1995/09/01 by John A. Trotter, Thomas J. Koob · 7 citations
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Seaweed-derived Bioactive Compounds #Skin and Cellular Biology Research #Cellular Mechanics and Interactions
paper · doi:10.1242/jeb.198.9.1951
Although previous investigations have shown that experimental increases and decreases of the concentration of extracellular Ca2+ produce correlated changes in the stiffness of holothurian dermis, they have failed to determine whether the Ca2+-correlated changes were due to Ca2+-dependent cellular events or to direct effects of Ca2+ on the viscosity of the extracellular matrix. We have addressed this question by testing two explicit predictions of the latter hypothesis: that dermal stiffness should be correlated with the Ca2+ concentration in the absence of viable cells; and that, in the presence of a normal extracellular Ca2+ concentration, drugs that inhibit cellular pathways dependent on Ca2+ should not affect dermal stiffness. Our results are inconsistent with the hypothesis and support the alternative hypothesis that Ca2+ is important only in the cellular regulation of dermal stiffness. In addition, we have extracted from dermal cells an organic factor that stiffens the extracellular matrix.