1.   The rats were anaesthetised either by a subcutaneous injection of urethane or an intraperitoneal injection of sodium phenobarbital.

2.   After sloughing of the damaged cells from the surface of the mucosa, no sign of recovery or re-epithelialisation was noted in urethane anaesthetised rats.

3.   This finding is consistent with other reports showing that restitution of the damaged mucosa takes place in barbiturate anaesthetised rats.

4.   After an overnight fast in cages designed to avoid coprophagia, rats were anaesthetised and a tracheostomy was performed.

5.   After an overnight fast, rats were anaesthetised and a tracheostomy was performed.