The phospholipase C inhibitor U73122 increases cytosolic calcium in MDCK cells by activating calcium influx and releasing stored calcium

Chung Ren Jan, Chin Man Ho, Sheng Nan Wu, Ching Jiunn Tseng

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)

Abstract

The effects of the phospholipase C (PLC) inhibitor U73122 on intracellular calcium levels ([Ca2+](i)) were studied in MDCK cells. U73122 elevated [Ca2+](i) dose-dependently, Ca2+ influx contributed to 75% of 20 μM U73122-induced Ca2+ signals. U73122 pretreatment abolished the [Ca2+](i) transients evoked by ATP and bradykinin, suggesting that U73122 inhibited PLC. The Ca2+ signals among individual cells varied considerably. The internal Ca2+ source for the U73122 response was the endoplasmic reticulum (ER) since the response was abolished by thapsigargin. The depletion of the ER Ca2+ store triggered a La3+-sensitive capacitative Ca2+ entry. Independently of the internal release and capacitative Ca2 entry, U73122 directly evoked Ca2+ influx through a La3+-insensitive pathway. The U73122 response was augmented by pretreatment of carbonylcyanide m-chlorophynylhydrozone (CCCP), but not by Na+ removal, implicating that mitochondria contributed significantly in buffering the Ca2+ signal, and that efflux via Na+/Ca2+ exchange was insignificant.

Original languageEnglish
Pages (from-to)895-908
Number of pages14
JournalLife Sciences
Volume63
Issue number10
DOIs
Publication statusPublished - 1998 Jul 31

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Fingerprint Dive into the research topics of 'The phospholipase C inhibitor U73122 increases cytosolic calcium in MDCK cells by activating calcium influx and releasing stored calcium'. Together they form a unique fingerprint.

Cite this