SUMMARY

A lateral tail vein of the rat is used as the route for continuous infusion. The animal is kept under neuroleptic tranquilisation during the infusion. 69 Various methods have been developed for the continuous infusion of animals. The jugular vein can easily be cannulated, the tube being fixed by means of a subcutaneous tunnel (Dalton, Touraine & Wilson, 1969; Evans, 1970; Harris, 1974). Bezman (1969) cannulated the femoral vein. The continuity of the infusion has been ascertained by relaxing the animal (Bezman, 1969) or by protecting the tube either mechanically or electrically (Dalton et al., 1969; Edmonds & Thompson, 1970). Earlier techniques included an operation during which the cannula was inserted. The purpose of this work was to develop a simple method for continuous intravenous infusion with minimal traumatisation of the rat. MATERIALS AND METHODS Male Wistar rats weighing 250-300 g were used. The anaesthesia was started with light ether anaesthesia, during which a lateral tail vein was cannulated. Then droperidol (1 mg/kg) was injected via the cannula and the animal stayed calm for the initiation of the infusion. Droperidol was infused continuously during the experiment at a rate of 0·16 mgjkgjh. Simultaneously 40 i.u.jkg heparin was given for an hour. The tail was cleaned with ethanol (70 % wjw) and light venous compression was applied to fill the tail veins. A lateral tail vein was punctured with a sterile needle, through which a cannula was inserted as long as resistance appeared (Fig. 1). The needle was then removed and the cannula was fixed to the tail with adhesive tape