Mechanisms of cytoplasmic calcium signalling in cerebellar bergmann glial cells

Abstract

Mechanisms underlying intracellular calcium signals in Bergmann glial cells evoked by various neurotransmitters were investigated in experiments on cerebellar slices acutely isolated from 30-day-old mice. [Ca2+] in values were measured by means of a Ca2+-sensitive fluorescent probe fura-2. Extracellular application of ATP (10–100 µM), histamine (10–100 µM), or noradrenaline (or adrenaline, 0.1–10.0 µM) caused a temporary increase in cytoplasmic Ca2+ concentrations. The effect persisted in Ca2+-free extracellular solution and was blocked with thapsigargin (500 nM) or a specific blocker of the inositol-1,4,5-trisphosphate-sensitive intracellular channels heparin. Based on the pharmacological analysis, we postulate the involvement of P2 purinoreceptors, α1-adrenoreceptors, and H1 histamine receptors in an agonist-activated increase in [Ca2+] in in Bergmann glia. Thus, ATP, monoamines, or histamine induce calcium signal generation in Bergmann glial cells via activation of Ca2+ release from the inositol-1,4,5-trisphosphate-sensitive internal stores.