Inward rectification in muscle fibres of the toad Bufo marinus.

Inward rectification of the resting potassium conductance was studied in skeletal muscle fibres of the toad Bufo marinus. This conductance was shown to be blocked by Ba and Cs and located both in the surface membrane and the membranes of the tubular system. Some differences were found between the properties of this conductance channel in Bufo marinus and those reported for various species of Rana. The possible adaptative value of these differences is pointed out.