Peripheral toxicity of hemicholinium-3 in mice.

1 The site (i.e. peripheral or central) of the toxicity produced by hemicholinium-3 in mice was investigated. 2 Hemicholinium-3 was measured fluorometrically and acetylcholine was determined by gas chromatography after intraventricular or intraperitoneal administration of hemicholinium-3. 3 Hemicholinium-3 was not detected in the brain nor were acetylcholine levels decreased in the brain after systemic administration. 4 The dose-response curve following intraventricular administration demonstrated that hemicholinium-3 was not as lethal after central administration as it was after peripheral administration. 5 Approximately 24% of a 75 microgram intraventricular dose of hemicholinium-3 was found in the periphery at death. 6 These results suggest that hemicholinium-3 manifests its toxicity primarily in the periphery.