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Vip Modulates Intracellular Calcium Oscillations in Human Lymphoblasts
| Content Provider | Scilit |
|---|---|
| Author | Anton, Peter A. Shanahan, Fergus Sun, Xiao Ping Diehl, David Kodner, Anatoly Mayer, Emeran A. |
| Copyright Year | 1993 |
| Description | Journal: Immunopharmacology and Immunotoxicology |
| Abstract | Vasoactive intestinal polypeptide (VIP) has been shown to stimulate adenylate cyclase in a human lymphoblast cell line (MOLT 4). In the present study, we monitored fluorescence in cell suspensions and in single fura-2 loaded MOLT 4 lymphoblasts to determine if VIP modulates intracellular calcium concentrations ([Ca^{2+}$]_{i}$), and if this modulation is mediated by adenylate cyclase. The distribution of [Ca^{2+}$]_{i}$ in resting and stimulated cells was non-homogeneous, with gradients of high [Ca^{2+}$]_{i}$ present in the subplasmalemmal space. In a subset of cells (10-30% of all cells studied), [Ca^{2+}$]_{i}$ showed $La^{3+}$-sensitive, temporal changes in the form of [Ca^{2+}$]_{i}$ oscillations with a baseline [Ca^{2+}$]_{i}$ value of 115±10 nM, an oscillation amplitude of 150±18 nM and a mean period of 9.2±2s. The remaining non-oscillating cells showed a constant [Ca^{2+}$]_{i}$ level of 75±5 nM (n=65 cells from 4 experiments). In the subset of cells with spontaneous [Ca^{2+}$]_{i}$ oscillations, VIP dose-dependendy $(10^{-12}$ to $10^{-8}$M) increased the amplitude of oscillations but did not stimulate their frequency. The stimulatory effect of VIP was correlated with baseline [Ca^{2+}$]_{i}$ in these cells, was attenuated in the presence of $La^{3+}$ (25 μM), but was unaffected by cell depolarization (126 mM KC1). Dibutyryl cyclic AMP $(10^{-4}$ to $10^{-3}$ M) and forskolin $(10^{-4}$M) had no effect on [Ca^{2+}$]_{i}$ oscillations, or on [Ca^{2+}$]_{i}$ in cells without oscillations. In cell suspensions, baseline [Ca^{2+}$]_{i}$ was found to be 55. 1±11.2 nM (meanS.E.M., n=11); VIP, cyclic AMP analogues or forskolin had no significant effect on [Ca^{2+}$]_{i}$. These findings suggest that: a) VIP modulates the amplitude of [Ca^{2+}$]_{i}$ oscillations generated by a cytosolic $[Ca^{2+}$] oscillator in a subset of cells at a concentration of $10^{-12}$M, a thousand-fold below the $K_{D}$ for the VIP receptor; b) baseline $[Ca^{2+}$] values may be related to both the ability of cells to generate spontaneous $[Ca^{2+}$] oscillations and of oscillating cells to respond to VIP; c) due to the small number of responding cells, VIP-induced [Ca^{2+}$]_{i}$ changes are not detectable when studied in cell suspensions. |
| Related Links | https://www.tandfonline.com/doi/pdf/10.3109/08923979309035238 |
| Ending Page | 446 |
| Page Count | 18 |
| Starting Page | 429 |
| ISSN | 08923973 |
| e-ISSN | 15322513 |
| DOI | 10.3109/08923979309035238 |
| Journal | Immunopharmacology and Immunotoxicology |
| Issue Number | 4 |
| Volume Number | 15 |
| Language | English |
| Publisher | Informa UK Limited |
| Publisher Date | 1993-01-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: Immunopharmacology and Immunotoxicology Neurosciences Calcium Oscillation |
| Content Type | Text |
| Subject | Immunology and Allergy Toxicology Pharmacology Immunology |
