title: Effect of serotonin on cytosolic free calcium in adrenal glomerulosa and vascular smooth muscle cells.
abstract: In view of its vasoconstricting action and of its stimulating effect on aldosterone biosynthesis, serotonin (5-hydroxytryptamine, 5-HT) could play a role in the genesis and/or maintenance of hypertension. The effects are mediated by different specific receptors whose transmembrane signaling system is not elucidated. We have used the fluorescent probe quin 2 to study the effect of 5-HT on cytosolic free calcium in enzymatically dispersed bovine adrenal glomerulosa cells and in cultured rat aortic smooth muscle cells. We also examined the effect of 5-HT on prostacyclin production by rat aortic smooth muscle cells. Serotonin did not modify the level of cytosolic free calcium in adrenal glomerulosa cells. In contrast, serotonin induced rapid, concentration-dependent (10(-8) -10(-5) M) rises of cytosolic free calcium in monolayers of cultured rat aortic smooth muscle cells, from a basal level of 153 +/- 27 nM to peak levels of about 400 nM. Ketanserin (10(-6) M), a specific 5-HT2-receptor antagonist completely blocked the free calcium rise induced by 5-HT. 5-HT induced a concentration-dependent increase in 6-keto-PGF1 alpha production in smooth muscle cells, which was suppressed by ketanserin, indomethacin or removal of calcium from the incubation medium. In contrast nifedipine (10(-6) M) did not modify the response to 5-HT while it abolished the response to vasopressin and did not modify the response to angiotensin II. We conclude that the 5-HT receptors of adrenal glomerulosa cells and vascular smooth muscle cells are linked to two distinct signalling systems which mediate the different biological responses.
authors.affiliation: Division of Endocrinology, University Hospital, Geneva, Switzerland.
authors.forename: A M
authors.initials: AM
authors.lastname: Capponi
authors.forename: P D
authors.initials: PD
authors.lastname: Lew
authors.forename: M B
authors.initials: MB
authors.lastname: Vallotton
mesh_terms: D015121:6-Ketoprostaglandin F1 alpha / Q000378:metabolism; D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D011464:Epoprostenol / Q000378:metabolism; D066298:In Vitro Techniques; D007650:Ketanserin / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D051381:Rats; D012701:Serotonin / Q000494:pharmacology*
chemical_list: D012701:Serotonin; D015121:6-Ketoprostaglandin F1 alpha; D007650:Ketanserin; D011464:Epoprostenol; D009543:Nifedipine; D002118:Calcium