The use of poly R-478 as a marker to determine gastric emptying and intestinal propulsive motility in suckling rats.

During our studies on gastrointestinal motility in suckling rats using 51Cr or 51Cr-EDTA as markers, we noticed that these markers--in contrast to studies in adult rats--"adhered" to the gastrointestinal wall of sucklings. We therefore decided to test the use of another non-absorbable marker Poly R-478 (an acetylated anthrapyridone chromophore linked to an polyamino-ethylene-sodium ethylene sulfonate copolymer backbone developed by the Dynapol Corporation (Palo Alto, CA). This new method has appeared to be useful.