[Investigation and analysis of chloride channels distribution over the surface and T-tubule membranes of frog skeletal muscle].

Two types of muscle fibre integral currents (T1T and T2T) were recorded using narrow-tipped extracellular pipettes in isolated sartorius muscles of frog, Rana temporaria. T1T and T2T responses presumably were generated by currents originating in the muscle fibers sarcolemma (M-band region) or both sarcolemma and T-system (Z-line region), respectively, and differently responded to the selective blockade of C1C chloride channels with anthracene-9-carboxylic acid (9-AC). Eva- luation of the role of prolongation of T1T responses in generation of multiple peaks of the second phase (Na current) of T2T integral currents in muscle fibers are discussed.