Regulation of calcium transport in bovine spermatozoa

Breitbart, Haim; Wehbie, Robert S.; Lardy, Henry A.

doi:10.1016/0005-2736(90)90050-x

Cited by 25 publications

(10 citation statements)

References 21 publications

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“…The source of the Ca'-is unlikely to have originated from Ca2+ released from any cells dying during the course of the measurements, as extracellular Ca'-levels did not change during this time. The data support the suggestions that the mitochondria (Berruti and Franchi 1986;Vijayaraghavan and Hoskins 1989;Breitbart et al 1990) could serve as an internal Cat* pool of both free and citrate-chelated Ca2+. Spermatozoi lack the traditional Ca2+ depot, the endoplasmic reticulum (Eddy 1988 (Buhr et al 1989;de Leeuw et al 1991 (Rufo et al 1984).…”

Section: Microscopysupporting

confidence: 86%

Cryopreservation alters the Ca²⁺ flux of bovine spermatozoa

Bailey¹,

Buhr²

1994

Can. J. Anim. Sci.

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. 1994. Cryopreservation alters the Ca2* flux of bovine spermatozoa. Can. J. Anim. Sci. 74: 45-51. Capacitation and the acrosome reaction are Ca2*-dependent events that must be properly timed for successful fertilization to occur. To test the hypothesis that the cryopreservation procedures alter the ability ofbovine spermatozoa to regulate Ca'-, the ability of Percoll-washed fresh and cryopreserved spermatozoa obtained from the same ejaculate (four ejaculates from each of six bulls) to regulate Ca" over time was monitored using the fluorescent Ca'' chelator indo-1. The ability of spermatozoa to control Ca'* levels varied among ejaculates from a bull, and among bulls; these effects were statistically accounted for in the analysis of the effects of cryopreservation. Initially, cryopreserved spermatozoa had lower viability, motility, and normal acrosome scores and more intra-and extra-cellular Ca'-than fresh spermatozoa. Intra-and extra-cellular Ca'-was monitored for,150 min, with I mM exogenous Ca2* or buffer being added at 30 min to the spermatozoa being used to monitor intracellular Ca2*. By 30 min, extracelirilar Ca2* was higher for fiesh cells and then remained constant. Intracellular Ca2* of fresh and cryopresewed spermatozoa in Ca2*-free media"slowly increased. While both fresh and cryopreserved cells in Ca2*-supplemented media accumulated Ca2* more rapidly, cryopreserved spermatozoa did so faster than fresh. Post-experimental viability was lower in cryopreserved spermatozoa that had been exposed to exogenous Ca'*. In conclusion, cryopreservation affects initial intraand extia-cellular Ca2* levels of bovine spermitozoa, and iheir ability to control subsequent rates of Ca2* accumulation.

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Section: Microscopysupporting

confidence: 86%

Cryopreservation alters the Ca²⁺ flux of bovine spermatozoa

Bailey¹,

Buhr²

1994

Can. J. Anim. Sci.

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“…The use of Ca 2ϩ by the cell as an intracellular messenger requires precise regulation of its intracellular concentration [1]. Proposed regulatory sites of sperm intracellular calcium include both the plasma membrane [2] and the mitochondria [3][4][5]. The fact that sperm intracellular Ca 2ϩ is maintained at a very low level (Ͻ 0.1 M) in a medium containing millimolar Ca 2ϩ supports the concept that the plasma membrane is the primary regulatory site.…”

Section: Introductionmentioning

confidence: 89%

Intracellular Ca2+-Mg2+-ATPase Regulates Calcium Influx and Acrosomal Exocytosis in Bull and Ram Spermatozoa1

