Preliminary studies on transmural potential and intensity of the short-circuit current in intestine of Gobius maderensis.

The electrical difference (PD) and short-circuit current (Isc) across anterior intestine have been studied in vitro with solutions of different ionic composition in Gobius maderensis. 30 minutes after the beginning of the experiment a PD of about 2 mv negative serosa and an Isc of approximately 200 micro A/cm2 were recorded. Omission of sodium (Tris as substitute) from the luminal side or from both sides leads to an increment of 800% in PD more negative serosa together with an increase of 969% in Isc. In the absence of chloride (sulphate as substitute) the PD and Isc decreased and attained constant positive values. When the potassium was omitted from the luminal side or from both sides neither the P nor the Isc changed. These findings corroborate the assumption that active transport of chloride ions from mucosa to serosa is the major factor for transmural PD and account for the short-circuit current in the anterior intestine of Gobius maderensis.