Drug delivery in research on nonhuman animals in the laboratory is still challenging because it is usually invasive and stressful. Stress-free voluntary oral drug administration in water lacks precise control of dose and timing of substance ingestion. Voluntary oral consumption of corticosterone has been previously successfully applied in mice using oat flakes, but protocols for oral corticosterone administration in rats remain unavailable. This study assessed the effectiveness of voluntary oral administration to rats of a palatable piece of bread soaked with corticosterone that can be rapidly prepared and is reliably dose- and timing-controllable. After three familiarization days, all rats ate the bread within 120 seconds of presentation, irrespective of the presence or absence of corticosterone or vehicle. Corticosterone plasma levels remained at basal levels with consumption of vehicle-containing bread, and they were significantly increased with corticosterone-containing bread. Hence, the method enabled corticosterone bodily assimilation while avoiding stress, making it a possible alternative for invasive and stressful procedures. This article includes a methodological refinement that lessens unnecessary discomfort to laboratory animals and is potentially suitable for acute and chronic protocol studies.

在实验室中对非人类动物进行研究时，药物的递送仍然具有挑战性，因为它通常具有侵入性并且压力很大。水中无压力的自愿口服药物缺乏对剂量和物质摄入时间的精确控制。先前已经使用燕麦片成功地在小鼠中成功地自愿使用了皮质酮的口服，但是尚无用于大鼠口服皮质酮的方案。这项研究评估了自愿对老鼠口服一种可口的面包片，浸泡了皮质酮的效果，这种面包可以快速制备，并且剂量和时间可控，可靠。熟悉三天后，所有老鼠都在出现后的120秒内吃掉了面包，无论皮质酮或赋形剂是否存在。食用含载体的面包时，皮质酮血浆水平保持在基础水平，而含皮质酮的面包中血浆皮质醇血浆水平显着升高。因此，该方法在避免压力的同时使皮质类固醇能够同化，使其成为侵入性和压力性手术的替代方法。本文对方法进行了改进，可以减轻实验动物不必要的不​​适，并可能适用于急性和慢性方案研究。