Bilayers containing calcium ionophore A23187 form channels.

For the first time, based on bilayer membrane conductance experiments, it has been shown that A23187, a carboxylic calcium ionophore, incorporated in lipid bilayers gives single channel currents similar to the well known gramicidin channel. The current characteristics indicate the possibility that the transmembrane ion transport by this important calcium ionophore is initially by a carrier mechanism but with time is by a channel or pore mechanism due to the aggregation of the molecule in a lipid matrix.