Intercellular connexin channels (gap junction channels) have long been thought to mediate
molecular signaling between cells, but the nature of the signaling has been unclear. This
study shows that connexin channels from native tissue have selective permeabilities,
partially based on pore diameter, that discriminate among cytoplasmic second messenger
molecules. Permeability was assessed by measurement of selective loss/retention of tracers
from liposomes containing reconstituted connexin channels. The tracers employed were …