Abstract
Gamma-aminobutyric acid (GABA) concentrations in seminal plasma and washed spermatozoa from normal donors were assessed by a sensitive radioreceptor assay, and were detectable in both fractions. Specific binding of [3H]-muscimol was shown to be dependent on protein concentration, temperature and incubation time. [3H]-muscimol specific binding to human sperm membranes was significantly inhibited by the GABA type A receptor (GABA(A)) antagonist, bicuculline, and by the GABA(A) agonists, muscimol and isoguvacine, but not by the GABA type B receptor (GABA(B)) agonist baclofen. Scatchard analysis of [3H]-muscimol binding yielded a linear plot consistent with a single population of binding sites with a dissociation constant in the low nanomolar range. Incubation with GABA at a high micromolar concentration for 3 h under capacitating conditions resulted in an increase in the percentage of spermatozoa showing hyperactivated motility as assessed by computerized motility analyser. However, low micromolar concentrations of the GABA(A) agonist, muscimol, were sufficient to significantly increase sperm hyperactivity. These results suggest that the effect of GABA on human sperm motility might be mediated through a specific GABA(A) receptor.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
