Intracellular pH and sodium-proton exchange activity of lymphocytes in stroke-prone spontaneously hypertensive rats

1. At the age of 20 weeks, intracellular pH (pHi) of circulating lymphocytes suspended in HCO(3-)-free NaCl media was not significantly different between stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar-Kyoto rats (WKY). 2. The initial recovery rate of pHi in lymphocytes tended to be greater in SHRSP than in WKY after the addition of 60 mmol/L or 120 mmol/L of NaCl, but there was no statistically significant difference. 3. The H+ equivalent efflux rate, which was a true reflection of Na(+)-H(+) activity, was significantly greater in SHRSP than in WKY (P less than 0.05). The difference in H+ equivalent efflux rate was not due to the difference in cellular buffering power between the two groups (P greater than 0.05). An increased Na(+)-H(+) exchange activity may play a partial role in the pathogenesis of hypertension.