Electrical and pharmacological properties of the slow depolarization induced by Schaffer collateral stimulation in astrocytes of the rat hippocampal CA1 region.
Intracellular recordings were made from astrocytes of the hippocampal CA1 region in rat slice preparations. A single stimulus at the Schaffer collaterals with high intensities (>/=10 V), but not low intensities (<10 V), induced a slow depolarization similar to the evoked postsynaptic potentials observed in hippocampal CA1 neurons. The slow depolarization was almost abolished in the presence of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (20 microM) and N-methyl-D-aspartate receptor antagonist DL-2-amino-5-phosphonopentanoic acid (100 microM). Tetrodotoxin (0.5 microM) or Co(2+) (2 mM) also abolished this slow depolarization. The slow depolarization reversed its polarity at -8 mV in the presence of tetraethylammonium (20 mM). These results suggest that the synaptically released glutamate (Glu) induces depolarization, which is mainly mediated by ionotropic Glu receptors, in astrocytes in the hippocampal CA1 region.
Hattori
Gosuke
G
Department of Physiology, Kurume University School of Medicine, 67-Asahi-machi, Kurume 830-0011, Japan.
Tanaka
Eiichiro
E
Yokomizo
Yuji
Y
Shigemori
Minoru
M
Higashi
Hideho
H
D015763:2-Amino-5-phosphonovalerate / Q000031:analogs & derivatives* / Q000494:pharmacology; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000344:Afferent Pathways / Q000502:physiology*; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors; D001253:Astrocytes / Q000187:drug effects* / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D003035:Cobalt / Q000494:pharmacology; D004558:Electric Stimulation / Q000379:methods*; D004594:Electrophysiology / Q000379:methods; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D026941:Sodium Channel Blockers; D019789:Tetraethylammonium / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
D002121:Calcium Channel Blockers; D018691:Excitatory Amino Acid Antagonists; D026902:Potassium Channel Blockers; D026941:Sodium Channel Blockers; C096637:2-amino-5-phosphono-3-pentenoic acid; C011274:3-hydroxyaspartic acid; D001224:Aspartic Acid; D003035:Cobalt; D013779:Tetrodotoxin; D019789:Tetraethylammonium; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D015763:2-Amino-5-phosphonovalerate