Persistent, specific and dose-dependent effects of toluene exposure on dopamine D2 agonist binding in the rat caudate-putamen.
Exposure to toluene (40-320 ppm; 4 weeks, 6 h/day, 5 days/week), followed by a postexposure period of 29-40 days, decreased the wet weight of the caudate-putamen and of the subcortical limbic area (maximal effect of 10% attained at 80 ppm toluene) of the male rat. Furthermore, toluene exposure decreased the IC50 values (significant effects attained at 80 ppm), the KH, the KL, and the RH% values of dopamine on [3H]raclopride-binding in the caudate-putamen. Toluene exposure did not significantly affect either the body weights, the wet weights of the whole brain, the serum prolactin levels, the KD or the Bmax values of [3H]raclopride-binding in the caudate-putamen and the subcortical limbic area, or the IC50 values of dopamine at [3H]raclopride-binding sites in the subcortical limbic area. Exposure to xylene or styrene (80 and 40 ppm, respectively; 4 weeks, 6 h/day, 5 days/week), followed by a postexposure period of 26-32 days, had no effect on the parameters described above (prolactin levels were not analyzed). The present study indicates that long-term exposure to low concentrations of toluene (> or = 80 ppm), but not xylene (80 ppm) or styrene (40 ppm), leads to persistent increases in the affinity of dopamine D2 agonist binding in the rat caudate-putamen.
Hillefors-Berglund
M
M
Department of Neuroscience, Berzelius Laboratory, Karolinska Institutet, Stockholm, Sweden.
Liu
Y
Y
von Euler
G
G
D000375:Aging / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001667:Binding, Competitive; D001835:Body Weight / Q000187:drug effects; D002421:Caudate Nucleus / Q000187:drug effects* / Q000378:metabolism; D018492:Dopamine Antagonists / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009929:Organ Size / Q000187:drug effects; D011388:Prolactin / Q000097:blood; D011699:Putamen / Q000187:drug effects* / Q000378:metabolism; D020891:Raclopride; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000819:agonists* / Q000187:drug effects; D012457:Salicylamides / Q000378:metabolism*; D013343:Styrenes / Q000633:toxicity; D014050:Toluene / Q000633:toxicity*; D014992:Xylenes / Q000633:toxicity
D018492:Dopamine Antagonists; D017448:Receptors, Dopamine D2; D012457:Salicylamides; D013343:Styrenes; D014992:Xylenes; D014050:Toluene; D020891:Raclopride; D011388:Prolactin