e0595 AngiotensinII modulates ion pumps of smooth muscle cells derived from umbilical artery of human neonates with hypertensive family history

Objective To investigate sodium pump and calcium pump activities and mRNA expression level and the changes after AngiotensinII (AngII) treatment in human umbilical artery smooth muscle cells (HUASMCs) isolated from neonates with positive hypertensive family history (FH + ) or with negative hypertensive family history (FH - ). Methods Ion pump activities in cultured HUASMCs were detected by spectrophotography. The mRNA expression of sodium pump α 1 -subunit and plasma membrane Ca 2+ -ATPase isoform 1 (PMCA1) in FH + and FH - HUASMCs was measured by RT-PCR. Results Sodium pump, calcium pump activities in FH + HUASMCs were higher than those in FH - group (p 1 subunit and PMCA1 showed no difference between two groups. In FH - group, after 24-h treatment, AngII (1×10 −7  mol/L) elevated the activities of sodium pump (4.62±0.26 vs 3.52±0.33) and calcium pump (4.00±0.31 vs 3.01±0.32), and up-regulated sodium pump α 1 -subunit mRNA expression (0.946±0.099 vs 0.697±0.050, n=5, p −6  mol/L) suppressed the activities of sodium (2.47±0.27) and calcium pump (1.79±0.27), and down-regulated sodium pump mRNA expression (0.445±0.065). Whereas, in FH + groups, both concentration (10 −6 and 10 −7  mol/l) of AngII suppressed the activities of sodium pump (3.49±0.34, 2.21±0.23 vs 4.70±0.44) and calcium pump (2.85±0.31, 1.87±0.16 vs 4.27±0.48), but only AngII (10 −7  mol/l) down-regulated their mRNA expression (α 1 -subunit: 0.515±0.133 vs 0.885±0.097, PMCA 1 : 0.165±0.049 vs 0.397±0.046, n=5, p Conclusions The activity of sodium pump and calcium pump is increased in FH + HUASMCs. AngII inhibits both Na + and Ca 2+ ion pumps activities and mRNA expression in FH + HUASMCs, and may have biphasic effects on ion pump activities and mRNA expression in FH - hUASMCs.