Control of hyperactivation in sperm
TLDR
Computer-assisted semen analysis systems can be used to identify hyperactivated sperm by setting minimum thresholds for curvilinear velocity and lateral head movement and a maximum threshold for path linearity, which could enable clinicians to develop reliable fertility assays to assess normal hyperactivation in human sperm samples.Abstract:
BACKGROUND: Sperm hyperactivation is critical to fertilization, because it is required for penetration of the zona pellucida. Hyperactivation may also facilitate release of sperm from the oviductal storage reservoir and may propel sperm through mucus in the oviductal lumen and the matrix of the cumulus oophorus. Hyperactivation is characterized by high amplitude, asymmetrical flagellar bending. METHODS: This is a review of the original literature on the mechanisms that regulate hyperactivation, including physiological factors and signaling pathways. RESULTS: Computer-assisted semen analysis systems can be used to identify hyperactivated sperm by setting minimum thresholds for curvilinear velocity (VSL) and lateral head movement and a maximum threshold for path linearity. Hyperactivation is triggered by a rise in flagellar Ca(2+) resulting from influx primarily through plasma membrane CatSper channels and possibly also by release of Ca(2+) from a store in the redundant nuclear envelope. It requires increased pH and ATP production. The physiological signals that trigger the rise in Ca(2+) remain elusive, but there is evidence that the increased Ca(2+) acts through a calmodulin/calmodulin kinase pathway. Hyperactivation is considered part of the capacitation process; however, the regulatory pathway that triggers hyperactivation can operate independently from that which prepares sperm to undergo the acrosome reaction. Hyperactivation may be modulated by chemotactic signals to turn sperm toward the oocyte. CONCLUSIONS: Little is known about exactly what triggers hyperactivation in human sperm. This information could enable clinicians to develop reliable fertility assays to assess normal hyperactivation in human sperm samples.read more
Citations
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Journal ArticleDOI
Effect of oxidative stress on male reproduction.
TL;DR: This review highlights the mechanisms of ROS production, the physiological and pathophysiological roles of ROS in relation to the male reproductive system, and recent advances in diagnostic methods; it also explores the benefits of using antioxidants in a clinical setting.
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The CatSper channel mediates progesterone-induced Ca2+ influx in human sperm
Timo Strünker,Normann Goodwin,Christoph Brenker,Nachiket D. Kashikar,Nachiket D. Kashikar,Ingo Weyand,Reinhard Seifert,U. Benjamin Kaupp +7 more
TL;DR: It is found that both progesterone and alkaline pH stimulate a rapid Ca2+ influx with almost no latency, incompatible with a signalling pathway involving metabotropic receptors and second messengers.
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Acid Extrusion from Human Spermatozoa Is Mediated by Flagellar Voltage-Gated Proton Channel
TL;DR: By successfully patch clamping human spermatozoa, it is shown that proton channel Hv1 is their dominant proton conductance, which makes it an attractive target for controlling male fertility.
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Mammalian Sperm Motility: Observation and Theory
Eamonn A. Gaffney,Hermes Gadêlha,Hermes Gadêlha,David J. Smith,David J. Smith,John Blake,Jackson Kirkman-Brown +6 more
TL;DR: The biological structure of the motile sperm appendage, the flagellum, is described and placed in the context of the mechanics underlying the migration of mammalian sperm through the numerous environments of the female reproductive tract.
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The control of male fertility by spermatozoan ion channels.
TL;DR: How ion channels regulate sperm physiology is discussed, including mutations and deletions in sperm-specific ion channels affect male fertility in both mice and humans without affecting other physiological functions.
References
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Book
The Physiology of Reproduction
Ernst Knobil,J. D. Neill +1 more
TL;DR: The gametes, fertilization and early embryogenesis the reproductive systems - the female, the male the pituitary and the hypothalmus, and the reproductive processes and their control.
Journal ArticleDOI
Sperm transport in the female reproductive tract
Susan S. Suarez,Allan A. Pacey +1 more
TL;DR: Knowledge of the biology of sperm transport can inspire improvements in artificial insemination, IVF, the diagnosis of infertility and the development of contraceptives.
Journal ArticleDOI
Congenital Deafness and Sinoatrial Node Dysfunction in Mice Lacking Class D L-Type Ca2+ Channels
Josef Platzer,Jutta Engel,Anneliese Schrott-Fischer,K Stephan,Sergio Bova,Howard Y. Chen,Hui Zheng,Jörg Striessnig +7 more
TL;DR: It is concluded that alpha1D can form LTCCs with negative activation thresholds essential for normal auditory function and control of cardiac pacemaker activity.
Journal ArticleDOI
A sperm ion channel required for sperm motility and male fertility
Dejian Ren,Betsy Navarro,Gloria I. Perez,Alexander C. Jackson,Shyue-Fang Hsu,Qing Shi,Jonathan L. Tilly,David E. Clapham +7 more
TL;DR: A putative sperm cation channel, CatSper, whose amino-acid sequence most closely resembles a single, six-transmembrane-spanning repeat of the voltage-dependent Ca2+-channel four-repeat structure is described, located specifically in the principal piece of the sperm tail.
Journal ArticleDOI
Soluble Adenylyl Cyclase as an Evolutionarily Conserved Bicarbonate Sensor
Yanqiu Chen,Martin J. Cann,Tatiana N. Litvin,Vadim Iourgenko,Meeghan L. Sinclair,Lonny R. Levin,Jochen Buck +6 more
TL;DR: It is demonstrated here that bicarbonate directly stimulates mammalian soluble adenylyl cyclase (sAC) activity in vivo and in vitro in a pH-independent manner, which suggests that bICarbonate regulation of cAMP signaling plays a fundamental role in many biological systems.