Effects of Tianxiang capsule on neurotransmitters and hormone level in rats with motion sickness

Objective To investigate the effects of Tianxiang capsule on Neurotransmitters and Hormone Level of rats with motion sickness. Methods Male SD rats were randomly divided into six groups, including blank control group, model control group, positive drug control group, low-dose, mid-dose and high-dose Tianxiang capsule groups with the method of random digital table, and every group had 10 mice. Except the normal group, the rats in the other groups were intragastrically pre-administered for 1 hour, and the low, medium and high doses of Tianxiang capsule were 0.91, 1.82, 3.64 g/kg, the positive drug control group was given scopolamine 1 mg/kg, and then the rat motion sickness model was induced by a rotary stimulation device. After the modeling, the feces, urine, standing hair, trembling were immediately observed and recorded, and the halo response index of the rats was calculated. The blood from the heart puncture was taken and the vestibular nucleus were put on the ice. Then, the content of histamine (HIS) in the vestibular nucleus and plasma was detected by ELISA. The expression of plasma cortisol (Cort) and arginine vasopressin (AVP) were measured by radioimmunoassay. Results Compared with the model control group, the motion sickness index of rats with low, medium and high doses of Tianxiang capsule (6.56 ± 2.16, 6.10 ± 1.35, 4.46 ± 2.50 vs. 8.90 ± 2.61) significantly decreased (P<0.05 or P<0.01). The HIS content in the vestibular nucleus (12.70 ± 3.86 μg/L, 11.45 ± 1.57 μg/L, 10.02 ± 1.30 μg/L vs. 17.50 ± 4.82 μg/L) significantly decreased (P<0.05 or P<0.01). The plasma content of HIS (4.24 ± 1.75 μg/L vs. 7.69 ± 3.06 μg/L), Cort (286.90 ± 8.72 ng/ml vs. 329.26 ± 29.04 ng/ml) and AVP (16.54 ± 2.48 pg/ml vs. 22.35 ± 3.08 pg/ml) in the high doses of Tianxiang capsule significantly decreased (P<0.05 or P<0.01). Conclusions The Tianxiang capsule could effectively reduce the motion sickness index of rats with motion sicknes, which might be related to the down-regulation of HIS in Vestibule Nucleus and HIS, Cort and AVP in plasma. Key words: Motion sickness; Histamine; Cortisol; Arginine vasopressin; Tianxiang capsule; Rats