Effects of surgery and analgesic administration on spontaneous behaviour in singly housed rats

The study examined the use of behaviour in assessing post-laparotomy pain i n rats given subcutaneous injections of saline (0.2 ml 100 g(-1)) or the an algesics buprenorphine (0.05 mg kg(-1)) or ketoprofen (5 mg kg(-1)). Proced ural control influences (handling/movement, anaesthesia, injections) were s tudied in a second group. Of 150 behaviours examined, discriminant analysis classified the main treatment effects, and class mean frequencies were com pared between treatments within each group. With the exception of buprenorp hine treatment, control procedures reduced the frequency of active, attenti ve and grooming behaviour, and increased sleeping during 24 hours following each treatment. Moving animals to the theatre was the main factor responsi ble for these changes. Surgery also reduced active and attentive behaviour. Animals given pre-operative saline were more frequently inactive than thos e given ketoprofen. These effects most likely resulted from post-surgery pa in, but this was not significantly diminished with the ketoprofen dose used . In all cases, buprenorphine outweighed these effects, causing a sustained increase in active, inactive and attentive behaviour, such that determinat ion of any analgesic effects was impossible. The study underlined a role fo r pain assessments based on rat behaviour. Drug-related effects emphasised a need for more comprehensive assessments encompassing procedural influence s, before behaviour changes that are potentially pain related may be determ ined accurately. (C) 2000 Harcourt Publishers Ltd.