Repeated toluene and cyclohexane inhalation produces differential effects on HPA and HPT axes in adolescent male rats

Neurotoxicology. 2023 Nov 7:S0161-813X(23)00142-0. doi: 10.1016/j.neuro.2023.11.003. Online ahead of print.ABSTRACTMisused volatile solvents typically contain toluene (TOL) as the main psychoactive ingredient. Cyclohexane (CHX) can also be present and is considered a safer alternative. Solvent misuse often occurs at early stages of life, leading to permanent neurobehavioral impairment and growth retardation. However, a comprehensive examination of the effects of TOL and CHX on stress regulation and energy balance is lacking. Here, we compared the effect of a binge-pattern exposure to TOL or CHX (4,000 or 8,000 ppm) on body weight, food intake, the hypothalamus-pituitary-adrenal (HPA) and hypothalamus-pituitary-thyroid (HPT) axes in male adolescent Wistar rats. At 8,000 ppm, TOL decreased body weight gain without affecting food intake. In addition, TOL and CHX altered the HPA and HPT axes' function in a solvent- and concentration-dependent manner. The highest TOL concentration produced HPA axis hyperactivation in animals not subjected to stress, which was evidenced by increased corticotropin-releasing-factor (CRF) release from the median eminence (ME), elevated adrenocorticotropin hormone (ACTH) and corticosterone serum levels, and decreased CRF mRNA levels in the hypothalamic paraventricular nucleus (PVN). TOL (8,000 ppm) also increased triiodothyronine (T3) serum levels, decreased pro-thyrotropin-releasing-hormone (pro-TRH) mRNA transcription in the PVN, pro-TRH content in t...

Source: Neurotoxicology - November 9, 2023 Category: Neurology Authors: P Soberanes-Ch ávez P de Gortari C Garc ía-Luna S L Cruz Source Type: research