Browsing by Subject "Cholecystokinin"

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    Cholecystokinin, acting through the A receptor subtype, stimulates the proliferative activity of adrenocortical cells and thymocytes in the ra
    (Murcia : F. Hernández, 1999) Malendowicz, L.K.; Tretjer, M.; De Caro, Raffaelle; Jedrzejczak, N.; Brelinska, R.; Markowska, A.; Nussdorfer, G.G.; Nowak, M.
    Cholecystokinin (CCK) is a multifunctional regulatory peptide, which acts through two main subtypes of receptors, named CCK-A and CCK-B. Evidence indicates that CCK modulates cell proliferation in various tissues in a paracrine manner, and proofs are available of the presence of CCK in both adrenal glands and thymus. Hence, we have investigated the possible mitogenic action of this peptide on these two tissues, by evaluating the %o of metaphase-arrested cells after vincristin injection (mitotic index). The systemic administration of CCK (three subcutaneous injections of 20 nmollkg, 28, 16 and 4 h before the sacrifice) increased the mitotic index in both the outer adrenal and thymus cortexes of immature (20-day-old) rats and the enucleated adrenal gland of adult (2-month-old) animals at day 5 and 8 of regeneration. The simultaneous administration of equimolar doses of a selective CCK-A receptor antagonist blocked the effect of CCK, while a CCK-B antagonist was ineffective. These findings indicate that CCK exerts a marked CCK-A-mediated proliferogenic effect on both adrenal cortex and thymus in the rat, the physiological relevance of which, however, remains to be demonstrated. In fact, the administration of the CCK-A antagonist alone was ineffective, thereby casting doubts on the role played by endogenous CCK in the maintenance and stimulation of adrenal and thymus growth.
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    coexistence of serotonin and cholecystokinin in paraneurons of the foetal sheep lung
    (Murcia : F. Hernández, 1994) Balaguer, L.; Romano, J.; Ruíz-Pesini, P.
    The coexistence of serotonin and cholecystokinin was studied in foetal sheep lungs at pseudoglandular stage of developtnerit by light inicroscopic itninunohistochemistry. The coexistence was examined by staining consecutive sections with the different antibodies. Serotonin and cholecystokinin iniinunoreactivity was found within consecutive sections of most bronchopultnonary neuroepithelial bodies and in consecutive sections of the same intrapulmonary autonomic gariglia.
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    Studies on the involvement Histology and Histopathology Cellular and Molecular Biology of endogenous neuropeptides in the control of thymocyte proliferation in the rat
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2001) Trejter, M.; Warchol, J. B.; de Caro, R.; Brelinska, R.; Nussdorfer, G. G.; Malendowicz, L. K.
    The possible involvement of endogenous vasoactive intestinal peptide (VIP), cholecystokinin (CCK) and neurotensin (NT) in the control of thymocyte proliferation ha s been investigated in vivo in the immature rat. For this task, we have studied the effects of the administration of selective antagonists of the receptors of the three neuropeptides on the mitotic index (%0 of metaphase-arrested cells after vincristin injection) of thymocytes. Both CCK- and TN-receptor antagonists were ineffective. In contrast, two VIP receptor antago nists (VIP-As) enhanced the mitotic index of thymocytes. VIP reversed the effect of VIP-As, but when administered alone it did not alter the mitotic activity of thymocytes. In light of these findings, we conclude that endogenous VIP exerts a maximal tonic inhibitory influence on the basal proliferative activity of rat thymocytes, while endogenous CCK and NT do not play a relevant modulatory role in thi process.