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Effect of ETB endothelin receptor on Na+–K+ ATPase activity in renal proximal tubule cells and its mechanisms
Abstracts
cells. Methods: The primary cultured VSMC cells were treated by norepinephrine (NE) with or without the presence of D3 receptor agonist, PD128907. The proliferation of VSMC cells was determined by [3H]-TdR incorporation. Result: NE dose-dependently increased proliferation of primary cultured VSMC cells from aorta of Sprague–Dawley rats, this effect was via α-adrenergic receptor, because α-adrenergic receptor blocker, phentolamine, blocked the stimulatory effect of NE on VSMC proliferation. D3 receptor agonist, PD128907, by itself (10− 8 mol/L or 10− 7 mol/L) had no effect, but reduced the stimulatory effect of NE on VSMC proliferation [NE10− 6 mol/L=6315±245 cpm vs. NE10− 6 mol/L+ PD128907 10− 8 mol/L = 5047 ± 331 cpm, P < 0.05;NE10− 6 mol/L = 6315 ± 245 cpm vs. NE10− 6 mol/L + PD128907 10− 7mol/L = 4898± 286 cpm, P<0.05]. Conclusion: Activation of D3 receptor reduces the stimulatory effect of NE on VSMC proliferation, which may take part into the pathogenesis of essential hypertension. doi:10.1016/j.ijcard.2009.09.236 EX000456 Effect of ETB endothelin receptor on Na+–K+ ATPase activity in renal proximal tubule cells and its mechanisms YAN LIU, ZHEN LI, DUOFEN HE, WEIBIN SHI, JIAN YANG, CHANGQING YU, CHUNYU ZENG Daping Hospital, The Third Military Medical University, China
EX000458 Effects of D1-like dopamine receptor on insulin receptor-mediated proliferation of vascular smooth muscle cells YU HAN, JIAN YANG, HEFEI HUANG, WEIBIN SHI, CHUNJIANG FU, DUOFEN HE, CHUNYU ZENG Daping Hospital, The Third Military Medical University, China Objective: To investigate the role of D1-like dopamine receptor on insulin receptor-mediated proliferation of vascular smooth muscle cells. Methods: A10 cells were used in this study and the mechanisms of D1-like receptor on insulin receptor were determined by immunoblotting. The proliferation of VSMC cells was determined by [3H]-TdR incorporation. Results: Insulin increased proliferation of A10 cells in a concentration-dependent manner. D1-like receptor, by itself, had no effect on cell proliferation, but blocked the insulin-mediated proliferation of A10 cells. Immunoblotting results showed that activation of D1like receptor by fenoldopam inhibited the insulin receptor expression, which might take part in the inhibitory effect of D1-like receptor on insulin receptor-mediated cell proliferation. Conclusion: Activation of D1-like receptor inhibits insulin receptor-mediated proliferation of vascular smooth muscle cells, which might be involved into the pathogenesis of essential hypertension. doi:10.1016/j.ijcard.2009.09.239
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Objective: To determine the effect of ETB receptor on Na –K ATPase activity in renal proximal tubule cells and its mechanisms. Methods: Immortalized renal proximal tubule (RPT) cells from WKY (Wistar–Kyoto) rat were used in this study, Na+–K+ ATPase activity was measured by oubain method. Result: Activation of ETB receptor concentration- and time-dependently decreased Na+–K+ ATPase activity. The maximal effect was about 36.1% at 15 min. Pre-treatment with Ca2+ blocker nicardipine (10− 6 M/15 min), blocked the inhibitory effects of ETB receptor in WKY RPT cells; and the inhibitory effects of ETB receptor on Na+–K+ ATPase activity were lost in Ca2+-free medium. Conclusion: ETB receptor plays an important role in decreasing Na+–K+ ATPase activity, Ca2+ entry is involved in this signal pathway. doi:10.1016/j.ijcard.2009.09.237 EX000457 Effect of insulin on D5 dopamine receptor expression and function in renal proximal tubule cells JIAN YANG, YU HAN, HEFEI HUANG, DUOFEN HE, CHUNYU ZENG Daping Hospital, The Third Military Medical University, China Objective: To investigate the effect of insulin on D5 dopamine receptor expression and function in renal proximal tubule (RPT). Methods: Immortalized RPT cells and D5 receptor transfected HEK293 (HEK-D5) cells were used in the study to investigate the effect of insulin on D5 receptor expression and function, and those effects were compared in RPT cells from Wistar–Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs). The function of D5 receptor was determined by measurement of the Na+–K+-ATPase activity in HEK-D5 cells. Results: Insulin increased D5 receptor protein expression in a concentration- and time-dependent manner in WKY RTPT cells, but not in SHRs. The basal level of D5 receptor expression was higher in WKY cells than that in SHR cells. Stimulation with fenoldopam (D1-like dopamine receptor agonist) inhibited the Na+–K+ATPase activity; pretreatment with insulin increased the inhibitory effect of fenoldopam on Na+–K+-ATPase activity in HEK-D5 cells. Conclusions: The abberant regulation of insulin on D5 receptor expression and function might be involved in the pathogenesis of essential hypertension. doi:10.1016/j.ijcard.2009.09.238
