Abstract
1. The convulsive activity induced by catechol has been examined in anaesthetized mice either by determining the CD50 for the convulsions in drug-treated and control animals, or by studying the effects of various drugs on the total whole body activity. 2. The results indicate that catecholamines play no part in the mechanism of action of catechol. Drugs which alter cerebral catecholamine levels had no effect on the convulsions, nor did the alpha- and beta-adrenoceptor blocking drugs. 3. 5-Hydroxytryptamine (5-HT) could possibly be important, though results with drugs which either change brain 5-HT levels, or block 5-HT receptors were inconsistent. 4. gamma-Aminobutyric acid also appears not to be involved in the mechanism of action of catechol. 5. The results strongly suggest that catechol primarily activates a central cholinergic system, in that muscarinic and nicotinic receptor blocking drugs inhibit, and anticholinesterases potentiate the convulsions.