Stretch‐sensitive channels in developing muscle cells from a mouse cell line.

摘要: 1. Recordings of single-channel activity were made from cell-attached patches on mouse C2 muscle cells at morphologically identifiable stages myogenesis in vitro. We have identified Ca2(+)-permeable, cation-selective channels that are gated by applying suction to the patch electrode and changes membrane potential analysed properties as well channel expression during myogenesis. 2. Single-channel could be detected when was held steady negative potentials. With monovalent cations electrode, current-voltage (i-V) relations linear. The is permeable Li+, Na+, K+, Rb+ Cs+, but not strongly selective among judged measurements conductance reversal potential. 3. 110 mM either CaCl2 or BaCl2 only inward change carrier, slope conductances approximately 13 24 pS currents reversed +22 +17 mV, respectively. relative permeability Ca2+ K+ calculated constant-field equation PCa/PK = 4. Channel openings occurred bursts brief closings separated much longer closed periods. Closed-time histograms best fitted with three exponential components, while burst duration two reflecting short long records. 5. Applying recording potentials produced discrete current levels. Mean open probability depended linearly square applied pressure greater positive divalent indistinguishable spontaneous recorded 6. absence increasing e-fold per 38 mV depolarization. Analysis kinetics response showed depolarization reduced slowest component closed-time distribution. 7. lanthanide cation gadolinium (Gd) amplitude unitary a concentration-dependent manner. amplitudes both outward same extent suggesting block voltage-independent. Gd half-maximal inhibition 6 microM.(ABSTRACT TRUNCATED AT 400 WORDS)