Influence of Endogenous Cardiac Glycosides, Digoxin, and Marinobufagenin in the Physiology of Epithelial Cells

Figure 5

Participation of rho/ROCK in the signaling pathway that leads to GJIC and TER increase by treatment with endogenous casdiac steroids (ECS) digoxin and marinobufagenin. (a, b) Inhibition of Rho-associated protein kinase (ROCK) by pretreatment of MDCK monolayers with Y-27632 suppresses the enhancement of GJIC induced by marinobufagenin (MBGN) or digoxin (DGX). (a) Representative images of Lucifer Yellow injection trials of cells in monolayers treated with either digoxin or marinobufagenin alone or with pretreatment with Y-27632. (b) A bar chart comparing the average number of cells stained from a number of trials of each treatment as indicated in the base of bars. Simple, paired comparisons (Student’s t) where made as indicated by bars. ; . (c and d) Inhibition of Rho-associated protein kinase (ROCK) by pretreatment of MDCK monolayers with Y-27632 suppresses the increment of TER induced by marinobufagenin (c) or digoxin (d). (c, d) Relationship of TER versus time of the different treatment combinations indicated in the inset. Each dot represents the average ± SE value of TER (Ohms·cm²) of nine repeats of 3 independent assays. Simple, paired comparisons (Student’s t) were made between ECS alone or ECS plus Y27 at each time. ; ; .

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