Standardized Preparation of Isolated Rabbit Duodenal Smooth Muscle For In Vitro Pharmacological Assessment of Contractile Activity.

The coordinated contractile activity of gastrointestinal smooth muscle forms the physiological basis for maintaining normal digestion, absorption, and transport functions, with its dysfunction closely associated with motility disorders. The isolated organ perfusion technique eliminates complex in vivo interferences-such as neural, endocrine, and hemodynamic factors-serving as a classic model for pharmacological studies. To this end, this study details a stepwise protocol for the standardized preparation of rabbit isolated duodenal smooth muscle. The procedural workflow highlights the critical steps of preparing solutions, euthanizing the rabbit, performing a precise aseptic mid-abdominal laparotomy for rapid tissue excision, suspending the smooth muscle strips, and calibrating transducers for real-time tension recording. Based on this technical platform, we further validated the method by evaluating the effects of Huoxiang Zhengqi Oral Liquid (HXZQ-OL) on spontaneous contractions and acetylcholine/barium chloride-induced tetanic contractions. In conclusion, this protocol yields a robust and highly reproducible methodological framework, providing a broadly applicable in vitro screening platform for the pharmacological assessment of therapeutic agents targeting gastrointestinal motility.