ION CONTENT AND ION FLUXES IN SMOOTH MUSCLE CELLS OF LONGITUDINAL LAYER OF GUINEA-PIGS VAS DEFERENS

The intracellular K+, Cl- and Na+ concentrations in the vas deferens cells of the guinea-pig have been estimated from the total ion content, the sorbitol space and the dry wt/wet wt ratio. The exchange of K+, Cl- and Na+ was studied by following the uptake and the efflux of these ions with radioactive isotopes. The following steady state flux values have been calculated;mK, 2.8 p-moles x cm-2 x sec-1;mCl, 13.2 p-moles x cm-2 x sec-1 and mNa, 7.4 p-moles x cm-2 x sec-1. The values for the permeability constants calculated by the constant field assumptions from the ion fluxes are for PK 8.9×10-8 cm/sec;PCl 9.7×10-8 cm/sec and for PNa 2.1×10-8 cm/sec. The introduction of these values and of the concentrations in the Goldman equation give a resting potential of -30 mV. This value is only half of the value of the measured resting potential. One of the possible explanations for the discrepancy between the measured resting potential and the calculated one is that the resting potential of these smooth muscle cells is partly a diffusion potential and partly due to the operation of an electrogenic sodium pump. © 1969 Springer-Verlag.