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EX000459 Inhibitory effect of D3 dopamine receptors on insulin receptor expression and function in vascular smooth muscle cells H.F. HUANGa, Y. Hana, D.F. HEa, L.D. ASICOb, P.A. JOSEb, C.Y. ZENGa Department of Cardiology, Daping Hospital, The Third Military Medical University, China b Center for Molecular Physiology Research, Children':s National Medical Center and Department of Pediatrics, George Washington University School of Medicine and Health Sciences, USA
a
Vascular smooth muscle cell (VSMC) proliferation, which is central to development of vascular diseases, including hypertension, is regulated by numerous hormones and humoral factors. Activation of the insulin receptor stimulates the VSMC proliferation while dopamine receptors, via D1 and D3 receptors, inhibit the stimulatory effects of norepinephrine on VSMC proliferation (Am J Physiol Heart Circ Physiol. 2008; 294: H2761–8). We hypothesize that there is an interaction between D3 dopamine and insulin receptors in VSMCs; stimulation of D3 receptor inhibits insulin receptor expression and function. We found that stimulation of the D3 dopamine receptor inhibited the insulin receptor expression in a concentration- and time-dependent manner in rat aortic A10 cells, an embryonic thoracic aortic smooth muscle cells from normotensive Berlin-Druckrey IX. The inhibitory effect was evident at 10− 7 M, noted as early as 2 h and maintained for at least 30 h. The inhibitory effect of D3 receptor on VSMC proliferation was blocked by PKA inhibitor (PKA inhibitor 14–22, 10− 6 M), indicating that PKA is involved into the signal pathway. There is a physiological significance of the interaction between D3 receptor and insulin receptors because the D3 receptor agonist, PD128907, by itself had no effect on VSMC proliferation, but reduced the stimulatory effect of insulin VSMC proliferation, determined by MTT assay (control = 0.3 ± 0.004, 10 − 7 M insulin = 0.6 ± 0.007; 10 − 7 M PD128907 + 10− 7 M insulin = 0.4 ± 0.01, P < 0.05, n = 9). The inhibitory effect of D3 receptor on insulin receptor expression and function also occurred in primary cultured VSMCs from Wistar– Kyoto rats and spontaneously hypertensive rats (SHRs) (WKY: control=0.3±0.01, 10−7 M insulin=0.6±0.01; 10−7 M PD128907+10−7 M
cells. Methods: The primary cultured VSMC cells were treated by norepinephrine (NE) with or without the presence of D3 receptor agonist, PD128907. The proliferation of VSMC cells was determined by [3H]-TdR incorporation. Result: NE dose-dependently increased proliferation of primary cultured VSMC cells from aorta of Sprague–Dawley rats, this effect was via α-adrenergic receptor, because α-adrenergic receptor blocker, phentolamine, blocked the stimulatory effect of NE on VSMC proliferation. D3 receptor agonist, PD128907, by itself (10− 8 mol/L or 10− 7 mol/L) had no effect, but reduced the stimulatory effect of NE on VSMC proliferation [NE10− 6 mol/L=6315±245 cpm vs. NE10− 6 mol/L+ PD128907 10− 8 mol/L = 5047 ± 331 cpm, P < 0.05;NE10− 6 mol/L = 6315 ± 245 cpm vs. NE10− 6 mol/L + PD128907 10− 7mol/L = 4898± 286 cpm, P<0.05]. Conclusion: Activation of D3 receptor reduces the stimulatory effect of NE on VSMC proliferation, which may take part into the pathogenesis of essential hypertension. doi:10.1016/j.ijcard.2009.09.236 EX000456 Effect of ETB endothelin receptor on Na+–K+ ATPase activity in renal proximal tubule cells and its mechanisms YAN LIU, ZHEN LI, DUOFEN HE, WEIBIN SHI, JIAN YANG, CHANGQING YU, CHUNYU ZENG Daping Hospital, The Third Military Medical University, China
EX000458 Effects of D1-like dopamine receptor on insulin receptor-mediated proliferation of vascular smooth muscle cells YU HAN, JIAN YANG, HEFEI HUANG, WEIBIN SHI, CHUNJIANG FU, DUOFEN HE, CHUNYU ZENG Daping Hospital, The Third Military Medical University, China Objective: To investigate the role of D1-like dopamine receptor on insulin receptor-mediated proliferation of vascular smooth muscle cells. Methods: A10 cells were used in this study and the mechanisms of D1-like receptor on insulin receptor were determined by immunoblotting. The proliferation of VSMC cells was determined by [3H]-TdR incorporation. Results: Insulin increased proliferation of A10 cells in a concentration-dependent manner. D1-like receptor, by itself, had no effect on cell proliferation, but blocked the insulin-mediated proliferation of A10 cells. Immunoblotting results showed that activation of D1like receptor by fenoldopam inhibited the insulin receptor expression, which might take part in the inhibitory effect of D1-like receptor on insulin receptor-mediated cell proliferation. Conclusion: Activation of D1-like receptor inhibits insulin receptor-mediated proliferation of vascular smooth muscle cells, which might be involved into the pathogenesis of essential hypertension. doi:10.1016/j.ijcard.2009.09.239
