Pharmacology as a subject depends largely on experiments conducted in laboratory animals. Experimental animals like rat, guinea pig, rabbit, etc. are used for the biological assay. For the teaching purposes to use isolated strip preparations from various organs, the laboratory animal species has to be sacrificed just for a piece of tissue. The present study was aimed to develop ex vivo model for pharmacological experimentation, which will mimic the actual laboratory condition without sacrificing the experimental animals. Dose response curve of acetylcholine alone and in presence of different concentrations of atropine was plotted using isolated chicken ileum, chicken duodenum, rat ileum, and rat duodenum and their EC(50) values were compared. The effect of atropine in terms of its type of antagonism was predicted based on Schild plot and pA(2) values were obtained. The chicken ileum and duodenum were also evaluated for four- and three-point bioassay, respectively. The results suggested that acetylcholine produced a dose-dependent increase in contraction in both chicken and rat ileum and duodenum preparation. The concentration response curve of acetylcholine in chicken ileum shifted toward left side of rat ileum with a higher EC(50) value. Atropine shifted the concentration response curve of acetylcholine toward right with a change in EC(50) value. Schild plots indicated that antagonism produced by atropine was found to be competitive in nature. The pA(2) values of atropine were found significantly high with isolated chicken ileum as compared to rat ileum preparation. It is concluded that isolated chicken ileum and duodenum preparation can be employed for routine experiments of pharmacology subject and the use of these isolated preparations is a novel approach for managing pharmacological experiments and importantly, without sacrificing the experimental animals.
Keywords: Chicken ileum; duodenum; four point bioassay; pA2 value; three point bioassay.