryopreservation, using the pig as a model and through the addition of specific blockers (TEA: tetraethyl ammonium chloride, PAX: paxilline or 2-GBI: 2-guanidino benzimidazole) to the cryoprotective media at either 15 °C or 5 °C. Sperm quality of the control and blocked samples was performed at 30- and 240-min post-thaw, by assessing sperm motility and kinematics, plasma and acrosome membrane integrity, membrane lipid disorder, intracellular calcium levels, mitochondrial membrane potential, and intracellular O2−⁻ and H2O2 levels. General blockade of K+ channels by TEA and specific blockade of SLO1 channels by PAX did not result in alterations in sperm quality after thawing as compared to control samples. In contrast, HVCN1-blocking with 2-GBI led to a significant decrease in post-thaw sperm quality as compared to the control, despite intracellular O2−⁻ and H2O2 levels in 2-GBI blocked samples being lower than in the control and in TEA- and PAX-blocked samples. We can thus conclude that HVCN1 channels are related to mammalian sperm cryotolerance and have an essential role during cryopreservation. In contrast, potassium channels do not seem to play such an instrumental role.

scholarly journals Parkinson Disease Protein 7 (PARK7) Is Related to the Ability of Mammalian Sperm to Undergo In Vitro Capacitation

2021 ◽  
Vol 22 (19) ◽  
pp. 10804
Author(s):  
Sandra Recuero ◽  
Ariadna Delgado-Bermúdez ◽  
Yentel Mateo-Otero ◽  
Estela Garcia-Bonavila ◽  
Marc Llavanera ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Parkinson Disease ◽  
Intracellular Calcium ◽  
Sperm Motility ◽  
Antioxidant Properties ◽  
Lipid Disorder ◽  
Mammalian Sperm ◽  
Acrosomal Exocytosis ◽  
Disease Protein

Parkinson disease protein 7 (PARK7) is a multifunctional protein known to be involved in the regulation of sperm motility, mitochondrial function, and oxidative stress response in mammalian sperm. While ROS generation is needed to activate the downstream signaling pathways required for sperm to undergo capacitation, oxidative stress has detrimental effects for sperm cells and a precise balance between ROS levels and antioxidant activity is needed. Considering the putative antioxidant role of PARK7, the present work sought to determine whether this protein is related to the sperm ability to withstand in vitro capacitation. To this end, and using the pig as a model, semen samples were incubated in capacitation medium for 300 min; the acrosomal exocytosis was triggered by the addition of progesterone after 240 min of incubation. At each relevant time point (0, 120, 240, 250, and 300 min), sperm motility, acrosome and plasma membrane integrity, membrane lipid disorder, mitochondrial membrane potential, intracellular calcium and ROS were evaluated. In addition, localization and protein levels of PARK7 were also assessed through immunofluorescence and immunoblotting. Based on the relative content of PARK7, two groups of samples were set. As early as 120 min of incubation, sperm samples with larger PARK7 content showed higher percentages of viable and acrosome-intact sperm, lipid disorder and superoxide levels, and lower intracellular calcium levels when compared to sperm samples with lower PARK7. These data suggest that PARK7 could play a role in preventing sperm from undergoing premature capacitation, maintaining sperm viability and providing a better ability to keep ROS homeostasis, which is needed to elicit sperm capacitation. Further studies are required to elucidate the antioxidant properties of PARK7 during in vitro capacitation and acrosomal exocytosis of mammalian sperm, and the relationship between PARK7 and sperm motility.

18 EFFECTS OF SKIM MILK ON THE QUALITY AND FERTILITY OF BOAR SEMEN FOLLOWING LIQUID PRESERVATION AT 5°C AND 15°C

2011 ◽  
Vol 23 (1) ◽  
pp. 115 ◽  
Author(s):  
Z. Namula ◽  
R. Kodama ◽  
Y. Kaedei ◽  
F. Tanihara ◽  
V. L. Vien ◽  
...  
Keyword(s):  
Sperm Motility ◽  
Storage Temperature ◽  
Semen Quality ◽  
Sperm Concentration ◽  
Membrane Integrity ◽  
Skim Milk ◽  
Control Group ◽  
Boar Semen ◽  
Boar Spermatozoa

Liquid preservation of semen can be an alternative to frozen–thawed semen for artificial insemination. The success of a selection of boar semen extenders has been studied over storage periods of 5 to 7 days. The objective of this study was to evaluate the effects of skim milk on the viability and in vitro fertility of boar spermatozoa preserved in Modena-based extenders at 5°C and 15°C for 2 weeks. A total of 7 ejaculates were collected from one boar. The sperm-rich fraction of each ejaculate was centrifuged and diluted in Modena extenders supplemented with 0 (control), 7.5, and 15 mg mL–1 of dry skim milk. The final sperm concentration was adjusted to 1 × 108 cells mL–1, and then the semen was stored at 5°C and 15°C for 2 weeks. In the first experiment, the motility, viability (live/dead fluorescence viability assay), plasma membrane integrity (hypoosmotic swelling test; HOST), and acrosome integrity (FITC-labelled peanut agglutinin staining) of semen stored for 2 weeks were assessed. In the second experiment, the fertilization of stored semen after 20 h of co-incubation with in vitro matured oocytes and their development were examined. Data were analysed using ANOVA. When the semen was stored at 5°C for 2 weeks, the mean total sperm motility of semen stored with 7.5 and 15 mg mL–1 of dry skim milk was significantly higher than that of semen in the control group (41.4% and 41.5% v. 17.4%; P < 0.05). However, the beneficial effects of skim milk on the sperm motility were not observed in the semen stored at 15°C. Moreover, there were no significant differences in the other parameters of semen quality among the groups in each storage temperature. Significantly higher penetration rates of semen stored with 7.5 and 15 mg mL–1 of dry skim milk were observed in the storage at 5°C (41.1% and 34.8% v. 19.8%; P < 0.05) but not at 15°C (38.9% and 26.0% v. 30.0%; P > 0.05) when compared with the control group. When the semen was stored at 5°C, the development rate to the blastocyst stage of oocytes fertilized with semen stored with 7.5 mg mL–1 of dry skim milk was significantly higher than that with control and 15 mg mL–1 of dry skim milk (15.4% v. 1.1% and 7.8%; P < 0.01). However, there were no significant differences in the development rates of oocytes fertilized with semen stored at 15°C among the groups (9.6–11.9%). In conclusion, our results indicate that the effect of skim milk on the viability and in vitro fertility of liquid-stored boar spermatozoa is dependent on the storage temperature. The addition of 7.5 mg mL–1 of dry skim milk may be effective for the improvement of viability and fertility of semen stored at 5°C but not at 15°C.

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