A ROLE FOR IONS IN BARRIER RECOVERY AFTER ACUTE PERTURBATION

The epidermal cutaneous permeability barrier can be disrupted by treatment with topical solvents. Recent studies have shown that barrier recovery, measured by the recovery of transepidermal water loss towards normal, is inhibited by high extracellular Ca++ and K+, and accelerated by low extracellular concentrations of these ions. To examine the effects of Ca++ or K+ fluxes on barrier recovery, we tested the effects on transepidermal water loss recovery of agents that modify these fluxes. K+ channel agonists or blockers modified the inhibitory effects on barrier recovery induced by raised extracellular Ca++ and K+. In addition, Na+/K+ adenosine 5' triphosphatase inhibitors reversed the inhibitory effects of high extracellular Ca++ and K+. Our results suggest that barrier recovery requires both Ca++ and K+ fluxes and are consistent with the hypothesis that both verapamil or dihydropyridine-sensitive Ca++-permeable channels and Ca++ sensitive K+ channels participate in epidermal permeability barrier homeostasis.