title: Regulation of fowl sperm motility: evidence for the indirect, but not direct, involvement of dynein-ATPase activity on the reversible temperature-dependent immobilization.
abstract: Potential mechanisms of the reversible temperature-dependent immobilization of fowl sperm were investigated. At 30 °C, motility of demembranated fowl sperm was inhibited by adding 2 mM ethylene glycol-bis (2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), but restored immediately after the subsequent addition of 2 mM CaCl(2), whereas at 40 °C, such additions did not appreciably affect motility (which remained almost negligible). With intact sperm, 10(-9) to 10(-3) M Ca(2+) had no effect on motility at 30 °C, which remained high. In contrast, intact sperm at 40 °C were almost immotile below 10(-5) M Ca(2+), and then gradually recovered motility at higher Ca(2+) concentrations. The negligible motility of demembranated sperm at 40 °C, and at 30 °C in the presence of EGTA, was stimulated by addition of 100 nM of the protein phosphatase inhibitor calyculin A. Dynein-ATPase activities of sperm at 40 °C in the presence of 2 mM EGTA, 2 μM CaCl(2), 2 mM CaCl(2,) or 100 nM calyculin A were higher than those at 30 °C. Therefore, stimulation of fowl sperm motility by temperature, Ca(2+), and phosphatase inhibition was not simply associated with an increase of flagellar dynein-ATPase activity. Furthermore, Ca(2+) was essential, at the axonemal level, for initiation of the 'intrinsic' motility of fowl sperm at 30 °C, but this Ca(2+)-dependent mechanism might be different from that involved in restoration of motility of intact sperm at 40 °C. In addition, perhaps inhibition of protein phosphatase activity was involved in initiation of sperm motility, but acting at a location different from Ca(2+) on the axoneme.
authors.affiliation: Laboratory of Animal Reproduction, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan. ashizawa@cc.miyazaki-u.ac.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Ashizawa
authors.forename: Nao
authors.initials: N
authors.lastname: Oyama
authors.forename: Seiichi
authors.initials: S
authors.lastname: Katayama
authors.forename: Kazunori
authors.initials: K
authors.lastname: Narumi
authors.forename: Hideki
authors.initials: H
authors.lastname: Tatemoto
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tsuzuki
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002462:Cell Membrane / Q000502:physiology; D002645:Chickens / Q000502:physiology*; D004398:Dyneins / Q000037:antagonists & inhibitors / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D008387:Marine Toxins; D008560:Membrane Fluidity / Q000187:drug effects; D010080:Oxazoles / Q000494:pharmacology; D054645:Protein Phosphatase 1 / Q000037:antagonists & inhibitors / Q000502:physiology; D054648:Protein Phosphatase 2 / Q000037:antagonists & inhibitors / Q000502:physiology; D013081:Sperm Motility / Q000187:drug effects / Q000502:physiology*; D013094:Spermatozoa / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D013696:Temperature
chemical_list: D004791:Enzyme Inhibitors; D008387:Marine Toxins; D010080:Oxazoles; C059041:calyculin A; D054645:Protein Phosphatase 1; D054648:Protein Phosphatase 2; D004398:Dyneins; D002118:Calcium