Gamma-Aminobutyric Acid, Its Related Enzymes and Receptor-Binding Sites in the Human Ovary and Fallopian Tube

Abstract

The concentration of Γ-aminobutyric acid (GABA), the activities of related enzymes, i.e. glutamate decarboxylase and GABA transaminase, as well as the level of specific GABA binding sites were determined in ovaries and fallopian tubes obtained surgically from 31 women. None of the biochemical parameters examined showed a correlation with the age and hormonal background (serum estradiol and progesterone levels) of the patients. The respective ovarian and tubal values did not differ significantly in groups operated on because of uterine myoma and carcinoma. In organs from pregnant women, however, most GABAergic markers altered significantly. These findings indicate some gestation-related role for the ovarian and tubal GABA systems in humans.

GABA, progesterone and zona pellucida activation of PLA2 and regulation by MEK‐ERK1/2 during acrosomal exocytosis in guinea pig spermatozoa

“…Inclusion of 80 lM ATA abrogated all these responses (Fig. 3A-D), further confirming the involvement of PLA 2 .…”

“…Staurosporine, at the low concentration used in this study, may be acting on PKC and the effect is similar to that seen with chelerythrine chloride (another, more specific PKC inhibitor) on PLA 2 and exocytosis stimulated by progesterone or ZP [22]. 2 is regulated by the MEK-ERK1/2 pathway In a previous study, we found that progesterone-and ZP-induced PLA 2 activation is regulated by PKA and PKC [22]. Here, we tested in two series of experiments whether PLA 2 activation and exocytosis induced by GABA, progesterone or ZP is regulated by the MEK-ERK1/2 pathway.…”

“…ATA inhibits GABA-and progesterone-induced PLA 2 activity and acrosomal exocytosis To test whether GABA-stimulated acrosomal exocytosis involves PLA 2 activation, capacitated guinea pig spermatozoa were pre-exposed to ATA, an effective inhibitor of sperm PLA 2 [21,39], before stimulation. Inclusion of ATA significantly inhibited GABA-induced acrosomal exocytosis in a concentration-dependent fashion (Fig.…”

“…GABA specific receptor sites and a GABA uptake system are present in the female genital tract of the rat and rabbit [1], and the human uterus, oviduct and ovary [2]. In addition, high concentrations of GABA exist in seminal plasma [3,4].…”

“…Gamma‐aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian central nervous systems (CNS), although GABAergic systems are also found in various peripheral tissues, including the female reproductive organs. GABA specific receptor sites and a GABA uptake system are present in the female genital tract of the rat and rabbit [1], and the human uterus, oviduct and ovary [2]. In addition, high concentrations of GABA exist in seminal plasma [3,4].…”