Suppression of Progesterone-enhanced Hyperactivation in Hamster Spermatozoa by γ-aminobutyric Acid
نویسندگان
چکیده
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.
منابع مشابه
Estrogen suppresses melatonin-enhanced hyperactivation of hamster spermatozoa
Hamster sperm hyperactivation is enhanced by progesterone, and this progesterone-enhanced hyperactivation is suppressed by 17β-estradiol (17βE2) and γ-aminobutyric acid (GABA). Although it has been indicated that melatonin also enhances hyperactivation, it is unknown whether melatonin-enhanced hyperactivation is also suppressed by 17βE2 and GABA. In the present study, melatonin-enhanced hyperac...
متن کاملγ-Aminobutyric acid suppresses enhancement of hamster sperm hyperactivation by 5-hydroxytryptamine
Sperm hyperactivation is regulated by hormones present in the oviduct. In hamsters, 5-hydroxytryptamine (5HT) enhances hyperactivation associated with the 5HT2 receptor and 5HT4 receptor, while 17β-estradiol (E2) and γ-aminobutyric acid (GABA) suppress the association of the estrogen receptor and GABAA receptor, respectively. In the present study, we examined the regulatory interactions among 5...
متن کاملChanges in Motility Parameters of Mouse Spermatozoa in Response to Different Doses of Progesterone during Course of Hyperactivation
The aim of this study was to evaluate changes that occur in motility parameters of progesterone treated mouse spermatozoa during course of hyperactivation. Mouse spermatozoa treated with different doses of progesterone were videotaped after 10 min and 90 min of incubation. For each sperm, one second of movement of the head-midpiece junction was traced from the videotape and for each tracing sev...
متن کاملEffects of Different Doses of Progesterone on Motion Parameters of Mouse Spermatozoa During the Course of Hyperactivation
Purpose: To evaluate the changes that occur in the motility parameters of progesterone treated sperms during the course of hyperactivation. Materials and Methods: Spermatozoa treated with different doses of progesterone were videotaped after 10 min and 90 min. For each sperm, 1 sec. of movement of the head-midpiece junction was traced from the videotape. For each tracing, seven motility parame...
متن کاملgamma-Aminobutyric acid (GABA) induces the acrosome reaction in human spermatozoa.
The sperm acrosome reaction takes place in response to progesterone and zona pellucida. Progesterone may act on more than one type of surface receptor, of which one is a gamma-aminobutyric acid (GABA) type A-like receptor. Although there is direct evidence of GABA initiation of mouse sperm acrosome reaction, there are conflicting results regarding GABA-induced exocytosis in human spermatozoa. W...
متن کامل