Fig. 1. Morphology of striated muscle cells dissociated from Polyorchis penicillatus at different temperatures and their associated membrane currents. (A) Phase-contrast micrograph of muscle cells dissociated at 20–22 °C showing that cells lose muscle feet and round up. Arrow indicates one tear-shaped cell with a remnant of myofibres. (B) Phase-contrast micrograph of muscle cells dissociated at 30 °C showing a muscle cell with two pairs of feet and a patch-recording pipette attached. (C) Histogram to show that muscle cells dissociated with 1 mg ml^-1 Pronase at 30 °C retain their in situ morphology with 84.51±6.80 % of cells having two or more pairs of muscle feet (myofibres). Values are means ± S.E.M. (D) Voltage-clamp recording of total membrane currents from a cell dissociated at 20–22 °C showing that both inward and outward current amplitudes are low. The stimulus protocol was 25 ms test pulses, incrementing in 10 mV steps from -70 to +90 mV from a holding potential of -80 mV. (E) Voltage-clamp recording of total membrane currents from a cell dissociated at 30 °C showing increased amplitude of the currents. Stimulus protocol as for D.