Specific strychnine binding sites on acrosome-associated membranes of golden hamster spermatozoa

Biochem Biophys Res Commun. 2003 Jun 27;306(2):376-81. doi: 10.1016/s0006-291x(03)00981-1.

Abstract

This study demonstrates for the first time, that membrane vesicles originated from the hamster sperm head after the occurrence of the acrosome reaction, possess specific strychnine binding sites. [3H]Strychnine binding was saturable and reversible, being displaced by unlabeled strychnine (IC(50)=26.7+/-2.3 microM). Kinetic analysis revealed one binding site with K(d)=120nM and B(max)=142fmol/10(6) spermatozoa. Glycine receptor agonists beta-alanine and taurine inhibited strychnine binding by 20-30%. Surprisingly, glycine stimulated binding by about 40-50%. Results obtained in this study strongly suggest the presence of glycine receptors-with distinctive kinetic properties on the periacrosomal plasma membrane of hamster spermatozoa. Localization of this receptor fits well with its previously proposed role in acrosomal exocytosis during mammalian fertilization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrosome Reaction*
  • Animals
  • Binding Sites
  • Binding, Competitive
  • Convulsants / pharmacology
  • Cricetinae
  • Dose-Response Relationship, Drug
  • Fertilization
  • Glycine / pharmacology
  • Inhibitory Concentration 50
  • Kinetics
  • Male
  • Mesocricetus
  • Protein Binding
  • Sperm Motility
  • Spermatozoa / metabolism*
  • Strychnine / chemistry*
  • Taurine / pharmacology
  • beta-Alanine / pharmacology

Substances

  • Convulsants
  • beta-Alanine
  • Taurine
  • Strychnine
  • Glycine