Physiological response of bovine subcommissural organ to endothelin 1 and bradykinin

The circumventricular organs (CVOs) regulate certain vegetative functions. Receptors for bradykinin (BDK) and endothelin (ET) have been found in some CVOs. The subcommissural organ (SCO) is a CVO expressing BDK-B2 receptors and secreting Reissner's fiber (RF) glycoproteins into the cerebrospina...

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Bibliographic Details
Published in:Cell and tissue research 2009-06, Vol.336 (3), p.477-488
Main Authors: Schöniger, S, Caprile, T, Yulis, C. R, Zhang, Q, Rodríguez, E. M, Nürnberger, F
Format: Article
Language:English
Subjects:
Adenosine Triphosphate - pharmacology
Animals
Autoradiography
Biochemistry
Biomedical and Life Sciences
Biomedicine
Body fluids
Bradykinin - pharmacology
Calcium Signaling - drug effects
Cattle
Cell Adhesion Molecules, Neuronal - pharmacology
Cellular biology
Endothelin-1 - pharmacology
Glycoproteins
Human Genetics
Molecular Medicine
Proteomics
Receptors, Endothelin - metabolism
Regular Article
Subcommissural Organ - cytology
Subcommissural Organ - drug effects
Subcommissural Organ - physiology
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Summary:The circumventricular organs (CVOs) regulate certain vegetative functions. Receptors for bradykinin (BDK) and endothelin (ET) have been found in some CVOs. The subcommissural organ (SCO) is a CVO expressing BDK-B2 receptors and secreting Reissner's fiber (RF) glycoproteins into the cerebrospinal fluid. This investigation was designed to search for ET receptors in the bovine SCO and, if found, to study the functional properties of this ET receptor and the BDK-B2 receptor. Cryostat sections exposed to ¹²⁵I ET1 showed dense labeling of secretory SCO cells, whereas the adjacent ciliated ependyma was devoid of radiolabel. The binding of ¹²⁵I ET1 was abolished by antagonists of ETA and ETB receptors. The intracellular calcium concentration ([Ca²⁺]i) was measured in individual SCO cells prior to and after exposure to ET1, BDK, or RF glycoproteins. ET1 (100 nM) or BDK (100 nM) caused an increase in [Ca²⁺]i in 48% or 53% of the analyzed SCO-cells, respectively. RF glycoproteins had no effect on [Ca²⁺]i in SCO cells. ET and BDK evoked two types of calcium responses: prolonged and short responses. Prolonged responses included those with a constant slow decline of [Ca²⁺]i, biphasic responses, and responses with a plateau phase at the peak level of [Ca²⁺]i. ET1-treated SCO explants contained a reduced amount of intracytoplasmic AFRU (antiserum to RF glycoproteins)-immunoreactive material compared with sham-treated control explants. Our data suggest that ET1 and BDK regulate [Ca²⁺]i in bovine SCO cells, and that the changes in [Ca²⁺]i influence the secretory activity of these cells.
ISSN:0302-766X
1432-0878
DOI:10.1007/s00441-009-0792-z