The long term effects of toluene exposure during synaptogenesis and early adolescence on nicotinic acetylcholine receptors

• Main Authors: Yu-Chi Tang, 唐于琪
• Other Authors: Ming-Huan Chan
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/44570021325763361566

碩士 === 慈濟大學 === 藥理暨毒理學研究所 === 93 === Toluene, one of the industrial solvents, is also voluntarily inhaled as drug of abuse. Recently, toluene has been shown to block the nicotinic acetylcholine receptors. Nicotinic receptors play an important role in brain development during synaptogenesis and early adolescence. The purpose of this study is to examine whether toluene exposure during synaptogenesis and early adolesecence can alter the the functions of nicotinic receptors. Sprague-Dawley rats were treated with toluene (500 mg/kg, i.p.) or corn oil over postnatal day (PN) 4 to 9 or 25 to 31. The nicotine-induced hypothermia, hyperlocomotion, seizure activity and antinociception were measured on PN 30-70 and PN 36-70. The nicotine-induced antinociception, hypothermia, and seizures were less remarkable in both male and female rats exposed to toluene than control rats. Nicotine-induced hyperlocomotion was also reduced in toluene-exposed male rats, while leaving the female rats unaffected. The results from Western blots showed no changes in the levels of α4, α7 and β2 nicotinic receptors in toluene-exposed and control rats. The nicotine-induced behavioral responses were not affected by toluene exposure during early adolescence. Our data indicate that toluene exposure during synaptogenesis but not during early adolescence may lead long-term alterations in the functions of nicotinic acetylcholine receptors, whereas the levels of α4, α7 and β2 nicotinic acetylcholine receptors in striatum, behind cortex, frontal cortex, hippocampus and thalamus are unaffected. It suggests that synaptogenesis is more sensitive than early adolescence to toluene.