Nitric oxide signals parallel fiber activity to Bergmann glial cells in the mouse cerebellar slice

Stimulation of parallel fibers in the cerebellar cortex triggers a transient calcium increase in Bergmann glial cells, a special form of astrocytes. Using patch-clamping and imaging techniques we have found that this form of neuron-gila interaction is mediated by nitric oxide (NO) since the response is blocked by the NO-synthase inhibitor Nω-nitro-L-arginine and mimicked by NO donors. None of the neurotransmitter receptors of Bergmann gila identified so far participates in or interferes with this signaling cascade. The NO-triggered increases in [Ca2+]i, as studied in Bergmann glial cells in the slice or in cultured astrocytes, are due to Ca2+ influx and not to release from cytoplasmic stores. Thus, NO released from parallel fibers serves as a signaling substance to the neighboring glial elements.