The Involvement of Ser1898 of the Human L-Type Calcium Channel in Evoked Secretion
Figure 2
Amperometry measurements of catecholamine release in bovine chromaffin cells. (a) Traces of amperometry currents elicited in noninfected chromaffin cells by a 10 sec puff of 60 mM KCl (K60) as indicated by the arrow (left), and in the presence of 5 μM nifedipine (inset). The cumulative number of events per cell (), averaged with and without 5 μM nifedipine, was plotted versus time (right). An expanded view of the initial cumulative spike counts (lower, left) and the initial rate of secretion calculated from the linearization of the cumulative averaged spike count (0.53 ± 0.02 spike/sec; lower, right). (b) Traces of amperometry currents elicited by a 10 sec puff of 60 mM KCl (K60) in cells infected with pSFV containing GFP (left) and in the presence of 5 μM nifedipine (inset). The cumulative number of events per cell was averaged () with and without 5 μM nifedipine and plotted versus time (right). An expanded view of the initial cumulative spike counts (lower, left) and the initial rate of secretion calculated from the linearization of the cumulative averaged spike count (0.52 ± 0.01 spike/sec; lower, right). (c) Bovine chromaffin cells stimulated under the same experimental conditions as above in nominally Ca2+ free solution (left) or stimulated with isoosmotic solution containing 2 mM KCl a sham stimulation (right).
