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Comparative development & evolution of adenohypophysis in basal fishes
Brezarová, Dominika ; Černý, Robert (advisor) ; Buchtová, Marcela (referee)
The pituitary is a master endocrine gland in the vertebrate head with many crucial roles in producing hormones and controlling secretion of other glands, and with long-standing controversies on its evolution and embryonic origin. Adenohypophysis (ADH), the front lobe of the pituitary, develops from the rostral placode that extensively migrates under the brain to connect the neurohypophysis, evagination of the ventral hypothalamus. Owing to its ectodermal placodal origin, ADH is commonly understood as a part of the vertebrate specific acquisition of our new head. Recently, however, an endodermal contribution to ADH was revealed in the teleost fish, supporting classic claims of a pre-vertebrate origin of this organ from an ancient chordate pharyngeal structure. In this work, early development of ADH was characterized in three species of basal fishes, bichirs, sturgeons, and gars, representing a possible stem-like pattern of early vertebrate craniogenesis. Interestingly, in all three species, both the early development and later migration of ADH is intimately linked with the pharyngeal domain in the rostral head. In sturgeon embryos, ADH migrates in between the brain and the pharyngeal domain, which further separates ADH from the forming mouth. In bichir embryos, ADH was additionally shown to get...
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Identification of new neuroactive steroids that are able to interact with allosteric binding sites on purinergic P2X receptors
Sivčev, Sonja ; Zemková, Hana (advisor) ; Vyklický, Vojtěch (referee) ; Stojilkovic, Stanko S. (referee)
(EN) Purinergic P2X receptors are ATP-gated cation channels with multiple physiological roles and are emerging as important therapeutic targets in a range of diseases. P2X subunit consists of two transmembrane helices (TM1 and TM2), an extracellular ATP-binding domain, and intracellular N- and C- termini. Seven different P2X subunits (P2X1-7) can assemble to form homotrimeric or heterotrimeric ion channels permeable for monovalent cations and calcium. P2X are ubiquitously expressed. Among them, P2X2, P2X4, and P2X7 are the most abundant within the brain. The activity of P2X depends not only on the presence of ATP but also on allosteric modulators that may inhibit or potentiate the activity of these channels. Our aim was to identify new molecules that could interact with allosteric binding sites on P2X receptors, design and synthesize new analogues of neurosteroids, and define crucial receptor domains and amino acids important for neurosteroid binding. By using a patch-clamp electrophysiology technique we recorded ATP-induced currents in HEK293T cells transfected with rat P2X2, P2X4, and P2X7, as well as in the rat anterior pituitary cells and hypothalamic neurons endogenously expressing these receptors. We found that 17β-ester derivatives of testosterone, namely testosterone butyrate and...
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The Role of Neuropeptides in Stress and in Pathophysiology of EAE
Kramáriková, Ivana ; Slanař, Ondřej (advisor) ; Slíva, Jiří (referee) ; Kmoníčková, Eva (referee)
Introduction and Aim: Neuropeptides are widely distributed group of biologically active substances and their effects depend on their activity and localization of specific receptors. The mechanism of the regulatory / modulatory effects of neuropeptides has not been fully elucidated yet, and these gaps in our knowledge make it difficult for them to influence them therapeutically. Our hypothesis was that similar to the effects of the galaninergic system on the cardiovascular system, the galaninergic system may be one of the important modulators of the hypothalamic-pituitary-adrenal axis and may therefore modulate the stress response or pathophysiology of selected neurological diseases. The aim of our study was to investigate presence and expression of CRH and Galanin receptors in the basal conditions and in stress in adenohypohysis and in hypophysis and in pathological conditions - in the spinal cords in the murine model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE) and determine GalR1 cellular localization (oligodendrocytes, microglia, astrocytes, ependymal cells, and endothelial cells in the capillaries). Results: The expression of all tested galaninergic peptides was determined in the adenohypophysis. It was found that the expression of the GalR2 mRNA in adenohypophysis...
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Comparative development & evolution of adenohypophysis in vertebrates
Brezarová, Dominika ; Černý, Robert (advisor) ; Kozmikova, Iryna (referee)
Adenohypophysis is very important gland in vertebrate head. In general adenohypophysal development is described together with formation of the primary mouth. Adenohypophyseal placode migrates together with stomodeal placode in ventral direction. Stomodeal placode starts to invaginate and from oral ectoderm adenohyphyseal placode invaginates to form Rathke's pouch. Pouch is then separated from mouth and migrates towards the brain to make adult hypohyseal gland. Origin of adenohypophysis is therefore in oral ectoderm, but in some vertebrates species is this development little different and adenohypophysis can even be endodermal. In some vertebrate groups, like amphibians or fishes there's no sign of Rathke's pouch, thus early migrations of adenohypophyseal placode can be different. These differences are there maybe because these groups don't have shallow invagination of stomodeum like other vertebrates. There are some homological structures in other chordate groups, for example Hatshek's pit in amphioxus or neural gland in tunicates, these structures has, in contrast with vertebrates, endodermal origin. Key words: adenohypohysis, placodes, primary mouth, craniofacial development, Rathke's pouch, vertebrates
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