Laxatives are generally studied with techniques which utilize the whole animal (in vivo). However, suitably prepared isolated systems (in vitro) may help to understand some aspects of the laxative action. The animals used for these studies are generally rats, mice, guinea pigs and rabbits. The simplest in vivo test consists of isolating the animals in individual cages and observing the percent of animals who have liquid or solid feces 8 hours after a particular treatment. Statistical comparison of the mean values of total diarrheal episodes in control (animals receiving a suitable vehicle) and test groups is made, and the results can be expressed graphically (Fig. 32). Since the examination of feces (i.e. to distinguish between soft, semi-solid and solid feces) is subjective it is preferable that the person who carries out the inspection is different from the one who administers the drugs.
KeywordsBarium Sulfate Circular Muscle Ussing Chamber Rabbit Ileum Basic Research Study
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