14.5 Provocative motion elicits hypothermia and tail vasodilation in rats and shrews: A new index of motion sickness in pre-clinical studies? Sukonthar Ngampramuan (Research Center for Neuroscience and Institute of Molecular Bioscience, Mahidol University, Bangkok, Thailand), Matteo Cerri, Flavia Del Vecchio (Department of Biomedical and Motor Sciences, University of Bologna, Bologna, Italy), Amornrat Kamphee (Research Center for Neuroscience and Institute of Molecular Bioscience, Mahidol University, Bangkok, Thailand), John Rudd (School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China), Eugene Nalivaiko (School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia) Cardinal symptoms of motion sickness in humans include cold sweating, nausea and vomiting, and facial pallor; these indices cannot be employed in most laboratory animals. Few human studies also reported motion sickness-related hypothermia due to cutaneous vasodilation in the limbs. The aim of the present study was to investigate whether similar motion-induced hypothermic responses are present in rats and in musk shrews (an insectivore possessing vomiting reflex). Adult male Wistar rats were administered either antiemetic ondansetron (0.5 mg/kg s.c.) or vehicle, and 30 min later were subjected to provocative motion (rotation 0.5 Hz, 40 min) in their home cages; the experiment was repeated one week later using a crossover design (n= 7). Rotation provoked mild hypothermia (from 37.4 ± 0.1 to 35.6 ± 0.2 °C, p b 0.001) that was attenuated by ondansetron by 28% (p b 0.05). In another group of un-instrumented rats, we used infrared thermography and found that rotation induced a transient increase of tail temperature (from 22.9 ± 0.6 to 25.1 ±0.6 °C, p b 0.05) indicative of vasodilation; this rise preceded the fall in the core body temperature seen in the telemetered studies. Infrared thermography was also used to investigate skin temperature changes induced by motion (linear shaker, 1 Hz, 15 min) in shrews (n= 6). All animals exhibited episodes of retching and/or vomiting (latency 205 ± 38 s) that was preceded by a transient increase in tail temperature (from 24.0 ± 1.5 to 27.0 ± 2.2 °C, p b 0.05). A fall of interscapular temperature (from 38.4 ± 0.5 to 36.6 ± 0.4 °C, p b 0.001) was also seen during motion testing. Provocative motion induces hypothermia via mechanism involving dilatation of the vascular bed of the tail. The tail vasodilation that precedes retching/vomiting in Suncus murinus, and the tail vasodilation in rats could form the basis of a potential index of nausea in experimental animals. doi:10.1016/j.autneu.2013.08.024