Analysis of mercury ions binding to the smooth muscle of guinea-pig taenia coli.

Mercury uptake to taenia coli increased with an increase of the Hg2+ concentration (0.05-5 mmol/l). The Scatchard plots of mercury uptake showed that two qualitative Hg2+ binding sites (high and low affinity sites) exist in taenia coli. The Scatchard analysis of Hg2+ binding at 4 degrees C indicated a single class of binding site (high affinity binding site only). These results indicate that Hg2+ binds to high affinity binding sites of cell membrane and Hg2+ of low affinity binding sites may reflect intracellular accumulation in taenia coli.