Ameliorative Effect of Hesperidin Against Motion Sickness by Modulating Histamine and Histamine H1 Receptor Expression.

Motion sickness (MS) is the visceral discomfort caused due to contradicting visual and vestibular inputs to the brain leading to nausea and vomiting. Sensory conflict theory which proves histamine elevations as the primary reason for MS provides a path for an effective pharmaco-therapy. We aimed to evaluate the anti-MS effect of hesperidin (HSP) by modulating histamine and histamine receptor H1 (HRH1) expression. The inhibitory effect of HSP on histamine release was studied in KU812 cells treated with 10 µM calcium ionophore. The in vivo anti-MS effect of HSP was evaluated in Balb/c mice. Thirty six mice were divided into six groups namely, normal control (NC, no rotation), hesperidin at 80 mg/kg body weight control (HSP80, no rotation), motion sickness (MS, rotation induced), dimenhydrinate (Standard drug) at 20 mg/kg body weight + rotation (STD + MS), hesperidin at 40 mg/kg body weight + rotation (HSP40 + MS) and hesperidin at 80 mg/kg body weight + rotation (HSP80 + MS). Hypothalamus and brainstem samples were analysed for histamine levels and HRH1 expression by RT-PCR, Western blot and immunohistochemistry analysis. Calcium ionophore treated KU812 cells significantly increased histamine release when compared to control cells. Pre-treatment with HSP inhibited histamine, HRH1 mRNA and protein expression. Histamine, HRH1 mRNA and protein expression in hypothalamus and brainstem samples of MS group increased significantly when compared to the NC group. Pre-treatment with HSP significantly reduced histamine, HRH1 mRNA and protein expression. Thus, indicating that HSP has a potent anti- MS effect by decreasing the elevated levels of histamine, HRH1 mRNA and protein expression in hypothalamus and brainstem regions.