SPERM NITRIC-OXIDE AND MOTILITY - THE EFFECTS OF NITRIC-OXIDE SYNTHASE STIMULATION AND INHIBITION

Citation
Et. Donnelly et al., SPERM NITRIC-OXIDE AND MOTILITY - THE EFFECTS OF NITRIC-OXIDE SYNTHASE STIMULATION AND INHIBITION, Molecular human reproduction, 3(9), 1997, pp. 755-762
Citations number
50
Categorie Soggetti
Reproductive Biology","Developmental Biology
ISSN journal
13609947
Volume
3
Issue
9
Year of publication
1997
Pages
755 - 762
Database
ISI
SICI code
1360-9947(1997)3:9<755:SNAM-T>2.0.ZU;2-8
Abstract
Nitric oxide (NO) is synthesized from L-arginine by a family of enzyme s known as the nitric oxide synthases (NOS). We have recently shown a NOS similar to constitutive brain NOS (bNOS) and endothelial NOS (ecNO S) to be present in spermatozoa. The aim of this study is to investiga te NO production by human spermatozoa and the effects of stimulation a nd inhibition of NOS. This was carried out using the Iso-NO, an isolat ed NO meter and sensor, which provides rapid, accurate and direct meas urements of NO. Semen samples with normozoospermic and asthenozoosperm ic profiles were prepared using a direct swim-up technique. Basal conc entrations of NO and stimulated NO production were measured after expo sure to the calcium ionophore (A23187; 0.01-10 mu M) a potent activato r of constitutive NOS. NO production in human spermatozoa was signific antly increased by the addition of A23187 30 seconds after stimulation . Furthermore, this response was greatly diminished by pre-incubating the samples with competitive inhibitors of L-arginine, the substrate f or NOS, before treatment with calcium ionophore, in the presence of N- G-nitro-L-arginine methyl ester (L-NAME), N-G-nitro-L-arginine (L-NA) or N-G-methyt-L-arginine (L-NMMA; all at 10 mu M), NO production was i nhibited with a rank order of potency L-NAME > L-NMMA > L-NA which is in accordance with the inhibition of an endothelial type of constituti ve NOS.