The effects of different anaesthetic treatments on the adreno-cortical functions and glucose levels in NZW rabbits

The effects of five anaesthetics on the corteicosterone, cortisol and gluco se concentrations were investigated in the NZW rabbit. Sixty animals were a ssigned to 6 treatment groups (n= 10 per group): control (iv saline solutio n injection), ketamine (10 mg/kg iv) with either xylazine (3 mg/kg iv) or d iazepam (2 mg/kg iv), pentobarbitone (30 mg/kg iv), thiopentone (20 mg/kg i v) and fentanyl/droperidol (1 mg/kg SC). Plasma glucocorticoids were measur ed by competitive enzymeimmunoassay EIA and glucose by an autoanalyzer, pre viously validated for this species in both cases. Blood samples were obtain ed at 6 time-points: before injection, at 10, 30, 60, 120 min and 24 h afte r injection of the anaesthetics/saline. A significant decrease of plasma gl ucocorticoids at 10-60 min was observed in the pentobarbitone and fentanyl/ droperidol groups, whereas the administration of ketamine/diazepam or thiop entone stimulated plasma glucocorticoid release, principally in the recover y period. However, in the ketamine/xylazine group no changes were observed in the glucocorticoid levels, except for a significative increase of cortis ol at 60-120 min. Glucose levels significantly increased after ketamine/dia zepam administration and principally, after ketamine/xylazine treatment. Th e present data suggest that ketamine/xylazine has little effect on glucocor ticoid levels and provides an adequate level of surgical anaesthesia, hence it would be the anaesthetic of choice, although the hyperglycaemic effect after injection has to be considered for any experimental procedures in rab bits.