Fast network oscillations in the rat dentate gyrus in vitro.
The dentate gyrus is a prominent source of gamma frequency activity in the hippocampal formation in vivo. Here we show that transient epochs of gamma frequency network activity (67 +/- 12 Hz) can be generated in the dentate gyrus of rat hippocampal slices, following brief pressure ejections of a high-molarity potassium solution onto the molecular layer. Oscillatory activity remains synchronized over distances >300 microm and is accompanied by a modest rise in [K(+)](o). Gamma frequency oscillations were abolished by a GABA(A) receptor antagonist demonstrating their dependence on rhythmic inhibition. However, in many cases, higher frequency oscillations (>80 Hz) remained in the absence of synaptic transmission, thus demonstrating that nonsynaptic factors may underlie fast oscillatory activity.
Towers
Stephen K
SK
School of Biomedical Sciences, University of Leeds, Leeds LS2 9NQ, United Kingdom.
LeBeau
Fiona E N
FE
Gloveli
Tengis
T
Traub
Roger D
RD
Whittington
Miles A
MA
Buhl
Eberhard H
EH
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D018891:Dentate Gyrus / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009924:Organ Culture Techniques; D010507:Periodicity; D010721:Phosphinic Acids / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013779:Tetrodotoxin / Q000494:pharmacology
D000779:Anesthetics, Local; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D010721:Phosphinic Acids; D011412:Propanolamines; D011810:Quinoxalines; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; C085075:CGP 55845A; D013779:Tetrodotoxin; D015763:2-Amino-5-phosphonovalerate; D011188:Potassium; D001640:Bicuculline