The peritoneal mesothelium is a barrier to ion transport in peritoneal dialysis. In the present study, we investigated, by means of Ussing chamber experiments, the effect of adrenaline on the electrical transepithelial resistance (R(TE)) of isolated visceral sheep peritoneum. Peritoneal samples from the omentum of adult sheep were isolated within 30 minutes of the animal's death and were transferred to the laboratory in a cooled Krebs-Ringer bicarbonate solution (4 degrees C, pH 7.5) bubbled with 95% O2/5% CO2. A visceral peritoneal planar sheet was mounted in an Ussing-type chamber and adrenaline (10(-7) mol/L) was added to the apical and the basolateral side in turn. We measured R(TE) before and serially for 30 minutes after addition of the adrenaline. Because active ion transport is temperature-dependent, all experiments were performed at 37 degrees C. All results are presented as mean and standard error (x +/- SE) of 6 experiments. The control R(TE0 (before adrenaline) was 20.05 +/- 0.61 omega x cm2. Within 1 minute after the addition of adrenaline to the basolateral side of the membrane, R(TE) increased to 21.8 omega x cm2, a rate that thereafter progressively decayed, returning to the control value. Adrenaline action on the apical side of the membrane was similar, with a rapid rise of R(TE) to 22.5 omega x cm2 and a subsequent decrease (p < 0.05). Previous studies provide evidence for a clear association between R(TE) and active ion transport. The results of the present study indicate rapid action of adrenaline on the permeability of the visceral peritoneum.