Conditioned food aversion in Suncus murinus (house musk shrew) - a new model for the study of nausea in a species with an emetic reflex

The lack of a small animal model with an emetic reflex in which the relatio nship between conditioned food aversion and emesis could be investigated pr ompted a study of the insectivore, Suncus murinus (the house musk shrew). A novel food (either tuna or chicken cat food) was paired (C+) with a single exposure to either nicotine (4 mg/kg sc), motion (I Hz, 4 cm, 10 min) or l ithium chloride (100 mg/kg ip) or was paired (C -) with either saline or sh am exposure to motion. Nicotine and motion both induced emesis (retching/vo miting) but lithium chloride did not. All three treatments produced a condi tioned food aversion after a single pairing with consumption of C+ food. Wh en given a choice between the two foods, S. murinus given lithium chloride, motion exposure and nicotine consumed, respectively, only 25%, 23% and 1 % of their total intake from the C+ food. This study shows that a conditione d food aversion can be readily induced in S. murinus and that the induction of emesis can be uncoupled from food aversion. S. murinus provides a promi sing new model in which the relationship between emesis, nausea and conditi oned food aversion can be investigated. (C) 2001 Elsevier Science Inc. All rights reserved.