Catecholamine levels in the brain of rats exposed by inhalation to benzalkonium chloride.
OBJECTIVE
The aim of the study was to obtain quantitative data on the effect of inhalation exposure to benzalkonium chloride (BAC) on the concentration of catecholamines and their metabolites in selected brain structures. Additionally, concentration of corticosterone (CORT) in plasma was estimated.


METHODS
Wistar rats were subjected to a single (6-hour) or repeated (3 days, 6 h/day) exposure to BAC aerosol at ca. 30 mg/m3. The Waters integrated analytical system of HPLC was used to determine the plasma corticosterone. Qualitative and quantitative determinations of catecholamines and their metabolites: 3,4-dihydroxyphenylacetic (DOPAC) and homovanillic (HVA) acids were performed with the use of the Waters integrity HPLC.


RESULTS
The determinations have shown that in the BAC-exposed rats the plasma CORT concentration was several times higher than in the control rats. A significant increase of the concentration of dopamine (DA) (striatum and diencephalon) and noradrenaline (NA) (hippocampus and cerebellum) and a significant reduction of adrenaline (A) level (cortex, hippocampus, striatum and mesencephaloon) was found to occur in the brain of rats exposed to BAC compared to control. In the animals exposed to BAC, the concentration of DOPAC, a DA metabolite, was significantly reduced, but the change occurred mainly in the striatum. This resulted in a significant decrease of the DOPAC/DA and HVA/DA metabolic ratio in this structure.


CONCLUSIONS
It is assumed that the alterations in the concentration of catecholamines and their metabolites in the BAC-exposed rats were related to the unexpectedly strong and persistent activation of the hypothalamo-pituitary-adrenocortical (HPA) axis evidenced by the high plasma CORT concentration.
Swiercz
Radosław
R
Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Łódź, Poland. radek@imp.lodz.pl
Grzelińska
Zofia
Z
Gralewicz
Sławomir
S
Wasowicz
Wojciech
W
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000336:Aerosols; D000818:Animals; D001548:Benzalkonium Compounds / Q000633:toxicity*; D001921:Brain / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000378:metabolism; D003345:Corticosterone / Q000097:blood; D004298:Dopamine / Q000378:metabolism; D004837:Epinephrine / Q000378:metabolism; D005260:Female; D006719:Homovanillic Acid / Q000378:metabolism; D019570:Inhalation Exposure; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric
D000336:Aerosols; D001548:Benzalkonium Compounds; D015102:3,4-Dihydroxyphenylacetic Acid; D004298:Dopamine; D003345:Corticosterone; D009638:Norepinephrine; D006719:Homovanillic Acid; D004837:Epinephrine