The Loose Patch Voltage Clamp Technique

Extracellular microelectrodes have been used for many years to apply focal electrical stimulation to individual cells (for example, see Pratt and Eisenberger [1919] and Huxley and Taylor [1958]). Strickholm (1961) was the first to use a single extracellular electrode for both voltage control and recording membrane current. Strickholm used this method (developed as part of his PhD thesis) to study muscle membrane impedance and capacitance. Strickholm’s method lay dormant for over 20 yr until it was revived by St�hmer and Almers (1982). Almers, St�hmer, and their collaborators used the loose patch-clamp to study a wide range of muscle sodium and potassium channel properties, including mobility, inactivation, and spatial distribution (St�hmer and Almers, 1982; Almers et al., 1983a,b, 1984; St�hmer et al., 1983; Roberts and Almers, 1984,1992; Weiss et al., 1986; Roberts, 1987).