Previous studies from our laboratory have shown that PGE2-mediated suppression of T cell proliferation could result from decreased mitogen-induced [Ca2+]i elevation. In the present study, we ascertained whether such an attenuation in [Ca2+]i elevation is a global response of the T cell population, or an attenuation in a portion of the cell population. We also evaluated the effect of PGE2 on [Ca2+]i oscillations in T cells. These studies were performed in Fura-2 loaded splenic-T cells of Sprague-Dawley (200-250g) rats by employing the Ca2+ imaging technique. We found that stimulation of T cells with Con A triggered [Ca2+]i oscillations in about 10-30% of the cells whether or not they were pretreated (2h) with PGE2. In T cells without the PGE2 pretreatment, the oscillations amplitude were in the range of 60-170 nM over the basal [Ca2+]i. The frequency of the oscillation was approximately 3 mHz. However, in PGE2 pretreated T cells, the Con A-responsive cell population showed an approximately 50-70% decrease in the oscillation amplitude. Because [Ca2+]i oscillations might be dependent on Ca2+ influx, we evaluated the effects of PGE2 on Ca2+ influx and its release from intracellular stores using Fura-2 microfluorometry. We found that PGE2 significantly inhibited Ca2+ influx but not the release. These data suggest that PGE2 mediated suppression of Ca2+i response is related to both altered Ca2+ influx and Ca2+i oscillatory behavior.
|Original language||English (US)|
|State||Published - Mar 20 1998|
ASJC Scopus subject areas
- Molecular Biology