Effect of calcium concentration on the transmural potential difference and the intensity of the short-circuit current in the small intestine of rat, chicken and hen

Abstract

The effect of calcium concentration on the Transmural Potential Difference and the Intensity of the Short-circuit Current in rat, chicken and laying hen small intestine has been studied in vitro both in the presence and absence of sodium.The results show that calcium, in the presence of sodium, produces an increase in potential and current intensity much greater in hen intestine than in chicken and rat.In the absence of sodium, the response of the potential as regards calcium concentration in hen intestine is parallel to the one obtained in the absence of sodium: a rise in the potential until it reaches a maximum value that corresponds to a calcium concentration of 10.8 mM in the medium, followed by a drop in the potential.However, rat intestine responds differently: the potential, negative at the serosal, becomes more and more positive with higher concentrations of calcium until it practically disappears.