Behavioral and neurochemical effects induced by subchronic combined exposure to toluene at 40 ppm and noise at 80 dB-A in rats.
We investigated whether exposure to noise, in addition to its well-known potentiating effect on toluene-induced ototoxicity, may also exacerbate behavioral disturbances and brain neurochemical alterations produced by subchronic exposure to low toluene concentration. To test this hypothesis, we evaluated whether subchronic combined exposure (16 weeks, 104 h per week) to noise at 80 dB-A and toluene at 40 ppm potentiates the recently reported neurotoxic effects of subchronic exposure to 40 ppm toluene. Locomotor and rearing activities, sensitization to narcosis induced by acute toluene at high concentration, and tyrosine and tryptophan hydroxylase activities in the caudate-putamen and hippocampus were investigated in both male and female rats. Our results confirm that subchronic exposure to 40 ppm toluene significantly decreases rearing activity and leads to a sensitization to toluene-induced narcosis, as evaluated by loss of righting reflex, but fails to demonstrate any adverse effect of noise, alone or in combination with toluene. Given that toluene has addictive properties, the lack of potentiating behavioral and neurochemical effect of noise is discussed with regards to a recent study that has shown that methamphetamine neurotoxicity is potentiated by exposure to loud noise.
Berenguer
Patrick
P
Université de Caen, UMR CNRS 6185, Centre CYCERON, BP 5229, Boulevard Henri Becquerel, 14074 Caen cedex, France.
Soulage
Christophe
C
Fautrel
Alain
A
Péquignot
Jean-Marc
JM
Abraini
Jacques H
JH
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology*; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D001923:Brain Chemistry / Q000187:drug effects*; D002421:Caudate Nucleus / Q000187:drug effects / Q000378:metabolism; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism; D004298:Dopamine / Q000096:biosynthesis; D005260:Female; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009622:Noise / Q000009:adverse effects*; D011699:Putamen / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000096:biosynthesis; D012997:Solvents; D014050:Toluene / Q000633:toxicity*; D014365:Tryptophan Hydroxylase / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D012997:Solvents; D012701:Serotonin; D014050:Toluene; D019392:Cytochrome P-450 CYP2E1; D014446:Tyrosine 3-Monooxygenase; D014365:Tryptophan Hydroxylase; D004298:Dopamine