Effects of Toluene Exposure on Signal Transduction: Toluene Reduced the Signaling via Stimulation of Human Muscarinic Acetylcholine Receptor m2 Subtypes in CHO Cells

The Japanese Journal of Pharmacology

Takeshi Honma²  Hirofumi Tsuga²  Tatsuya Haga¹ 

[1] Department of Neurochemistry, Faculty of Medicine, University of Tokyo;Department of Health Effects Research, National Institute of Industrial Health

关键词: Adenylyl cyclase;    G protein;    [35S]GTPγS binding;    Muscarinic acetylcholine receptor m2 subtype;    Toluene;   

DOI  :  10.1254/jjp.89.282

学科分类：药理学

来源: Nihon Yakuri Gakkai Henshuubu / Japanese Pharmacological Society

【 摘 要 】

References(32)Cited-By(6)The organic solvent toluene is used widely in industry and is toxic to the central nervous system (CNS). To clarify the mechanisms of CNS toxicity following toluene exposure, especially with respect to the G protein-coupling of receptors, we determined the effects of toluene on the activation of Gi by stimulating human muscarinic acetylcholine receptor m2 subtypes (hm2 receptors) expressed in Chinese hamster ovary (CHO) cells. We first examined whether toluene affects the inhibition of adenylyl cyclase by Gi. The attenuation of forskolin-stimulated cAMP formation by the stimulation of hm2 receptors was reduced in a medium containing toluene. Next, we determined the effects of toluene on carbamylcholine-stimulated [35S]GTPγS binding using membrane fractions of CHO cells expressing hm2 receptors. Carbamylcholine-stimulated [35S]GTPγS binding activity was markedly reduced when assayed using reaction buffers containing toluene. However, carbamylcholine-stimulated [35S]GTPγS binding activity was essentially unchanged following pretreatment of the cells with a toluene-saturated medium prior to membrane isolation. Toluene pretreatment and the toluene itself did not alter the characteristics of the binding of carbamylcholine and [3H]N-methylscopolamine to hm2 receptors. On the contrary of the effect of toluene for [35S]GTPγS binding, the effect of toluene for attenuation of forskolin-stimulated cAMP formation by the stimulation of hm2 receptors was irreversible. These observations indicate that toluene acts as an inhibitor of the signal transduction via hm2 receptor stimulation in CHO cells, and at least two mechanisms exist in the inhibition mechanisms by toluene.

【 授权许可】

Unknown