CHOLINERGIC MECHANISMS IN PLANARIA-TORVA

1. 1. In the tissue of Planaria, cholinesterase, cholineacetyltransferase and acetylcholine were demonstrated, which permits the assumption that cholinergic system is one of the mediator systems in turbellaria. 2. 2. Cholinesterases in Turbellaria possess properties which differ from cholinesterases in mammals: preparations which act as inhibitors of mammalian cholinesterases exert a different effect on their activity and they also behave differently if substrate concentration is increased. 3. 3. Diffuse cholinesterase activity, which may be due to weak binding of the enzyme to cell structures, creates conditions unfavourable for a reliable histochemical localization. 4. 4. Cytochemical localization of cholinesterases which split AThCh resembles the one in higher animals species. © 1979.