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+
Objective: To determine the effect of ETB receptor on Na –K ATPase activity in renal proximal tubule cells and its mechanisms. Methods: Immortalized renal proximal tubule (RPT) cells from WKY (Wistar–Kyoto) rat were used in this study, Na+–K+ ATPase activity was measured by oubain method. Result: Activation of ETB receptor concentration- and time-dependently decreased Na+–K+ ATPase activity. The maximal effect was about 36.1% at 15 min. Pre-treatment with Ca2+ blocker nicardipine (10− 6 M/15 min), blocked the inhibitory effects of ETB receptor in WKY RPT cells; and the inhibitory effects of ETB receptor on Na+–K+ ATPase activity were lost in Ca2+-free medium. Conclusion: ETB receptor plays an important role in decreasing Na+–K+ ATPase activity, Ca2+ entry is involved in this signal pathway. doi:10.1016/j.ijcard.2009.09.237 EX000457 Effect of insulin on D5 dopamine receptor expression and function in renal proximal tubule cells JIAN YANG, YU HAN, HEFEI HUANG, DUOFEN HE, CHUNYU ZENG Daping Hospital, The Third Military Medical University, China Objective: To investigate the effect of insulin on D5 dopamine receptor expression and function in renal proximal tubule (RPT). Methods: Immortalized RPT cells and D5 receptor transfected HEK293 (HEK-D5) cells were used in the study to investigate the effect of insulin on D5 receptor expression and function, and those effects were compared in RPT cells from Wistar–Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs). The function of D5 receptor was determined by measurement of the Na+–K+-ATPase activity in HEK-D5 cells. Results: Insulin increased D5 receptor protein expression in a concentration- and time-dependent manner in WKY RTPT cells, but not in SHRs. The basal level of D5 receptor expression was higher in WKY cells than that in SHR cells. Stimulation with fenoldopam (D1-like dopamine receptor agonist) inhibited the Na+–K+ATPase activity; pretreatment with insulin increased the inhibitory effect of fenoldopam on Na+–K+-ATPase activity in HEK-D5 cells. Conclusions: The abberant regulation of insulin on D5 receptor expression and function might be involved in the pathogenesis of essential hypertension. doi:10.1016/j.ijcard.2009.09.238
S71
EX000459 Inhibitory effect of D3 dopamine receptors on insulin receptor expression and function in vascular smooth muscle cells H.F. HUANGa, Y. Hana, D.F. HEa, L.D. ASICOb, P.A. JOSEb, C.Y. ZENGa Department of Cardiology, Daping Hospital, The Third Military Medical University, China b Center for Molecular Physiology Research, Children':s National Medical Center and Department of Pediatrics, George Washington University School of Medicine and Health Sciences, USA
a
Vascular smooth muscle cell (VSMC) proliferation, which is central to development of vascular diseases, including hypertension, is regulated by numerous hormones and humoral factors. Activation of the insulin receptor stimulates the VSMC proliferation while dopamine receptors, via D1 and D3 receptors, inhibit the stimulatory effects of norepinephrine on VSMC proliferation (Am J Physiol Heart Circ Physiol. 2008; 294: H2761–8). We hypothesize that there is an interaction between D3 dopamine and insulin receptors in VSMCs; stimulation of D3 receptor inhibits insulin receptor expression and function. We found that stimulation of the D3 dopamine receptor inhibited the insulin receptor expression in a concentration- and time-dependent manner in rat aortic A10 cells, an embryonic thoracic aortic smooth muscle cells from normotensive Berlin-Druckrey IX. The inhibitory effect was evident at 10− 7 M, noted as early as 2 h and maintained for at least 30 h. The inhibitory effect of D3 receptor on VSMC proliferation was blocked by PKA inhibitor (PKA inhibitor 14–22, 10− 6 M), indicating that PKA is involved into the signal pathway. There is a physiological significance of the interaction between D3 receptor and insulin receptors because the D3 receptor agonist, PD128907, by itself had no effect on VSMC proliferation, but reduced the stimulatory effect of insulin VSMC proliferation, determined by MTT assay (control = 0.3 ± 0.004, 10 − 7 M insulin = 0.6 ± 0.007; 10 − 7 M PD128907 + 10− 7 M insulin = 0.4 ± 0.01, P < 0.05, n = 9). The inhibitory effect of D3 receptor on insulin receptor expression and function also occurred in primary cultured VSMCs from Wistar– Kyoto rats and spontaneously hypertensive rats (SHRs) (WKY: control=0.3±0.01, 10−7 M insulin=0.6±0.01; 10−7 M PD128907+10−7 M