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Contrasting Calcium Dependencies of SAPK and ERK Activations by Glutamate in Cultured Striatal Neurons
Author(s) -
Schwarzschild Michael A.,
Cole Rebecca L.,
Meyers Melissa A.,
Hyman Steven E.
Publication year - 1999
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1999.0722248.x
Subject(s) - mapk/erk pathway , glutamatergic , nmda receptor , microbiology and biotechnology , glutamate receptor , extracellular , protein kinase a , kinase , chemistry , biology , neuroscience , receptor , biochemistry
Stress‐activated protein kinase (SAPK) and extracellular signal‐regulated kinase (ERK), both members of the mitogen‐activated protein kinase (MAPK) family, may in some circumstances serve opposing functions with respect to cell survival. However, SAPK and ERK can also be coordinately activated in neurons in response to glutamate stimulation of NMDA receptors. To explore the mechanisms of these MAPK activations, we compared the ionic mechanisms mediating SAPK and ERK activations by glutamate. In primary cultures of striatal neurons, glutamatergic activation of ERK and one of its transcription factor targets, CREB, showed a calcium dependence typical of NMDA receptor‐mediated responses. In contrast, extracellular calcium was not required for glutamatergic, NMDA receptor‐mediated activation of SAPK and phosphorylation of its substrate, c‐Jun. Increasing extracellular calcium enhanced ERK activation but reversed SAPK activation, further distinguishing the calcium dependencies of these two NMDA receptor‐mediated effects. Finally, reducing extracellular sodium prevented the glutamatergic activation of SAPK but only partially blocked that of ERK. These contrasting ionic dependencies suggest a mechanism by which NMDA receptor activation may, under distinct conditions, differentially regulate neuronal MAPKs and their divergent functions.