Fig. 8

Examples of CSF-induced intracellular calcium transients in cultured hippocampal neurons. a Brightfield (transmitted light) image of cultured hippocampal neurons. b Fluorescent image of hippocampal neurons loaded with 5 μM Fluo-4 AM, in color-coded intensity scale (0–255, right) before the application of CSF. c An example of intracellular calcium peak response to CNS SLE CSF #4, 3 s after application. Scale bars for (a–c) are shown in lower right corner and cell bodies of neurons and astrocytes are indicated by arrows and asterisks, respectively. d–j Representative traces of intracellular calcium responses (normalized fluorescence intensity) of hippocampal neurons challenged by CSF from CNS SLE or NMO patients. CSF application is indicated by a black dot below the trace. CSF origin, dilution, as well as the presence/absence of external calcium is indicated above the traces. In an external solution with 2 mM Ca²⁺, 1:25 CNS SLE CSF #4 induced two types of responses, with (d) only fast or with (e) fast and late slow components. f The same sample at 1:50 dilution was also able to increase the cytosolic calcium concentration in the repeated application, to the same level as the first response. g 1:10 CNS SLE CSF #2 induced a fast calcium transient in 2 mM Ca²⁺. h Disease control NMO CSF in 1:10 dilution did not influence the intracellular calcium concentration in 2 mM Ca²⁺ external solution. i In a Ca²⁺-free external solution, 1:25 CNS SLE CSF #4 did not induce the fast transient, and j no calcium response could be detected after application of 1:10 CNS SLE CSF #2. Note: Calibration for (d–j) is shown in the lower right corner