Abstract
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 interaction.
None of divalent cations used were involved in the competitive antagonist-receptor interaction or in the irreversible antagonist-receptor interaction.
Histamine which induced membrane depolarization and increased tension in normal Locke Ringer solution had no effect on the membrane potential and tension in Mg2+-free Se2+-solution. The mechanism for this phenomenon has been discussed herein.
