Oscillations of intracellular calcium induced by vasopressin in individual fura-2-loaded mesangial cells: Frequency dependence on basal calcium concentration, agonist concentration, and temperature

Roger J. Hajjar, Joseph V. Bonventre

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Intracellular free calcium concentration ([Ca2+]i) was measured in fura-2-loaded single rat mesangial cells by dual wavelength spectrofluorometry. Stimulation with arginine vasopressin (AVP) caused an initial sharp rise of [Ca2+]i followed by repetitive spikes. The frequency of the oscillations was dependent on the concentration of AVP. At 0.1, 1.0, 10.0, and 100.0 nM AVP, the frequencies of oscillations were 0.17 ± 0.05 (n = 6), 0.32 ± 0.05 (n = 6), 0.49 ± 0.05 (n = 6), and 0.48 ± 0.05 min-1 (n = 5), respectively. Reduction in extracellular [Ca2+] reduced the frequency of AVP-induced oscillations but did not abolish the oscillations. The frequency of calcium oscillations, upon stimulation with 1.0 nM AVP, was directly correlated with the basal [Ca2+]i prior to stimulation. Oscillation frequency increased with increasing temperature. An Arrhenius plot between 24 and 37°C indicated a strong temperature dependency of the oscillations with a Q10 of 3.0. Protein kinase C stimulation by active phorbol esters inhibited AVP-induced calcium oscillations but not the initial [Ca2+] response to AVP. These observations are consistent with a model incorporating a feedback loop linking [Ca2+]i to the mechanism of [Ca2+]i increase. Ca2+-induced Ca2+ release may be involved, whereby inositol 1,4,5-trisphosphate (inositol 1,4,5-P3) formation releases Ca2+ from an inositol 1,4,5-P3-sensitive pool, with subsequent Ca2+ uptake and release from an inositol 1,4,5-P3-insensitive pool.

Original languageEnglish
Pages (from-to)21589-21594
Number of pages6
JournalJournal of Biological Chemistry
Volume266
Issue number32
StatePublished - 1991
Externally publishedYes

Fingerprint

Dive into the research topics of 'Oscillations of intracellular calcium induced by vasopressin in individual fura-2-loaded mesangial cells: Frequency dependence on basal calcium concentration, agonist concentration, and temperature'. Together they form a unique fingerprint.

Cite this