A, time-dependent reduction of the relative permeability constant (k) of dye transfer after 15, 30 and 45 min exposures to H7, a non-specific inhibitor of serine/threonine protein kinases. B, recovery of cell-to-cell dye transfer after washing off H7. k was determined in control conditions (a), after exposure to H7 (1 mM for 1 h; b), and then 30 min after washing with control medium (c). Bars indicate k values (min−1) as means and s.e.m., with values of n above.