Long-lasting enhancement of synaptic activity in dissociated cerebral neurons induced by brief exposure to Mg2+-free conditions.
The long-lasting enhancement of periodic clusters of spontaneous excitatory postsynaptic currents (SEPSCs) was examined in dissociated chick cerebral neurons that had been transiently exposed to Mg2+-free solution for 15 min. Since the enhancement was diminished by blockade of synaptic transmission, it clearly depended on synaptic activities. A specific antagonist of N-methyl-D-aspartate receptors (NMDARs) also inhibited the potentiations. Furthermore, the presence of inhibitors of protein and RNA synthesis in the Mg2+-free solution blocked the potentiation. In the potentiated neurons, the frequency of miniature excitatory postsynaptic currents (mEPSPs) increased. In addition, a diffusible molecule(s) that promoted the potentiation appeared to be involved in this phenomenon, since the conditioned medium of Mg2+-free treated neurons enhanced synaptic activity in other dish.
Kudoh
S N
SN
Department of Organic Materials, Osaka National Research Institute, Ikeda, Japan.
Matsuo
A
A
Kiyosue
K
K
Kasai
M
M
Taguchi
T
T
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D002478:Cells, Cultured; D002642:Chick Embryo / Q000166:cytology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004594:Electrophysiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000187:drug effects* / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors
D017077:Culture Media, Conditioned; D018691:Excitatory Amino Acid Antagonists; D009419:Nerve Tissue Proteins; D013779:Tetrodotoxin; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D008274:Magnesium