Takeda N, Hasegawa S, Morita M, Matsunaga T
Department of Otolaryngology, Osaka University Medical School, Japan.
Pharmacol Biochem Behav. 1993 Aug;45(4):817-21. doi: 10.1016/0091-3057(93)90126-e.
Mitchell et al. (1976, 1977) suggested that pica, eating of nonnutritive substances such as kaolin, is an illness-response behavior in rats. In the present study, we first confirmed their suggestion and then examined the effects of antiemetics on emetic-induced pica in rats. Intraperitoneal injection of apomorphine induced dose-dependent kaolin consumption. Pretreatment with domperidone inhibited apomorphine-induced kaolin intake. Oral administration of copper sulfate and intraperitoneal injection of cisplatin also induced dose-dependent kaolin consumption. Pretreatment with ondansetron inhibited cisplatin-induced kaolin intake. These findings suggest that pica in rats was induced through 1) dopamine D2 receptors in the chemoreceptor trigger zone, and 2) the stomach, partly via 5-HT3 receptors in the visceral afferents in the stomach wall. The present findings support the conclusion that pica in rats is analogous to vomiting in other species and suggest that pica in rats is mediated by the same mechanisms as vomiting in humans. Accordingly, we extended the utility of the animal model to pharmacological research of emesis with pica as an analogue to emesis.
米切尔等人（1976年、1977年）提出，异食癖，即食用高岭土等非营养物质，是大鼠的一种疾病反应行为。在本研究中，我们首先证实了他们的观点，然后研究了止吐药对大鼠催吐诱导的异食癖的影响。腹腔注射阿扑吗啡可诱导高岭土的消耗呈剂量依赖性。预先使用多潘立酮可抑制阿扑吗啡诱导的高岭土摄取。口服硫酸铜和腹腔注射顺铂也可诱导高岭土的消耗呈剂量依赖性。预先使用昂丹司琼可抑制顺铂诱导的高岭土摄取。这些发现表明，大鼠的异食癖是通过以下方式诱导的：1）化学感受触发区的多巴胺D2受体，以及2）胃，部分通过胃壁内脏传入神经中的5-HT3受体。目前的研究结果支持了大鼠异食癖与其他物种呕吐类似的结论，并表明大鼠异食癖是由与人类呕吐相同的机制介导的。因此，我们将该动物模型的应用扩展到以异食癖作为呕吐类似物的呕吐药理学研究中。
