Antidote administration in mice exposed to sarin resulted in brainwave stabilization without cognitive protection

Resurgence of sarin use in the Syrian conflict demonstrates that chemical weapons are a vivid threat. Like other organophosphate compounds, sarin inhibits acetylcholinesterase resulting in cholinergic crisis. The current antidote therapy includes atropine (a muscarinic cholinergic antagonist) + an oxime (e.g., pralidoxime) to reactivate the inhibited cholinesterases. Long-term sequelae reported in victims of the 1995 Tokyo subway sarin attack emphasize the need to improve neuroprotection and to delineate more precise biomarkers of intoxication severity. Previously, we proposed that brain oscillations could indicate exposure severity to a sublethal dose of a neurotoxic agent. In the present study, we evaluated the effects of atropine + pralidoxime in mice exposed to a sublethal dose of sarin (0.9 LD₅₀) on changes in short-term recovery, brainwaves and behavioral patterns. We demonstrated the benefits of the antidotes on alleviation of the sarin-induced encephalopathy, stabilization of brain oscillations, and attenuation of anhedonia behavior. Nevertheless, mice exhibited work memory impairments associated with the disruption of theta oscillations during the task, the disruption of sleep architecture and the anxiety-like behavior when exposed to the non-convulsive sarin dose. These outcomes were not mitigated by atropine + pralidoxime administration. Our findings suggest that the currently recommended antidote for sarin poisoning provides only partial neuroprotection. Despite stabilizing brain waves in resting state, current antidote is not effective in preventing long-term neurobehavioral complications.