PT - JOURNAL ARTICLE AU - S N Murphy AU - R J Miller TI - Two distinct quisqualate receptors regulate Ca2+ homeostasis in hippocampal neurons in vitro. DP - 1989 May 01 TA - Molecular Pharmacology PG - 671--680 VI - 35 IP - 5 4099 - http://molpharm.aspetjournals.org/content/35/5/671.short 4100 - http://molpharm.aspetjournals.org/content/35/5/671.full SO - Mol Pharmacol1989 May 01; 35 AB - Addition of quisqualate to mouse hippocampal neurons in vitro elicited two types of changes in [Ca2+]i as assessed by fura-2-based microfluorimetry. The first was a transient spike or group of oscillations and the second was a long lasting "plateau" response. The long-lasting response was abolished on removal of either Ca2+ or Na+ from the external medium or by blocking voltage-sensitive Ca2+ channels. Furthermore, the novel glutamate antagonist 6-nitro-7-cyano-quinoxaline-2,3-dione was a competitive inhibitor of this response. In contrast, none of these manipulations abolished the transient [Ca2+]i spike. Transient [Ca2+]i spikes or oscillations could also be produced by the alpha 1-adrenergic agonist phenylephrine. Production of such an alpha 1-response reduced the size of a subsequently elicited quisqualate response. However production of transient [Ca2+]i spikes with caffeine did not alter the size of the quisqualate-induced spike. We conclude that hippocampal neurons possess two different types of quisqualate receptors. The first mediates quisqualate-induced depolarization and the second mediates Ca2+ mobilization from intracellular stores.