OBJECTIVES: The underlying pathophysiological mechanism leading to raised blood pressure after treatment with erythropoietin is a point of much discussion. Direct vasopressor effects of erythropoietin have been shown recently. The aim was to determine whether erythropoietin effects cytosolic free calcium concentration ([Ca2+]i in vascular smooth muscle cells. METHODS: The effect of erythropoietin on ([Ca2+]i was measured with the fluorescent dye fura2 in cultured vascular smooth muscle cells from Wistar Kyoto rats. RESULTS: Mean resting [Ca2+]i was 90.8(SEM 5.6) nM (n = 32). Addition of erythropoietin at concentrations of 100 U.ml-1 and 250 U.ml-1 increased [Ca2+]i to 112.3(5.0) nM (n = 23, p < 0.05) and 128.4(4.0) nM (n = 10, p < 0.01), respectively. Preincubation with erythropoietin caused a dose dependent increase in angiotensin II induced changes of [Ca2+]i in vascular smooth muscle cells. CONCLUSIONS: One mechanism of erythropoietin induced hypertension may be an increase in [Ca2+]i in vascular smooth muscle cells.
OBJECTIVES: The underlying pathophysiological mechanism leading to raised blood pressure after treatment with erythropoietin is a point of much discussion. Direct vasopressor effects of erythropoietin have been shown recently. The aim was to determine whether erythropoietin effects cytosolic free calcium concentration ([Ca2+]i in vascular smooth muscle cells. METHODS: The effect of erythropoietin on ([Ca2+]i was measured with the fluorescent dye fura2 in cultured vascular smooth muscle cells from Wistar Kyoto rats. RESULTS: Mean resting [Ca2+]i was 90.8(SEM 5.6) nM (n = 32). Addition of erythropoietin at concentrations of 100 U.ml-1 and 250 U.ml-1 increased [Ca2+]i to 112.3(5.0) nM (n = 23, p < 0.05) and 128.4(4.0) nM (n = 10, p < 0.01), respectively. Preincubation with erythropoietin caused a dose dependent increase in angiotensin II induced changes of [Ca2+]i in vascular smooth muscle cells. CONCLUSIONS: One mechanism of erythropoietin induced hypertension may be an increase in [Ca2+]i in vascular smooth muscle cells.
Authors: K Noguchi; S Yamashiro; T Matsuzaki; M Sakanashi; J Nakasone; K Miyagi; M Sakanashi Journal: Br J Pharmacol Date: 2001-06 Impact factor: 8.739
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