Local serotonergic signaling in mammalian follicles, oocytes and early embryos

ArticleinLife Sciences 81(25-26):1627-37 · January 2008with7 Reads
DOI: 10.1016/j.lfs.2007.09.034 · Source: PubMed
Abstract
The involvement of neurotransmitters in mammalian female reproductive tissues has been the object of several studies in past decades. This review focuses on new evidence that serotonin (or 5-hydroxytryptamine, 5-HT) may be an important key player, acting locally in mammalian ovaries and female genital tracts where it may influence granulosa and cumulus cells as well as oocytes and early embryos. Pioneering studies reporting 5-HT in ovaries and other female reproductive tissues and cells are now complemented by the identification of specific 5-HT receptor subtypes (5-HT(1D), 5-HT(2A-B) and 5-HT(7)) in granulosa or cumulus cells, oocytes and early embryos. Additional serotonergic players, including the 5-HT transporter (SERT or Slc6A4) expressed in oocytes and embryos, and the 5-HT-producing enzyme tryptophan hydroxylase-1 (TPH1) expressed in cumulus cells, now make up a complete and autonomous local serotonergic network. Direct demonstrations of intracellular Ca(2+) and cAMP signaling by 5-HT in cumulus cells and its capacity to regulate progesterone secretion by granulosa cells further illustrate some of its potential functions in ovarian physiology. Recent evidence shows that mouse mothers with knocked-out TPH1 have embryos with impaired early development, establishing that maternal 5-HT is required for normal embryonic development. This local regulation of reproductive processes by 5-HT in mammals might have derived from better-known, and possibly ancestral, serotonergic networks similarly at play in several primitive animals, and potential implications for human reproduction may also be foreseen. Specific roles played by 5-HT in mammalian reproduction remain to be further investigated, and now span from steroidogenesis and oocyte maturation to early embryonic development.
    • "It is possible that the increase in the concentration of 5-HT observed in the ovaries of the FLX-treated rats resulted from the direct inhibition of SERT, the target protein for FLX, in this organ [20]. In mice, SERT was detected in oocytes and cumulus cell complexes [4,10,42]. These results support the idea that the 5-HT accumulation in the ovaries is the result of the inhibition of SERT activity. "
    [Show abstract] [Hide abstract] ABSTRACT: Fluoxetine (FLX), a selective serotonin reuptake inhibitor is an antidepressant in the treatment of mood disorders. Its impact on reproductive processes is incompletely known. The present study analyzed the reproductive effects of FLX in prepubertal female rats. Two experiments were conducted. First (acute administration), 30-day-old female rats were injected intraperitoneally with 5 mg/kg of fluoxetine-hydrochloride, and were terminated 24, 48 or 72 h after the treatment. Second (subchronic administration), FLX was injected on days 30-33 of age, and the animals were terminated the day of first estrus. In acute treatment estradiol concentration increased to 72 h. In subchronic treatment increased serotonin concentration in ovaries and decreased the number of ova shed. An increase in number of atretic follicles and oocyte fragmentation was observed in these animals. The results suggest that FLX acts on the ovary or hypothalamus–pituitary axis resulting in modifications of the follicular development and ovulation.
    Full-text · Article · Jun 2016
    • "These results suggest that either dopamine receptors are functionally active in early P. lividus development together with serotonin ones, or that embryonic receptors have combined sensitivity to both of these transmitters. Simultaneous expression of the receptors of different transmitters coupled to the same system of second messengers is characteristic for early development of some other animals (Dubé & Amireault, 2007; Nikishin et al., 2012a). Moreover, various types of GPCRs may interact and thus change their functional properties (Kamal & Jockers, 2011). "
    [Show abstract] [Hide abstract] ABSTRACT: Reverse-transcription polymerase chain reaction (RT-PCR) investigation of the expression of the components supposedly taking part in serotonin regulation of the early development of Paracentrotus lividus has shown the presence of transcripts of five receptors, one of which has conservative amino acid residues characteristic of monoaminergic receptors. At the early stages of embryogenesis the expressions of serotonin transporter (SERT) and noradrenaline transporter (NET) were also recognized. The activities of the enzymes of serotonin synthesis and serotonin transporter were shown using immunohistochemistry and incubation with para-chlorophenylalanine (PСРА) and 5-hydroxytryptophan (HTP). Pharmacological experiments have shown a preferential cytostatic activity of ligands characterized as mammalian 5-hydroxytryptamine (5-HT) 1 -antagonists. On the basis of the sum of the data from molecular biology and embryo physiological experiments, it is suggested that metabotropic serotonin receptors and membrane transporters take part in the regulatory processes of early sea urchin embryogenesis.
    Full-text · Article · Apr 2015
    • "Anatomical studies have shown that in the hypothalamus, the GnRH-producing neurons receive innervation by the serotoninergic system (Smith and Jennes 2001), which modulates GnRH secretion. Different studies have confirmed the presence of serotonin in the hypophysis (Westlund and Childs 1982; Payette et al. 1985; Carvajal et al. 1991; Vanhatalo and Soinila 1995) and the gonads (Veselá et al. 2003; Dubé and Amireault 2007). In the ovary, several elements of the serotoninergic system are present (Veselá et al. 2003; Dubé 2005a, 2005b). "
    Full-text · Dataset · Apr 2015 · Zygote
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