Cardiovascular research
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Cardiovascular research · Feb 1995
Intracellular pH in vascular smooth muscle: regulation by sodium-hydrogen exchange and multiple sodium dependent HCO3- mechanisms.
The aim was to determine the mechanisms, particularly bicarbonate dependent mechanisms, of intracellular pH (pHi) recovery from various acidoses in vascular smooth muscle and to explore the ATP dependency of the respective mechanisms. ⋯ At least three transporters contribute to recovery from acidosis in vascular smooth muscle: Na+/H+ exchange, an Na(+)-HCO3- cotransporter which is sensitive to EIPA, and an Na+ dependent HCO3-/Cl- exchange sensitive to both SITS and EIPA. The Na(+)-HCO3- cotransporter appears to be similar to that described in human vascular smooth muscle. When the Na+/H+ exchanger is attenuated by cellular ATP depletion, the alternative pathways, particularly the Na(+)-HCO3- cotransporter, ensure that substantial pHi regulatory capacity is maintained.