title: Sustained dendritic gradients of Ca2+ induced by excitatory amino acids in CA1 hippocampal neurons.
abstract: Spatially resolved measurements of intracellular free calcium and of the changes produced by excitatory amino acids were made in neurons isolated from adult mammalian brain. Extremely long-lasting (minutes) Ca2+ gradients were induced in the apical dendrites of hippocampal CA1 neurons after brief (1 to 3 seconds), local application of either glutamate or N-methyl-D-aspartate (NMDA). These gradients reflect the continuous flux of Ca2+ into the dendrite. The sustained gradients, but not the immediate transient response to the agonists, were prevented by prior treatment with the protein kinase C inhibitor sphingosine. Expression of the long-lasting Ca2+ gradients generally required a priming or conditioning stimulus with the excitatory agonist. The findings demonstrate a coupling between NMDA receptor activation and long-lasting intracellular Ca2+ elevation that could contribute to certain use-dependent modifications of synaptic responses in hippocampal CA1 neurons.
mesh_terms: D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism*; D003712:Dendrites / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D006168:Guinea Pigs; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D016202:N-Methylaspartate; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D013110:Sphingosine / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D001572:Benzofurans; D005456:Fluorescent Dyes; D005971:Glutamates; D007473:Ion Channels; D001224:Aspartic Acid; D018698:Glutamic Acid; D013779:Tetrodotoxin; D005680:gamma-Aminobutyric Acid; D016202:N-Methylaspartate; D011493:Protein Kinase C; D008274:Magnesium; D013110:Sphingosine; D011188:Potassium; D002118:Calcium; D016257:Fura-2