Background: Serotonin receptors can be divided into seven different families with various subtypes. The serotonin 1A (5-HT1A) receptor is one of the most abundant subtypes in animal brains. The expression of 5-HT1A receptors in the brain has been reported in various animals but has not been studied in horses. The 5-HT1A receptor functions related to emotions and behaviors, thus it is important to understand the functional effects and distribution of 5-HT1A receptors in horses to better understand horse behavior and its associated mechanism. Methods: Brain samples from seven different regions, which were the frontal, central, and posterior cerebral cortices, cerebellar cortex and medulla, thalamus, and hypothalamus, were collected from six horses. Western blot analysis was performed to validate the cross-reactivity of rabbit anti-5-HT1A receptor antibody in horse samples. Immunofluorescence was performed to evaluate the localization of 5-HT1A receptors in the brains. Results: The protein bands of 5-HT1A receptor appeared at approximately 50 kDa in the frontal, central, and posterior cerebral cortices, cerebellar cortex, thalamus, and hypothalamus. In contrast, no band was observed in the cerebellar medulla. Immunofluorescence analysis showed that the cytoplasm of neurons in the cerebral cortices, thalamus, and hypothalamus were immunostained for 5-HT1A receptors. In the cerebellar cortex, 5-HT1A was localized in the cytoplasm of Purkinje cells. Conclusions: In conclusion, the study suggests that 5-HT and 5-HT1A receptor systems may play important roles in the central nervous system of horses, based on the widespread distribution of the receptors in the horse brain.

Per capita nail-products use and airborne VOCs emission in four techniques of nail care (full coat coloring, UVgel polish, repair silk, and acrylic overlay) are estimated in this study. These assessments were carried out in a sealed test chamber using artificial hand and nails. A polish remover and a gel cleanser as cleanser and acrylic liquid as solvent were the most commonly used nail products in all 4 of the nail care techniques. Acetone, isopropyl alcohol, and methanol, which are major components of a polish remover, were commonly detected in all nail care techniques while acetone was detected the most. In addition to these airborne VOCs, a variety of other components such as ethyl acetate, cyclohexane, and toluene were identified in full coat coloring technique. In the process of UV-gel polish care technique, the main airborne VOCs were caused by solvents and were not involved in the curing process of UV gels (base gel and top gel) and gel bonder. In the case of repair silk nail care techniques, which generated the most VOCs, the total amount of VOCs detected was about 1,118.8 ± 359.6 mg/capita. Of the VOCs, butane (862.2 ± 283.9 mg/capita), which is contained in glue dryer, represented the largest share. In the process of acrylic overlay nail care technique, ethyl methacrylate (EMA), which is the basic element of acrylic, and highly toxic methyl methacrylate (MMA) were detected at 396.6 ± 42.3 mg/capita and 141.8 ± 8.2 mg/capita, respectively. The per capita data is very useful in designing a ventilation system for environmental improvement of a nail shop and setting a health care policy for nail artists and customers.