The aim of the study was to investigate if human pleura from different anatomical locations presents electrophysiology differences. Specimens were stripped over the 2nd-5th rib (cranial), 8th-10th rib (caudal), and mediastinum during open surgery and were mounted between Ussing chambers. Amiloride and ouabain were added towards mesothelial surface and trans-mesothelial potential difference (PD) was measured after 1, 5, 10 and 20 min. Trans-membrane resistance (R) was calculated from Ohm's law. R increased after amiloride addition, for cranial (net increase of 0.40 Omega x cm(2)) and caudal (1.16 Omega x cm(2)) pleural pieces. Mediastinal pleura R remained unchanged (0.09 Omega x cm(2)). R increase was higher for caudal than cranial (P=0.029) or mediastinal tissues (P=0.002). R increased after ouabain addition for caudal (1.35 Omega x cm(2)) and cranial (0.56 Omega x cm(2)) pleural pieces. Mediastinal pleural tissue did not respond (0.20 Omega x cm(2)). Caudally located pleura responded greater than cranial (P=0.043) or mediastinal (P=0.003) pleural tissues. Human pleura shows electrophysiology differences according to the location within the pleural cavity. Surgeons may waste mediastinal pleura when needed but should leave intact caudal parietal pleura, which seems to be electrophysiologically the most important part of the pleural cavity.