Extracellular ATP mobilizes intracellular Ca2+ in T51B rat liver epithelial cells: A study involving single cell measurements

Alton L. Boynton, Robert V. Cooney, Timothy D. Hill, Thomas Nilsson, Per Arkhammar, Per Olof Berggren

Research output: Contribution to journalArticle

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Abstract

T51B rat liver epithelial cells were stimulated with extracellular ATP. Changes in cytoplasmic free Ca2+ concentration ([Ca2*]i) were measured by fura-2 both in a large population of cells on coverslips in a cuvette and in single cells in a microscopic system. Extracellular ATP evoked a prompt increase in [Ca2+]i in both the presence and absence of extracellular Ca2+, although the effect was less pronounced in the latter case. These findings indicate that at least part of the [Ca2+]i increase is due to mobilization of intracellularly bound calcium. Stimulation with ATP did not mobilize the total pool of intracellular releasable Ca2+, as evidenced from experiments where subsequent addition of ionomycin evoked a pronounced increase in [Ca2+]i in the absence of extracellular Ca2+. The effect of ATP was maintained at room temperature but was markedly impaired in the absence of continuous stirring of the buffer solution. In the absence of stirring, ATP had to be increased to the millimolar range in order to evoke a pronounced effect. Single cell measurements revealed a heterogenous Ca2+ response to ATP, with some cells failing to respond with a detectable increase in [Ca2+]i. The actual increase in [Ca2+]i was not uniform throughout the cytoplasm, but seemed to start in one part of the cell. Even if part of the [Ca2+]i increase might be accounted for by ATP promoting the hydrolysis of phosphatidylinositol 4,5-bisphosphate and thereby a generation of InsP3 and diacylglycerol, there was no initiation of DNA synthesis under the present conditions. Hence, extracellular growth factors exert either a quantitative difference in second messenger production or additional stimulatory effects by activating intracellular signal pathways beyond these represented by [Ca2+]i and protein kinase C.

Original languageEnglish
Pages (from-to)245-255
Number of pages11
JournalExperimental Cell Research
Volume181
Issue number1
DOIs
StatePublished - Jan 1 1989
Externally publishedYes

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Adenosine Triphosphate
Epithelial Cells
Liver
Ionomycin
Diglycerides
Second Messenger Systems
Phosphatidylinositols
Protein Kinase C
Signal Transduction
Intercellular Signaling Peptides and Proteins
Buffers
Cytoplasm
Hydrolysis
Calcium
Temperature
DNA
Population

ASJC Scopus subject areas

  • Cell Biology

Cite this

Extracellular ATP mobilizes intracellular Ca2+ in T51B rat liver epithelial cells : A study involving single cell measurements. / Boynton, Alton L.; Cooney, Robert V.; Hill, Timothy D.; Nilsson, Thomas; Arkhammar, Per; Berggren, Per Olof.

In: Experimental Cell Research, Vol. 181, No. 1, 01.01.1989, p. 245-255.

Research output: Contribution to journalArticle

Boynton, Alton L. ; Cooney, Robert V. ; Hill, Timothy D. ; Nilsson, Thomas ; Arkhammar, Per ; Berggren, Per Olof. / Extracellular ATP mobilizes intracellular Ca2+ in T51B rat liver epithelial cells : A study involving single cell measurements. In: Experimental Cell Research. 1989 ; Vol. 181, No. 1. pp. 245-255.
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