[Activation of Na(+)-H+ antiporter gene expression during vascular smooth muscle proliferation and cardiac hypertrophy].
To clarify the role of Na(+)-H+ antiporter as a subcellular signal in cardiovascular system, we determined mRNA levels of the Na(+)-H+ antiporter in the vascular smooth muscles and pressure-overloaded hearts in rabbits. The expression of the Na(+)-H+ antiporter gene in rabbit aortas and hearts was much more prominent at embryonic and neonatal stages than in adults. The growth of C5, which is deficient in the Na(+)-H+ antiporter, was accelerated again when the activity was restored by transfecting cells with full-length cDNA for Na(+)-H+ antiporter in an expression vector. In pressure-overloaded hearts, the Na(+)-H+ antiporter mRNA was increased 2.5 fold of sham-operated rabbits at 3 days after aortic constriction, lasting for more than 2 weeks. We conclude from these results that activation of the Na(+)-H+ antiporter gene plays a key role in both cardiac hypertrophy and vascular smooth muscle cell proliferation.
Takewaki
S
S
Laboratory Medicine, University of Tokyo.
Nagai
R
R
D000818:Animals; D006332:Cardiomegaly / Q000235:genetics* / Q000503:physiopathology; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology; D002455:Cell Division; D005786:Gene Expression Regulation; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D011817:Rabbits; D017923:Sodium-Hydrogen Exchangers
D002352:Carrier Proteins; D012333:RNA, Messenger; D017923:Sodium-Hydrogen Exchangers