Changes in hippocampal and cortical EEG after intraventricular administration of cholinolytics in rabbit and cat.

Effects of central (intraventricular) and peripheral (intraperitoneal or intravemus) injections of muscarinic cholinolytics: atropine sulphate, atropine nitrate and scopolamine hydrobromide, on hippocampal and neocortical EEG were compared in rabbits and in cats. Both salts of atropine might produce epileptic, electrical activity in the neocortex and in the hippocampus when they were administered intraventricularly in doses of 600 microgramm or more (rabbits) and in doses of 50-100 microgramm (cats). Scopolamine hydrobromide injected via the same route in similar doses was mot effective. The data suggest that the epileptic symptoms evoked by atropine are probably due to an action on a neuronal substrate common to both species used and that the action is mediated not through cholinergic, muscarinic receptors.