Sperm motility enhancement by nitric oxide produced by the oocytes of fathead minnows, Pimephelas promelas

Citation
Mm. Creech et al., Sperm motility enhancement by nitric oxide produced by the oocytes of fathead minnows, Pimephelas promelas, J ANDROLOGY, 19(6), 1998, pp. 667-674
Citations number
37
Categorie Soggetti
da verificare
Journal title
JOURNAL OF ANDROLOGY
ISSN journal
01963635 → ACNP
Volume
19
Issue
6
Year of publication
1998
Pages
667 - 674
Database
ISI
SICI code
0196-3635(199811/12)19:6<667:SMEBNO>2.0.ZU;2-M
Abstract
The effects of nitric oxide (NO) on sperm motility were examined in the fat head minnow, Pimephelas promelas, using computer-assisted sperm analysis (C ASA). The observed effects underscore the dual nature of NO as both a low-c oncentration regulatory agent and, at higher doses, a cytotoxic agent. At 1 x 10(-6) M concentration, NO donor sodium nitroprusside (SNP) enhanced spe rm motility percentages and increased CASA velocity parameters curvilinear velocity, straight-line velocity, and average path velocity, whereas 1 x 10 (-2) M concentration inhibited percent motility and decreased velocities. F athead minnow ova-produced NO was subsequently trapped as a paramagnetic fe rrous iron complex and detected by electron spin resonance spectroscopy. Th e distinctive triplet spectrum, with a(N) = 12.5G and g(iso) = 2.04, was re corded during a critical 5-minute period following laying. Nitric oxide syn thase (NOS) was histochemically localized at the micropyle of mature unfert ilized fathead eggs, and an inhibitor of NOS blocked histochemical staining . CASA analysis of sperm motility in the presence of ova-produced NO over a n 8-minute time course reveals an optimum motility enhancement at 4 minutes that is similar to the effect of 1 x 10(-6) M SNP. This transient NO produ ction by freshly laid ova and the localization of NOS near the site of sper m entry, together with the motility-enhancing effect of 1 x 10(-6) M SNP on sperm, indicates an active role for low-concentration NO in fertilization.