title: Suppression of progesterone-enhanced hyperactivation in hamster spermatozoa by γ-aminobutyric acid.
abstract: It has been recently shown that mammalian spermatozoa were hyperactivated by steroids, amines and amino acids. In the present study, we investigated whether hyperactivation of hamster sperm is regulated by progesterone (P) and γ-aminobutyric acid (GABA). Although sperm hyperactivation was enhanced by P, GABA significantly suppressed P-enhanced hyperactivation in a dose-dependent manner. Suppression of P-enhanced hyperactivation by GABA was significantly inhibited by an antagonist of the GABAA receptor (bicuculline). Moreover, P bound to the sperm head, and this binding was decreased by GABA. Because the concentrations of GABA and P change in association with the estrous cycle, these results suggest that GABA and P competitively regulate the enhancement of hyperactivation through the GABAA receptor.
authors.affiliation: Laboratory Animal Research Center, Dokkyo Medical University, Tochigi 321-0293, Japan.
authors.forename: Hiroe
authors.initials: H
authors.lastname: Kon
authors.forename: Gen L
authors.initials: GL
authors.lastname: Takei
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Fujinoki
authors.forename: Motoo
authors.initials: M
authors.lastname: Shinoda
mesh_terms: D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D006224:Cricetinae; D004336:Drug Antagonism; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D008297:Male; D008647:Mesocricetus / Q000502:physiology; D011374:Progesterone / Q000494:pharmacology*; D011963:Receptors, GABA-A / Q000502:physiology; D013075:Sperm Capacitation / Q000187:drug effects*; D013081:Sperm Motility / Q000187:drug effects*; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
chemical_list: D058787:GABA-A Receptor Antagonists; D011963:Receptors, GABA-A; D011374:Progesterone; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline