Alerting Responses and Actions of Atropine and Cholinergic Drugs

Abstract

A survey of the literature on the action of acetylcholine (ACh), anticholinesterase drugs, and atropine suggests that these substances influence the neuronal mechanisms involved in the production of the diffuse desynchronization of the electrical activity of the brain, also known as the arousal, or activating, or alerting response.¹Bonnet and Bremer * observed that small amounts (0.2_γto 2_γ) of ACh chloride, in intracarotid injections, "awakened" the<i>encephale isolé</i>cat preparation. Wescoe and associates⁴reported that isofluorophate (diisopropyl fluorophosphate; DFP), a powerful anticholinesterase synthetic substance, diminishes the voltage and increases the frequency of the dog EEG activity, while atropine, on the contrary, raises the voltage and shifts the frequency to the slower side, thus counteracting the isofluorophate-induced changes. Funderburk and Case⁵showed that in cats and monkeys atropine induces EEG changes identical with those of natural sleep (high-voltage slow waves and bursts of 10 to 14