Figure 5.

Effects of cold shocks on the V_m of SEs pretreated with the membrane-permeant cytoskeleton disruptor LatA. A and B, Time courses of three typical electrical responses triggered by cold shocks (ΔT) recorded from SEs preincubated in 500 nm LatA for 2 h (n = 12; A) or in a mixture of 500 nm LatA and 1 mm La³⁺ for 2 h (n = 14; B). The time courses of cold shocks (top graphs) were recorded by a thermocouple, and electrical responses (bottom graphs) were recorded by voltage-sensitive microelectrodes. C to E, Relationships between cold shocks, expressed as the ΔT applied to SEs pretreated with LatA (C, 250 nm, 1–1.5 h, and 500 nm, 2 h; D and E, 500 nm) and LatA/La³⁺ (D, 500 nm/1 mm, 2 h) and ΔV₁ (C and D) and ΔV₂ (E). Data points for La³⁺ in D and E were taken from Figure 4, E and F. F, Relationship between the entire signal length and the peak of the second voltage gradient (ΔV₂) after cold shock observed with SEs pretreated with 500 nm LatA (black circles) and 500 nm LatA/1 mm La³⁺ (crosses). La³⁺ controls (white circles) were taken from Figure 4G. G, Correlation between voltage transients ΔV₂ and ΔV₁ for SEs preincubated in 500 nm LatA for 2 h. Control values (untreated SEs; white circles) were taken from Figure 4H.