The intracellular pH and the buffer capacity of the heart

Abstract

The intracellular buffering (delta HCO3-/delta pH) in rats is lowest in skeletal muscle, intermediate in the diaphragm and highest in cardiac muscle. In the hypertrophic heart due to aortic constriction or to the Goldblatt mechanism the buffer value increases markedly during the first weeks, but returns to normal or even subnormal values during stable hypertrophy. There is an electrochemical disequilibrium for hydrogen ions caused by an active transport of ions across the cell membrane, which is possibly correlated to the myocardial activity.

Simultaneous intracellular and extracelular pH measurement in the heart by 19F NMR of 6‐fluoropyridoxol

“…The intracellular pH determined for hearts in this study is similar to that reported by many previous studies, with a typical range of 7.02-7.20 for normally perfused hearts assessed using a variety of techniques (21,22,25,(35)(36)(37). Most studies have examined intracellular acidosis since this is found to accompany ischemia and leads to loss of contractile force.…”

“…The relative signal intensity of the 6-FPOL peaks could be controlled by adjusting the volume of perfusate bathing the heart. Spectra acquired in 2 min routinely provided signal-to-noise ratios of -8 and - 35 for intracellular and extracellular signals, respectively, with linewidths on the order of 160 Hz and 120 Hz after a Additton of 6-FPOL Recovery For the group of eight hearts, pH was found to be highly consistent. The downfield (intracellular) signal occurred in the range of -10.43 to -10.69 ppm, indicating pH = 7.00-7.18 with mean pHi = 7.11 t 0.07 (2SD, n = 8 hearts).…”