Fecal bulking in a frequently mated female rat

Abstract

One month into a study examining the effects of flupenthixol on sexual behavior and con-ditioned partner preference, we noticed that one female Long-Evans rat started to lose weight. The animal was one of forty 200–250 g Long-Evans rats housed in groups of four in wire-bottomed mesh cage. Each rat had free access to laboratory-rat pelleted feed and water. The animal room was maintained at 21 ± 2˚ C and 30–80% humidity on a reverse 12:12-h light/dark cycle.Half the rats in the study received intra-peritoneal (i.p.) injections of 0.25 mg/kg every four days, 30 minutes before they engaged in sexual behavior. The other half received 1 ml/kg of 0.9% saline and served as a control group. The affected rat was in the flupenthixol treatment group, and the technician responsible for administering the IP injections reported the presence of a hard mass in the rat’s abdominal cavity. We examined the rat; palpation of the abdominal cavity indicated the presence of a firm fecal mass distending the colon. On neurologic examination the rat dis-played normal postural reactions, spinal reflexes, and nociception. Its gait, however, was slightly abnormal, but because flupen-thixol is a dopamine antagonist, we consid-ered the uncharacteristic movement to be a consequence of altered motor activity