title: The release of labelled acetylcholine and choline from cerebral cortical slices stimulated electrically.
abstract: 1 In order to establish the origin of the increased efflux of radioactivity caused by electrical stimulation of cerebral cortical slices which had been incubated with [(3)H]-choline, labelled choline and acetylcholine (ACh) collected by superfusion were separated by gold precipitation.2 In the presence of physostigmine electrical stimulation (1 Hz, 10 min) increased the release of only [(3)H]-ACh which was greatly enhanced by the addition of atropine.3 Continuous stimulation in the presence of physostigmine resulted in an evoked release of [(3)H]-ACh which declined asymptotically. This evoked release appeared to follow first-order kinetics with a rate constant which remained stable over the course of prolonged stimulation.4 The rate constant for the evoked release of [(3)H]-ACh with 1 Hz stimulation was three times greater in the presence of physostigmine and atropine than in the presence of physostigmine alone, while the size of the store from which [(3)H]-ACh was released was nearly identical under these two conditions.5 In the absence of physostigmine and atropine, stimulation caused the appearance of only [(3)H]-choline in the samples.6 Reduction of [(3)H]-ACh stores before the application of physostigmine resulted in a reduced evoked release of total radioactivity, both in the absence or presence of physostigmine and atropine, and decreased the evoked release of [(3)H]-ACh without affecting the release of [(3)H]-choline.7 Results suggest that electrical stimulation of cortical slices which had been incubated with [(3)H]-choline causes the release of only [(3)H]-ACh, both in the presence or absence of an anticholinesterase. The evoked increase in the efflux of total radioactivity is therefore a good measure of the release of [(3)H]-ACh.
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002540:Cerebral Cortex / Q000378:metabolism* / Q000502:physiology; D002794:Choline / Q000378:metabolism*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004558:Electric Stimulation; D066298:In Vitro Techniques; D010830:Physostigmine / Q000494:pharmacology; D051381:Rats; D013997:Time Factors
chemical_list: D002800:Cholinesterase Inhibitors; D001285:Atropine; D010830:Physostigmine; D002794:Choline; D000109:Acetylcholine