PMID: 11923408Mar 30, 2002Paper

Synaptically released acetylcholine evokes Ca2+ elevations in astrocytes in hippocampal slices

The Journal of Neuroscience : the Official Journal of the Society for Neuroscience
Alfonso AraqueW Buño

Abstract

Recent results have demonstrated the existence of bidirectional communication between glial cells and neurons. We investigated in brain slices whether rat hippocampal astrocytes respond to acetylcholine synaptically released by an extrinsic pathway. We stimulated the stratum oriens/alveus, which contains cholinergic afferents from the septum and diagonal band of Broca, and recorded whole-cell membrane currents and intracellular Ca2+ levels of astrocytes located in the hippocampal stratum oriens. Nerve-fiber stimulation evoked a long-lasting inward current and increased the Ca2+ levels in astrocytes. Both astrocytic responses were abolished by tetrodotoxin or Cd2+ and were increased by 4-aminopyridine, indicating that the responses were attributable to synaptically released neurotransmitter. The inward current was inhibited by glutamate transporter antagonists, indicating that it was attributable to the electrogenic glutamate transporter activity. The synaptically evoked intracellular Ca2+ elevations were not affected by glutamate receptor antagonists but were abolished by atropine, indicating that they were mediated by muscarinic cholinergic receptors. Thapsigargin prevented the Ca2+ elevation but did not modify the inward curr...Continue Reading

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