Effects of short-term toluene exposure on agonist binding to muscarinic acetylcholine receptors in rat brain

• Published in: Japanese Journal of Pharmacology 1997, Vol.73 (suppl.1), p.186-186
• Main Authors: Tsuga, Hirofumi, Honma, Takeshi
• Format: Article
• Language: English
• ISSN: 0021-5198; 1347-3506
• DOI: 10.1016/S0021-5198(19)45247-5

Toluene is one of the most widely used organic solvents in industry and is toxic to the central nervous system (CNS). To clarify the mechanisms of CNS toxicity following toluene inhalation, especially with respect to cholinergic neurons, changes in the binding affinity of the muscarinic acetylcholine receptor agonist carbamylcholine were determined in membranes isolated from the brains of rats exposed to toluene at concentration of 500-2000 ppm for 6 hours. Membrane fractions of frontal cortex, striatum and hippocampus were prepared and agonist binding affinities were determined by measuring the displacement of [^^3 H] N-methyl scopolamine binding activity by carbamylcholine. In frontal cortex, the number of high-affinity carbamylcholine binding sites was reduced following exposure to 1000 ppm or higher concentration of toluene. In striatum, this effect was less pronounced than in frontal cortex and was seen at only following exposure to 2000 ppm of toluene. On the other hand, in hippocampus, the high-affinity binding of carbamylcholine was increased following exposure to toluene. From these observations, we conclude that toluene exposure influences receptor/G protein coupling and that these effects are different in different regions of brain.