Catecholamine levels in the brain of rats exposed by inhalation to benzalkonium chloride

Abstract

Objectives: 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. Material and 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/m 3 . 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. Conclusion: 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.

Toxic effect in the lungs of rats after inhalation exposure to benzalkonium chloride

“…In an inhalation study performed in mice, it was found that inhalation of BAC at higher concentrations induced deep lung effects and also lung inflammation [25]. In previous years we assessed toxic effects of BAC to the respiratory system and changes in the concentrations of catecholamines in the brain of rats exposed by inhalation to BAC aerosol [26,27]. The present study is an extension of our earlier works assessing the toxic effects of exposure to aerosol of BAC water solution in laboratory animals under conditions of repeated inhalation exposure.…”

“…In recent years, numerous works have been published describing the toxic activity of BAC in the in vitro and in vivo studies [1][2][3][4][5][6][7][8][9][10][11][12][13]. Scientific interest in BAC toxicity to the living organisms has resulted from a wide range of its use as a bactericide and preservative.…”

“…Scientific interest in BAC toxicity to the living organisms has resulted from a wide range of its use as a bactericide and preservative. It has been found that BAC used as a component of eye drops may adversely affect the different structures of the eye [1,2,5,[7][8][9][10]. The widespread use of BAC also involves utilization of its bactericidal activity in the treatment of teeth [14] and the development of new nanocomposite structures with a builtin BAC molecule [15].…”

Psychological Stress and Cancer

“…The stress response consists in releasing key peripheral mediators such as catecholamines and glucocorticoids the role of which in the pathophysiology of chronic stress is extraordinarily complex and controversial (4). Moreover, in cancer, catecholamines can enhance carcinogenic properties of prostate, ovary, breast and colon tumor cells (5), while glucocorticoids are immune-suppressive agents (6). It has been reported that the immune system plays an important role in the development of cancer (7)(8)(9).…”