These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Oscillations of intracellular calcium induced by vasopressin in individual fura-2-loaded mesangial cells. Frequency dependence on basal calcium concentration, agonist concentration, and temperature.
    Author: Hajjar RJ, Bonventre JV.
    Journal: J Biol Chem; 1991 Nov 15; 266(32):21589-94. PubMed ID: 1939188.
    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 degrees 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. Ca(2+)-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.
    [Abstract] [Full Text] [Related] [New Search]