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Danas je široko prihvaćeno mišljenje da je progresivno smanjenje efikasnosti timopoeze, koje počinje u pubertetu, kauzalno povezano sa porastom koncentracije polnih hormona. Pored toga, i koncentracija kateholamina, toničnih inhibitora timopoeze posredstvom β-adrenergičih receptora, se u timusu povećava, počevši od pubertetnog perioda. Poznato je da zrele ćelije imunskog sistema (T-limfociti, makrofage i dendritske ćelije), i različiti tipovi epitelnih ćelija, imaju sposobnost sinteze kateholamina. Konačno, u različitim tkivima, muški polni hormoni utiču na sintezu kateholamina i ispoljavanje β-adrenergičkih receptora. Ova saznanja su nužno nametnula pitanje da li timociti i/ili ćelije strome timusa poseduju sposobnost sinteze kateholamina, i, ukoliko je odgovor potvrdan, da li i u kojim tipovima ćelija timusa hormoni testisa utiču na sintezu kateholamina i/ili ispoljavanje β2-adrenergičkog receptora i time, moguće, na modulatorno delovanje kateholamina na proces timopoeze. Imajući u vidu sve prethodno navedene nalaze, postavljeni su ciljevi ove disertacije: 1) da se utvrdi da li timociti i/ili ćelije strome timusa odraslih mužjaka pacova sintetišu kateholamine, i da se precizno definišu tipovi ćelija u ovom organu koji ispoljavaju β2-adrenergički receptor, 2) da se ispita da li orhidektomija u uzrastu od 30 dana, kada je timus pacova najosetljiviji na efekte kastracije, utiče na koncentraciju kateholamina i ispoljavanje β2-adrenergičkog receptora u timusu odraslih pacova, i, ako je odgovor potvrdan, 3) da se utvrdi da li se modulatorno delovanje kateholamina na timopoezu razlikuje kod orhidektomisanih i neorhidektomisanih životinja. Nađeno je da timociti, timusne epitelne ćelije i makrofage sadrže i sintetišu kateholamine. Osim toga, subpopulacije ovih tipova ćelija, takođe, ispoljavaju β2- adrenergički receptor. Orhidektomija u uzrastu od 30 dana je smanjila koncentraciju noradrenalina u timusu odraslih životinja, usled smanjenja gustine noradrenergičkih nervnih v, It is widely accepted that the progressive decline in the efficiency of thymopoiesis, starting at puberty, is causally related to increasing concentrations of gonadal hormones. In addition, thymic level of catecholamines, which act, via β- adrenoceptors, as tonic inhibitors of thymopoiesis, increases around puberty. There is a pile of evidence that mature immune cells (T-lymphocytes, macrophages and dendritic cells) as well as different types of epithelial cells, synthesize catecholamines. Furthermore, it has been shown that in various tissues male gonadal hormones affect catecholamine synthesis and β-adrenoceptor expression. These findings imposed the question whether thymocytes and/or thymic stromal cells synthesize catecholamines, and, if so, whether testicular hormones influence the synthesis of catecholamines and/or expression of β2-adrenoceptors, and possibly, consequently, the modulatory action of catecholamines on thymopoiesis. Considering all the aforementioned, the dissertation was aimed to: 1) explore whether thymocytes and/or thymic stromal cells in adult male rats synthesize catecholamines, and to define the types of thymic cells expressing β2-adrenoceptor; 2) examine whether orchidectomy at the age of 30 days, when rat thymus is the most sensitive to testicular hormone deprivation, affects catecholamine levels and β2- adrenoceptor expression in the thymus of adult rats, and, if so, 3) determine whether the modulatory effects of catecholamines on thymopoiesis differ in orchidectomized and non-orchidectomized animals. It has been found that thymocytes, thymic epithelial cells and macrophages in adult rats contain and synthesize catecholamines. In addition, it was shown that subsets of these cells also express the β2-adrenoceptors. Orchidectomy at the age of 30 days decreased the concentration of noradrenaline in the thymus of adult animals by diminishing the density of noradrenergic nerve fibers and catecholamine-containing thymic stromal cells and their

