| Abstract: | 1. The effects of surgery and anaesthesia on adrenaline and noradrenaline plasma levels were investigated in the eel (Anguilla anguilla L.). 2. Effect of surgery: highest values were obtained when putting back the fish in water. Three hours after surgery, adrenaline and noradrenaline plasma levels were always significantly higher than those obtained 24 and 48 hr after surgery. 3. Effect of anaesthesia: anaesthesia only had no effect on adrenaline and noradrenaline plasma levels. 4. It was concluded that the trauma of surgery was mainly responsible for the elevation of CA plasma levels in the eel. A minimum post-operative period of 24 hr should be allowed before any blood sampling for estimation of resting CA plasma levels. Resting adrenaline and noradrenaline plasma levels, 48 hr after surgery, were respectively 1.31 +/- 0.38 and 3.37 +/- 0.41 pmol/ml. |
