The effects of external divalent cations on drug-receptor interaction were examined using guinea pig taenia. The effects of histamine on membrane potential of taenia in various solutions were also examined using the sucrose gap method. Ca2+ and Me2+ played an important role in the combination of histamine with its receptor. Sr2+, Mn2+ and Co2+ do not substitute for. Ca2+ and Me2+ in this intera...

Zn2+ can induce a conformational change of Band 3 with concomitant inhibition of its anion transport activity of human erythrocyte membrane vesicles only from the cytoplasmic side. The Zn2+ inhibition exhibits a dose-dependent manner with an apparent half maximal concentration of 50 microM ZnCl2 and can be reversed by 0.5 mM EDTA, but not by 1 mM dithiothreitol. The Zn2+ effect is specific and ...