The activation of calcium/calmodulin-dependent protein kinase II after glutamate or potassium stimulation in hippocampal slices.
Two forms of long-term potentiation (LTP), N-methyl-D-aspartate receptor (NMDAR) dependent and non-NMDAR dependent, have been reported in hippocampal CA1 and CA3, respectively. The present study examined the activation of CaM-kinase II (calcium/calmodulin-dependent protein kinase II) in CA1 and CA3 areas after glutamate or potassium stimulation. Rat hippocampal slices were preincubated with one of the drugs (EGTA, DL-APV, CNQX, AP3, nitrendipine, KN-62, staurosporin, and H-89) before they were stimulated with either glutamate/glycine (100 microM/1 microM) or KCl (60 mM). Hippocampal CA1 area and CA3 area were then dissected and CaM-kinase II activities were assayed in vitro. Glutamate and KCl stimulations enhanced the percentage of Ca(2+)-independent CaM-kinase II activity in CA1 area. This enhancement was suppressed by EGTA, DL-APV, CNQX, or KN-62, suggesting that the neuronal stimulation effect in CA1 area was mediating through NMDA receptors. Conversely, there was no significant enhancement of CaM-kinase II activity in the CA3 area after glutamate or KCl stimulation. Nevertheless, the percentage of calcium-independent CaM-kinase II activity in the CA3 area was suppressed by EGTA, nitrendipine, KN-62, staurosporin, or H-89, indicating that the activity of CaM-kinase II in the CA3 area was independent of NMDA receptor activation.
Tan
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SE
Department of Psychology, Kaohsiung Medical College, Taiwan, R.O.C.
Chen
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SS
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000187:drug effects*; D018698:Glutamic Acid / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018698:Glutamic Acid; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D011188:Potassium; D002118:Calcium