Pentachlorophenol (PCP) inhibits ion transport in the isolated toad cornea.

1. Active chloride transport from the stroma to the epithelial surface (tear side) accounts for 80% of the amphibian cornea short-circuit current (SCC). 2. The effect of pentachlorophenol (PCP, a wood preservative) on the bioelectric parameters of the toad Caudiverbera caudiverbera isolated cornea was studied. 3. PCP applied to the epithelial surface in the concentration range 0.3-4.3 microM caused a dose-dependent inhibition of the PD and of the SCC in 7 corneas. This inhibition was irreversible at all concentrations after several washouts. The agent had no effect when applied to the endothelial surface. 4. In 4 experiments the inhibitory effect was partly reversed by the addition of 1 microM calcium ionophore A-23187 to the epithelial surface. 5. It is concluded that PCP is an inhibitor of corneal active chloride transport and that this structure shows greater sensitivity to this agent than other tissues.