Intracellular pH in platelets from spontaneously hypertensive rats and Wistar-Kyoto rats

Intracellular pH in platelets from spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY) was measured using a pH-sensitive fluorescent dye, 2',7'-bis(carboxyethyl)carboxyfluorescein tetraacetoxy methyl ester (BCECF). Intracellular pH in platelets was significantly higher in SHR than in WKY (7.12 +/- 0.04 versus 7.06 +/- 0.02, P less than 0.01; n = 10). There was a close correlation between intracellular pH and systolic blood pressure (r = 0.66, P less than 0.01). Addition to platelets of 1-(5-isoquinolinesulphonyl)-2-methylpiperazine (H-7), a specific inhibitor of protein kinase C, produced a significantly larger decrease in intracellular pH in SHR than in WKY (0.06 +/- 0.02 versus 0.03 +/- 0.00, P less than 0.01, n = 5). These results suggest that protein kinase C may play an important role in the increased intracellular pH in SHR.