The study by F. Guharay and F. Sachs investigates stretch-activated single ion channels in tissue-cultured embryonic chick skeletal muscle. The membrane of these muscles contains an ionic channel that is activated by membrane stretch, distinct from nicotinic and Ca²⁺-activated K⁺ channels. The channel has a conductance of 70 pS, a linear current-voltage relationship between -50 and -140 mV, and a reversal potential of +30 mV. Kinetic analysis reveals that the channel has one open (O) and three closed (C) states, with only the rate constant governing the C₁-C₂ transition being stretch-sensitive. The rate constant k₁,₂ varies with the square of the tension, following the equation k₁,₂ = k₀ . e^(αT²), where α is a constant describing stretch sensitivity and T is the tension. Cytochalasin B treatment increases the stretch sensitivity of the channel. The probability of the channel being open is influenced by extracellular K⁺ concentration, increasing from 0.004 to 0.26 in 150 mm-K⁺ saline. The channel appears to gather force from a large area of membrane, likely through a cytochalasin-resistant cytoskeletal network. The study also examines the role of secondary messengers and the kinetic model of the stretch-activated channel, suggesting that the channel is a direct mechanical link between the membrane and the cytoskeleton. The findings have implications for understanding mechanoreceptors and osmoreceptors in various sensory systems.The study by F. Guharay and F. Sachs investigates stretch-activated single ion channels in tissue-cultured embryonic chick skeletal muscle. The membrane of these muscles contains an ionic channel that is activated by membrane stretch, distinct from nicotinic and Ca²⁺-activated K⁺ channels. The channel has a conductance of 70 pS, a linear current-voltage relationship between -50 and -140 mV, and a reversal potential of +30 mV. Kinetic analysis reveals that the channel has one open (O) and three closed (C) states, with only the rate constant governing the C₁-C₂ transition being stretch-sensitive. The rate constant k₁,₂ varies with the square of the tension, following the equation k₁,₂ = k₀ . e^(αT²), where α is a constant describing stretch sensitivity and T is the tension. Cytochalasin B treatment increases the stretch sensitivity of the channel. The probability of the channel being open is influenced by extracellular K⁺ concentration, increasing from 0.004 to 0.26 in 150 mm-K⁺ saline. The channel appears to gather force from a large area of membrane, likely through a cytochalasin-resistant cytoskeletal network. The study also examines the role of secondary messengers and the kinetic model of the stretch-activated channel, suggesting that the channel is a direct mechanical link between the membrane and the cytoskeleton. The findings have implications for understanding mechanoreceptors and osmoreceptors in various sensory systems.