Dragileva

Rubinstein

Breitbart

1999

Biology of Reproduction

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Calcium influx is required for the mammalian sperm acrosome reaction (AR), an exocytotic event occurring in the sperm head prior to fertilization. We show here that thapsigargin, a highly specific inhibitor of the microsomal Ca(2+)-Mg(2+)-ATPase (Ca(2+) pump), can initiate acrosomal exocytosis in capacitated bovine and ram spermatozoa. Initiation of acrosomal exocytosis by thapsigargin requires an influx of Ca(2+), since incubation of cells in the absence of added Ca(2+) or in the presence of the calcium channel blocker, La(3+), completely inhibited thapsigargin-induced acrosomal exocytosis. ATP-Dependent calcium accumulation into nonmitochondrial stores was detected in permeabilized sperm in the presence of ATP and mitochondrial uncoupler. This activity was inhibited by thapsigargin. Thapsigargin elevated the intracellular Ca(2+) concentration ([Ca(2+)](i)), and this increase was inhibited when extracellular Ca(2+) was chelated by EGTA, indicating that this rise in Ca(2+) is derived from the external medium. This rise of [Ca(2+)](i) took place first in the head and later in the midpiece of the spermatozoon. However, immunostaining using a polyclonal antibody directed against the purified inositol 1,4,5-tris-phosphate receptor (IP(3)-R) identified specific staining in the acrosome region, in the postacrosome, and along the tail, but not in the midpiece region. No staining in the acrosome region was observed in sperm without acrosome, indicating that the acrosome cap was stained in intact sperm. The presence of IP(3)-R in the anterior acrosomal region as well as the induction, by thapsigargin, of intracellular Ca(2+) elevation in the acrosomal region and acrosomal exocytosis, implicates the acrosome as a potential cellular Ca(2+) store. We suggest here that the cytosolic Ca(2+) is actively transported into the acrosome by an ATP-dependent, thapsigargin-sensitive Ca(2+) pump and that the accumulated Ca(2+) is released from the acrosome via an IP(3)-gated calcium channel. The ability of thapsigargin to increase [Ca(2+)](i) could be due to depletion of Ca(2+) in the acrosome, resulting in the opening of a capacitative calcium entry channel in the plasma membrane. The effect of thapsigargin on elevated [Ca(2+)](i) in capacitated cells was 2-fold higher than that in noncapacitated sperm, suggesting that the intracellular Ca pump is active during capacitation and that this pump may have a role in regulating [Ca(2+)](i) during capacitation and the AR.

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“…Induction of caudal spermatozoa motility is likely dependent on a transient increase in cytosolic Ca 2C followed by a secondary increase in cyclic AMP. The rate of calcium transport into the sperm relies on the ability of mitochondrial Ca 2C uptake to maintain an adequate gradient for plasmalemma Ca 2C influx, whereas the rate of such transport is dependent in turn on the rate of aerobic respiration fueled by various substrates (Hoskins et al 1978, Breitbart et al 1990. Although ERp29 cannot bind calcium, it may have interactions with calciumbinding molecular chaperones on the membrane of mitochondrial sheath, e.g.…”

Section: Identification Of Erp29 In Epididymismentioning

confidence: 99%

Identification and characterization of ERp29 in rat spermatozoa during epididymal transit

Guo¹,

Qü²,

Li³

et al. 2007

Reproduction

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The mammalian epididymis is able to create sequential changes in the composition of luminal fluid throughout its length, wherein spermatozoa undergo morphological, biochemical, and physiological modifications. Subsequently, spermatozoa acquire the ability for fertilization upon reaching the epididymal cauda. In this study, protein variations in Sprague-Dawley rat spermatozoa along the caput and caudal regions of epididymis were investigated by high-resolution two-dimensional gel electrophoresis (2DE) in combination with mass spectrometry. From total protein spots on the 2DE maps, 43 spots were shown to be significantly modified as sperm traverse the epididymis, and seven unambiguous proteins were identified from them. Finally, using indirect immunofluorescence, we demonstrated that localization of one of these seven proteins, the endoplasmic reticulum protein (ERp29) precursor, which was first reported in mammalian spermatozoa, was apparently up-regulated as the sperm underwent epididymal maturation and expressed mainly on caudal sperm. Western blot analysis also revealed that ERp29 precursor, from both whole spermatozoa and membrane proteins, increased significantly as the sperm underwent epididymal maturation. Furthermore, the results from immunofluorescence-stained epididymal frozen sections demonstrated that ERp29 was localized in cytoplasm of epididymal epithelia, and the fluorescence intensity was significantly higher in the caudal epididymis than in the caput. These clues indicated that the ERp29 precursor, perhaps related to secretory protein synthesis and absorbed by spermatozoa, may play a vital role in sperm maturation during the epididymal transit, particularly, in the sperm/organelle membrane. Reproduction (2007) 133 575-584

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Regulation of calcium transport in bovine spermatozoa

Cited by 25 publications

References 21 publications

Cryopreservation alters the Ca²⁺ flux of bovine spermatozoa

Cryopreservation alters the Ca²⁺ flux of bovine spermatozoa

Intracellular Ca2+-Mg2+-ATPase Regulates Calcium Influx and Acrosomal Exocytosis in Bull and Ram Spermatozoa1

Identification and characterization of ERp29 in rat spermatozoa during epididymal transit

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Regulation of calcium transport in bovine spermatozoa

Cited by 25 publications

References 21 publications

Cryopreservation alters the Ca2+ flux of bovine spermatozoa

Cryopreservation alters the Ca2+ flux of bovine spermatozoa

Intracellular Ca2+-Mg2+-ATPase Regulates Calcium Influx and Acrosomal Exocytosis in Bull and Ram Spermatozoa1

Identification and characterization of ERp29 in rat spermatozoa during epididymal transit

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Cryopreservation alters the Ca²⁺ flux of bovine spermatozoa

Cryopreservation alters the Ca²⁺ flux of bovine spermatozoa