Role of perinuclear mitochondria in the spatiotemporal dynamics of spontaneous Ca2+ waves in interstitial cells of Cajal-like cells of the rabbit urethra
Article first published online: 2 JUN 2010
© 2010 The Authors. British Journal of Pharmacology © 2010 The British Pharmacological Society
British Journal of Pharmacology
Volume 161, Issue 3, pages 680–694, October 2010
How to Cite
Hashiatni, H., Lang, R. J. and Suzuki, H. (2010), Role of perinuclear mitochondria in the spatiotemporal dynamics of spontaneous Ca2+ waves in interstitial cells of Cajal-like cells of the rabbit urethra. British Journal of Pharmacology, 161: 680–694. doi: 10.1111/j.1476-5381.2010.00902.x
- Issue published online: 3 SEP 2010
- Article first published online: 2 JUN 2010
- Received5 February 2010Revised5 May 2010Accepted9 May 2010
Vol. 162, Issue 8, 1894, Article first published online: 22 MAR 2011
- ICC-like cell;
- spontaneous Ca2+ wave;
- perinuclear mitochondria;
- endoplasmic reticulum;
- inhibition of glycolysis
BACKGROUND AND PURPOSE Although spontaneous Ca2+ waves in interstitial cells of Cajal (ICC)-like cells (ICC-LCs) primarily arise from endoplasmic reticulum (ER) Ca2+ release, the interactions among mitochondrial Ca2+ buffering, cellular energetics and ER Ca2+ release in determining the spatiotemporal dynamics of intracellular Ca2+ remain to be elucidated.
EXPERIMENTAL APPROACH Spontaneous Ca2+ transients in freshly isolated ICC-LCs of the rabbit urethra were visualized using fluo-4 Ca2+ imaging, while the intracellular distribution of mitochondria was viewed with MitoTracker Red.
KEY RESULTS Spontaneous Ca2+ waves invariably originated from the perinuclear region where clusters of mitochondria surround the nucleus. Perinuclear Ca2+ dynamics were characterized by a gradual rise in basal Ca2+ that preceded each regenerative Ca2+ transient. Caffeine evoked oscillatory Ca2+ waves originating from anywhere within ICC-LCs. Ryanodine or cyclopiazonic acid prevented Ca2+ wave generation with a rise in basal Ca2+, and subsequent caffeine evoked a single rudimentary Ca2+ transient. Inhibition of glycolysis with 2-deoxy-glucose or carbonyl cyanide 3-chlorophenylhydrazone, a mitochondrial protonophore, increased basal Ca2+ and abolished Ca2+ waves. However, caffeine still induced oscillatory Ca2+ transients. Mitochondrial Ca2+ uptake inhibition with RU360 attenuated Ca2+ wave amplitudes, while mitochondrial Ca2+ efflux inhibition with CGP37157 suppressed the initial Ca2+ rise to reduce Ca2+ wave frequency.
CONCLUSIONS AND IMPLICATIONS Perinuclear mitochondria in ICC-LCs play a dominant role in the spatial regulation of Ca2+ wave generation and may regulate ER Ca2+ release frequency by buffering Ca2+ within microdomains between both organelles. Glycolysis inhibition reduced mitochondrial Ca2+ buffering without critically disrupting ER function. Perinuclear mitochondria may function as sensors of intracellular metabolites.