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001-es BibID:	BIBFORM043635
Első szerző:	Izumi, Hiroko
Cím:	Membrane Hyperpolarization by Sperm-Activating and -Attracting Factor Increases cAMP Level and Activates Sperm Motility in the Ascidian Ciona intestinalis / Hiroko Izumi, Teréz Márián, Kazuo Inaba, Yoshitaka Oka, Masaaki Morisawa
Dátum:	1999
ISSN:	0012-1606
Megjegyzések:	In the ascidian Ciona intestinalis (and C. savignyi), sperm-activating and -attracting factor (SAAF) is released from the egg at fertilization and stimulates both Ca(2+) influx and a transient increase in cAMP level of the sperm, leading to the activation of sperm motility (M. Yoshida et al., 1994, Dev. Growth Differ. 36, 589-595). In this paper we show in C. intestinalis that valinomycin, a potassium-selective ionophore, as well as SAAF, activated sperm motility, and this activation was suppressed by extracellular high K(+). Membrane potential measurements showed that both SAAF and valinomycin increase K(+) permeability of sperm and induce membrane hyperpolarization, the amplitude of which depends on the external K(+) concentration. The membrane potential and intracellular K(+) concentration of Ciona sperm without SAAF were estimated to be about -50 mV and 560 +/- 40 mM, respectively. After treatment with SAAF or valinomycin the membrane potential became almost equal to the equilibrium potential of K(+) (-100 mV), and the cAMP level increased in artificial seawater. A potent voltage-dependent K(+) channel blocker, MCD peptide, at the concentration of 10 microM blocked SAAF-induced hyperpolarization of the cells, increase in cAMP, and sperm motility. These results suggest that membrane hyperpolarization produced by the opening of K(+) channels elevates cAMP synthesis and leads to the activation of sperm motility in Ciona.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Developmental Biology. - 213 : 2 (1999), p. 246-256. -
További szerzők:	Márián Teréz (1950-) (radiobiológus) Inaba, Kazuo Oka, Yoshitaka Morisawa, Masaaki
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001-es BibID:	BIBFORM004730
Első szerző:	Krasznai Zoltán (biofizikus)
Cím:	Gadolinium, a mechano-sensitive channel blocker, inhibits osmosis-initiated motility of sea- and freshwater fish sperm, but does not affect human or ascidian sperm motility / Krasznai, Z., Morisawa, M., Krasznai, Z. T., Morisawa, S., Inaba, K., Bazsane Kassai Z., Rubovszky, B., Bodnar, B., Borsos, A., Marian, T.
Dátum:	2003
ISSN:	886-1544 (Print)
Megjegyzések:	Exposure to hypo-osmotic or hyperosmotic environment triggers the initiation of fish sperm motility. In this article, we report that calcium and potassium channel blockers do not influence motility of puffer fish sperm but calmodulin antagonists reversibly decrease it, suggesting that calmodulin-Ca(2+) interactions are prerequisite for the initiation of sperm motility in this species. Gadolinium (a stretch activated ion channel blocker) decreased the motility of puffer fish sperm from 92 +/- 3% to 6 +/- 3% and that of carp sperm from 91 +/- 7% to 3.5 +/- 4.3% in a dose-dependent manner (10-40 micro M). The effect of gadolinium was reversible, suggesting that stretch activated ion channels participate in the initiation of sperm motility of the two species. Gadolinium inhibits changes in the isoelectric point of certain proteins of puffer fish sperm, which occur when sperm motility is initiated in a hypertonic solution. Anisotropy measurements showed that hypo-osmotic treatment, which initiates carp sperm motility, increased membrane fluidity. When hypo-osmotic treatment was given in the presence of gadolinium, the sperm membrane remained as rigid as in quiescent cells, while motility was blocked. By contrast, gadolinium did not influence the motility parameters of Ciona or human sperm. Based on these lines of evidence, we suggest that conformational changes of mechanosensitive membrane proteins are involved in osmolality-dependent but not osmolality-independent sperm
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Animals Biophysics Calcium Carps Cells Ciona intestinalis Dose-Response Relationship,Drug drug effects Gadolinium Human Humans Hungary Ion Channel Gating Ion Channels Male Membrane Fluidity Membrane Proteins metabolism Osmotic Pressure pharmacology physiology Potassium Potassium Channel Blockers Proteins Research Sperm Motility Support Takifugu
Megjelenés:	Cell Motility and the Cytoskeleton. - 55 : 4 (2003), p. 232-243. -
További szerzők:	Morisawa, Masaaki Krasznai Zoárd Tibor (1973-) (szülész-nőgyógyász, gyermeknőgyógyász) Morisawa, Sachiko Inaba, Kazuo Bazsáné Kassai Zsuzsa (1946-) (embriológus) Rubovszky Bálint (1975-) (élettanász) Bodnár B. Borsos Antal (1939-) (szülész-nőgyógyász, gyermeknőgyógyász) Márián Teréz (1950-) (radiobiológus)
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