Interleukin-6 inhibits L-type calcium channel activity of cultured cerebellar granule neurons.

Our previous work has shown that interleukin-6 (IL-6) implements its neuroprotective effect by inhibiting the intracellular Ca(2+) overload in neurons. Here, we examined whether regulation of L-type calcium channels (LCCs) activities is involved in the neuroprotective action of IL-6. In cultured cerebellar granule neurons (CGNs), patch-clamp recording showed that the whole-cell Ca(2+) current and LCC current were significantly reduced by IL-6 pretreatment (120 ng/ml, for 24 h). Calcium imaging data indicated that IL-6 significantly suppressed high K(+)-induced intracellular Ca(2+) overload and LCC Ca(2+) influx. Moreover, expression of the LCC subunit, Ca(v)1.2, was remarkably downregulated by IL-6 in cultured CGNs. These findings suggest that IL-6 exerts a neurotrophic effect by preventing Ca(2+) overload, at least partly through inhibition of LCC activity in cultured CGNs.