Fig. 7.

At 37°C, the optimum FBS concentration for resting Em measurements ranged from 0% to 1.0%. Fibers were prepared and tested according to protocol 2. Changes in resting Em over time when the physiological solution had no FBS (A) or contained 0.2% FBS (B). Variations in the FBS dose-response on resting Em at 25°C (C) and 37°C (D). Microelectrodes were filled with 1 M K-acetate. Error bars represent the SE of six or seven fibers from three or four mice. *At all times, mean Em at 37°C was significantly different from mean Em at 25°C. §Mean Em was significantly different from the mean Em at 0.2% FBS. Using ANOVA and LSD, P < 0.05.