Histogram showing the effect, in anaesthetised rats, of increasing surgical interference and analgesic on the post operative water intake during the dark hours

Liles and Flecknell (1993a)

Skin - making a 4 cm incision in the skin only of the abdomen followed by closing with stitches and staples.

Laparotomy - 4 cm incision in the skin as above plus 4 cm incision of the muscle so that the viscera were exposed followed by suturing of muscle layers and skin.

Lap + visc - Surgical procedure as above for Laparotomy plus gentle manipulation of the abdominal viscera.

Saline - given a single 0.5 ml subcutaneous injection of saline before removed from operating table.

Buprenorphine - 0.05mg Buprenorphine per kg body weight in 0.5 ml of saline given as above.

Increasing the severity of the surgical interference decreased water intake post surgery compared with pre-treatment intakes.  This effect was only seen during the dark period when rats are most active.  The use of an analgesic (buprenorphine) significantly reduced the magnitude of this effect.

The decrease in water intake after the skin incision only was about 5g and analgesic had no effect on this value.  After laparotomy, the decrease was 10 g, and this was reduced to 5 g by analgesic.  After visceral manipulation the decrease was 18g and was reduced to 9g with analgesic use.