Fig. 5
Use-dependent reduction and recovery from inactivation of ICa.T modified by glycosylation inhibition with tunicamycin. a Time course for development of use-dependent reduction of ICa.T with or without tunicamycin (10−6 g/l) treatment for 24 h. ICa.T was recorded by a train of 28 pulses consisting of 100-ms duration at a test potential − 10 mV from the holding potential of − 100 mV with the stimulation frequency of 0.4, 2.5, or 4.0 Hz. The current amplitude of the first pulse of train stimulation was assigned as 1.0. b Time course of recovery from inactivation of ICa.T. Pulse protocol is shown in the inset. The current amplitude at the conditioning pulse (Ic) was assigned as 1.0, and the current amplitudes at the test pulse (It) were normalized to the ratio of Ic (It/Ic). Curves were fitted to the data using a double-exponential equation shown in the inset. c Time constants for the fast and slow components (Tfast, Tslow) and d their amplitudes in equation (Ampfast, Ampslow). The number of cells is indicated in parentheses. Values represent the mean ± SE. *p < 0.01 vs. vehicle