Figure 4

Ca ²⁺ -entry evoked by sphingosine (SPH) in primary cultures of FLSs from patients with RA. (a) Intracellular Ca²⁺ measurement showing the effect of external application of 20 μM SPH in the presence and absence of extracellular Ca²⁺. (b-d) Intracellular Ca²⁺ measurements showing responses to externally applied substances: (b) 20 μM SPH, (c) 100 μM adenosine triphosphate (ATP), and (d) 30 μM lysophosphatidylcholine (LPC). In paired experiments on the same 96-well plate, responses were compared after pre-treatment with anti-TRPM3 antibody (TM3E3) or TM3E3 preadsorbed to its antigenic peptide ("+pep."; control group). (a-d) All data points are N = 8 and representative of 3 (n) independent experiments.