Effects of Various Anions on the Electrical and Mechanical Activity of the Smooth Muscle of Guinea-pig Ureter

1. Effects of various anions on the electrical and mechanical activity of guineapig ureter was examined by means of the sucrose-gap method and a mechanoelectronic transducer simultaneously. 2. The membrane potential was sepolarized in SO4, NO3 and I solution and hyperpolarized in Br and SCN solution. 3. The amplitude of the spontaneous action potential was recreased in anion solutions expect I solution. Th ehalf duration of the action potential was porlonged in NO3 and Br solution but the change was not constant in SO4 solution. 4. The prequency of the spontaneous action potential was increased in NO3, I and SO4 solution initially but gradually decreased or abokished later. 5. The positive after-potential which was observed in normal solution was depressed in SO4, NO3 and Br solution. 6. The phasic contraction was potentiated in anion solutions except SO4 solution. The order of potentiation at 10 min exposure was SCN- > NO3- > I- > Br- > Cl- > SO4-.