Does kisspeptin participate in GABA-mediated modulation of GnRH and GnRH receptor biosynthesis in the hypothalamic-pituitary unit of follicular-phase ewes?
| Autor: | Marek Brytan, F. Przekop, Bożena Antkowiak, Magdalena Ciechanowska, Marek Kowalczyk, Magdalena Łapot, Tadeusz Malewski |
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| Rok vydání: | 2018 |
| Předmět: |
endocrine system
medicine.medical_specialty Hypothalamo-Hypophyseal System Estrous Cycle Bicuculline Gonadotropin-Releasing Hormone 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Kisspeptin Anterior pituitary Internal medicine medicine Animals GABA-A Receptor Agonists GABA-A Receptor Antagonists Pharmacology Neurons Kisspeptins Sheep Muscimol GNRHR General Medicine Receptors GABA-A Preoptic area medicine.anatomical_structure Endocrinology nervous system chemistry Hypothalamus 030220 oncology & carcinogenesis Median eminence Female hormones hormone substitutes and hormone antagonists 030217 neurology & neurosurgery Receptors LHRH medicine.drug |
| Zdroj: | Pharmacological reports : PR. 71(4) |
| ISSN: | 2299-5684 |
| Popis: | Background The inverse relationship between GnRH transcript level and GABA neurons activity has suggested that GABA at the hypothalamic level may exert a suppressive effect on subsequent steps of the GnRH biosynthesis. In the present study, we analyzed the effects of GABA type A receptor agonist (muscimol) or antagonist (bicuculline) on molecular mechanisms governing GnRH/LH secretion in follicular-phase sheep. Methods ELISA technique was used to investigate the effects of muscimol and/or bicuculline on levels of post-translational products of genes encoding GnRH ligand and GnRH receptor (GnRHR) in the preoptic area (POA), anterior (AH) and ventromedial (VMH) hypothalamus, stalk/median eminence (SME), and GnRHR in the anterior pituitary (AP). Real-time PCR was chosen for determination of the effect of drugs on kisspeptin (Kiss 1) mRNA level in POA and VMH including arcuate nucleus (VMH/ARC), and on Kiss1 receptor (Kiss1r) mRNA abundance in POA-hypothalamic structures. These analyses were supplemented by RIA method for measurement of plasma LH concentration. Results The study demonstrated that muscimol and bicuculline significantly decreased or increased GnRH biosynthesis in all analyzed structures, respectively, and led to analogous changes in plasma LH concentration. Similar muscimol- and bicuculline-related alterations were observed in levels of GnRHR. However, the expression of Kiss 1 and Kiss1r mRNAs in selected POA-hypothalamic areas of either muscimol- and bicuculline-treated animals remained unaltered. Conclusions Our data suggest that GABAergic neurotransmission is involved in the regulatory pathways of GnRH/GnRHR biosynthesis and then GnRH/LH release in follicular-phase sheep conceivably via indirect mechanisms that exclude involvement of Kiss 1 neurons. |
| Databáze: | OpenAIRE |
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