Using biotelemetry several physiological parameters, such as heart rate, body temperature and ECG can be measured simultaneously in non-restrained, freely moving animals. The transmitter is placed in the peritoneal cavity through a ventral laparatomy. The weight of the transmitter without leads (about 3 g) is quite high for a mouse weighing 25 g. Also the volume of the implant (1.6 ml) has to be taken into account. Rough observation of transmitter implanted mice during experiments does not reveal abnormal behaviour. The aim of this study was to assess in an objective way the behaviour of mice carrying an intraperitoneal transmitter. Using an automated Laboratory Animal Behaviour Observation Registration and Analysis System (LABORAS) several behavioural parameters were monitored, such as eating, drinking, climbing, locomotion, grooming and resting without disturbing the animal. In this study male BALB/c (n=18) and 129-SV (n=18) mice were used in three different treatment groups: control animals (n=6), sham operated animals (n=6) and transmitter implanted animals (n=6).

After one week acclimatization to a shifted light/dark schedule with a 30 minute dimming period the animals were treated in cohorts according to a random block design. After operation the animals were placed back in the their home cage, placed by half on a heating pad for 24 hours and received buprenorphin (Temgesic7) as an analgetic for two days twice a day. In addition to standard food pellets and water, the operated animals received Solid Drink7 for four days, moistened food pellets and water containing 10% glucose for seven days. Behaviour of each animal was measured on LABORAS twice a week for one hour after the start of the dark/dimming period in the first week and for four hours in the second week. Body weight was determined each day. At the end of the experiment animals were killed and post mortem macroscopic inspection was carried out. Results of this study will be discussed.