Relaxant effects of mercury and mercury uptake in the smooth muscle of guinea-pig taenia coli

Abstract

1. 1. Hg 2+ (0.005-0.5 mM) induced a concentration-dependent reduction on high-K +-induced contraction of taenia coli. 2. 2. The K +-induced increase in 45Ca uptake was significantly reduced in the presence of Hg 2+ (0.05-0.5 mM). 3. 3. The contractions of the glycerinated taenia coli were inhibited by an increase in Hg 2+ concentration. 4. 4. Mercury uptake increased along the duration of Hg 2+ incubation. 5. 5. When muscles were rinsed with a medium containing 5 mM EDTA after 0.5 mM Hg 2+ treatment for 90 min about 30% of the original level of tissue mercury was retained. 6. 6. Possible mechanism for the tension inhibitory action of Hg 2+ include: (1) that Hg 2+ bound to cell membrane initially interferes with the permeability of Ca 2+ and that (2) the cellular mercury fraction that is not eliminated by EDTA subsequently correlates with the tension inhibitory action.