Module 5: Figure chromaffin cell Ca2+ transients

Mitochondrial modulation of the shape of Ca2+ transients in adrenal chromaffin cells.

In response to a 500 ms depolarization (first arrow) to activate Ca2+ entry, there was a rapid increase in Ca2+ concentration that recovered rapidly to give a very sharp transient (first arrow). When this stimulus was repeated in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) to inhibit the mitochondria, the transient had a much smaller amplitude and a much longer recovery period. This experiment demonstrates how mitochondria accelerate the recovery phase by soaking up Ca2+. Reproduced from The Journal of Cell Biology, 1997, vol. 136, pp. 833–844 by copyright permission of The Rockefeller University Press; see Babcock et al. 1997.