Nicotinic cholinergic signaling in hippocampal astrocytes involves calcium-induced calcium release from intracellular stores

In this report we provide evidence that neuronal nicotinic acetylcholine re ceptors (nAChRs) are present on hippocampal astrocytes and their activation produces rapid currents and calcium transients. Our data indicate that the se responses obtained from astrocytes are primarily mediated by an AChR sub type that is functionally blocked by Lu-bungarotoxin (alpha Bgt) and contai ns the alpha7 subunit (alpha Bgt-AChRs). Furthermore, their action is unusu al in that they effectively increase intracellular free calcium concentrati ons by activating calcium-induced calcium release from intracellular stores , triggered by influx through the receptor channels. These results reveal a mechanism by which alpha Bgt-AChRs on astrocytes can efficiently modulate calcium signaling in the central nervous system in a manner distinct from t hat observed with these receptors on neurons.