Fig. 4. Time course of the inward negative uncorrected short-circuit current (I_tot) measured over the split gill half-lamella of Carcinus maenas during application (bars) of basolateral colchicine (0.2 mmol l^-1) and cytochalasin D (5 µmol l^-1). The amplitudes of the current deflections, which are due to voltage pulses of 1 mV, are inversely proportional to the resistance between the tips of the voltage electrodes.