fig. 6

Adenosine generated during synaptic activity may be one of the safety mechanisms preventing CSD ignition. A Epidurally applied selective A1-receptor antagonist, DPCPX (1 mM) induced irregularly spaced synchronized discharges, indicating that it sufficiently penetrated cortex. B DPCPX applied to the non-primed occipital cortex caused full-blown CSDs without stimulation in 4 out of 8 mice, whereas photic stimulation evoked a small-DC shift during which ongoing EEG activity (except large-amplitude synchronized discharges) was suppressed in 10 out of 116 photic stimulation periods (C). EEG recordings were obtained with extracranial electrodes. Magnified EEG shown at an expanded time scale in inset in B disclosed high-amplitude discharges just before CSDs, possibly corresponding the neuronal synchronization preceding CSD generation