Localised astroglial dysfunction disrupts high-frequency EEG rhythms.
We used cerebral cortex injections of fluorocitrate to determine if selective astrocytic disturbances affect the electroencephalogram (EEG). Rats were halothane-anaesthetized and 0.8 nmol of sodium fluorocitrate was injected into hindlimb (motor-sensory) cortex. Extra-dural EEG electrodes were implanted after which the anaesthesia was ceased. EEG was recorded at 1, 3, 5, 7, 24 and 48 hours. There was a broad-band reduction in frequencies in the EEG between 20 and 100 Hz commencing within 1 hour of injection and largely restricted to the side of injection and to frontal cortex, and maximal at 3 hours. Halothane had a suppressive effect on gamma power after citrate injection, but also prevented EEG suppression caused by fluorocitrate, consistent with the hypothesis that some of the action of fluorocitrate depended on gap-junctions. The findings are consistent with the hypothesis that primary astroglial dysfunction leads to reduced neuronal transmission and further supports gap-junctions as mediating fluorocitrate-induced astroglial effects.
Willoughby
J O
JO
Centre for Neuroscience and Department of Medicine, Flinders University and Medical Centre, Adelaide, Australia.
Mackenzie
L
L
Pope
K J
KJ
Broberg
M
M
Nilsson
M
M
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology*; D002951:Citrates / Q000008:administration & dosage; D004569:Electroencephalography / Q000187:drug effects / Q000379:methods*; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology; D008297:Male; D009044:Motor Cortex / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D002951:Citrates; C007744:fluorocitrate