It is widely accepted that the progressive decline in the efficiency of thymopoiesis, starting at puberty, is causally related to increasing concentrations of gonadal hormones. In addition, thymic level of catecholamines, which act, via β- adrenoceptors, as tonic inhibitors of thymopoiesis, increases around puberty. There is a pile of evidence that mature immune cells (T-lymphocytes, macrophages and dendritic cells) as well as different types of epithelial cells, synthesize catecholamines. Furthermore, it has been shown that in various tissues male gonadal hormones affect catecholamine synthesis and β-adrenoceptor expression. These findings imposed the question whether thymocytes and/or thymic stromal cells synthesize catecholamines, and, if so, whether testicular hormones influence the synthesis of catecholamines and/or expression of β2-adrenoceptors, and possibly, consequently, the modulatory action of catecholamines on thymopoiesis. Considering all the aforementioned, the dissertation was aimed to: 1) explore whether thymocytes and/or thymic stromal cells in adult male rats synthesize catecholamines, and to define the types of thymic cells expressing β2-adrenoceptor; 2) examine whether orchidectomy at the age of 30 days, when rat thymus is the most sensitive to testicular hormone deprivation, affects catecholamine levels and β2- adrenoceptor expression in the thymus of adult rats, and, if so, 3) determine whether the modulatory effects of catecholamines on thymopoiesis differ in orchidectomized and non-orchidectomized animals. It has been found that thymocytes, thymic epithelial cells and macrophages in adult rats contain and synthesize catecholamines. In addition, it was shown that subsets of these cells also express the β2-adrenoceptors. Orchidectomy at the age of 30 days decreased the concentration of noradrenaline in the thymus of adult animals by diminishing the density of noradrenergic nerve fibers and catecholamine-containing thymic stromal cells and their, Danas je široko prihvaćeno mišljenje da je progresivno smanjenje efikasnosti timopoeze, koje počinje u pubertetu, kauzalno povezano sa porastom koncentracije polnih hormona. Pored toga, i koncentracija kateholamina, toničnih inhibitora timopoeze posredstvom β-adrenergičih receptora, se u timusu povećava, počevši od pubertetnog perioda. Poznato je da zrele ćelije imunskog sistema (T-limfociti, makrofage i dendritske ćelije), i različiti tipovi epitelnih ćelija, imaju sposobnost sinteze kateholamina. Konačno, u različitim tkivima, muški polni hormoni utiču na sintezu kateholamina i ispoljavanje β-adrenergičkih receptora. Ova saznanja su nužno nametnula pitanje da li timociti i/ili ćelije strome timusa poseduju sposobnost sinteze kateholamina, i, ukoliko je odgovor potvrdan, da li i u kojim tipovima ćelija timusa hormoni testisa utiču na sintezu kateholamina i/ili ispoljavanje β2-adrenergičkog receptora i time, moguće, na modulatorno delovanje kateholamina na proces timopoeze. Imajući u vidu sve prethodno navedene nalaze, postavljeni su ciljevi ove disertacije: 1) da se utvrdi da li timociti i/ili ćelije strome timusa odraslih mužjaka pacova sintetišu kateholamine, i da se precizno definišu tipovi ćelija u ovom organu koji ispoljavaju β2-adrenergički receptor, 2) da se ispita da li orhidektomija u uzrastu od 30 dana, kada je timus pacova najosetljiviji na efekte kastracije, utiče na koncentraciju kateholamina i ispoljavanje β2-adrenergičkog receptora u timusu odraslih pacova, i, ako je odgovor potvrdan, 3) da se utvrdi da li se modulatorno delovanje kateholamina na timopoezu razlikuje kod orhidektomisanih i neorhidektomisanih životinja. Nađeno je da timociti, timusne epitelne ćelije i makrofage sadrže i sintetišu kateholamine. Osim toga, subpopulacije ovih tipova ćelija, takođe, ispoljavaju β2- adrenergički receptor. Orhidektomija u uzrastu od 30 dana je smanjila koncentraciju noradrenalina u timusu odraslih životinja, usled smanjenja gustine noradrenergičkih nervnih v