New Role of D-Cycloserine: Shorten Adaptation Process and Extend Maintenance Time of Motion Sickness.

Introduction: The aim of the study was to investigate the role of D-cycloserine (DCS) in the adaptation process and maintenance of motion sickness (MS).

Methods: In experiment 1, 120 SD rats were used to study the promoting effect of DCS on the adaptation process of MS in rats. They were randomly divided into four groups, DCS-rotation (DCS-Rot), DCS-static, saline-rotation (Sal-Rot), and saline-static, and further divided into three subgroups according to the adaptation time (4 days, 7 days, and 10 days) in each group. After being given DCS (0.5 mg/kg) or 0.9% saline, they were rotated or kept static according to the group. Their fecal granules, total distance, and total activity of spontaneous activity were recorded and analyzed. In experiment 2, other 120 rats were used. The experimental grouping and specific experimental method were the same as experiment 1. According to the grouping of the adaptive maintenance duration, the animals of 14 days, 17 days, and 21 days groups were measured on the corresponding date of the changes in the animals' exploratory behavior.

Results: In experiment 1, the fecal granules, total distance, and total activity of spontaneous activity of Sal-Rot returned to the control level on 9 days, and the DCS-Rot group returned to the control level on 6 days, indicating that DCS could shorten the adaptation time of MS rats from 9 days to 6 days. In experiment 2, the Sal-Rot could not maintain the adaptive state after 14 days' absence from the seasickness environment. The fecal granules of DCS-Rot increased significantly, and total distance and total activity of spontaneous activity of DCS-Rot decreased significantly from 17 days. These illustrate that DCS can prolong the adaptive maintenance time from within 14 days to 17 days in MS rats.

Conclusion: 0.5 mg/kg DCS injected intraperitoneally can shorten the MS adaptation process and extend the maintenance time of adaptation of SD rats.