Intravenous catheterization
Under isoflurane aesthesia, SERT+/+ and SERT-/- rats, weighing between 300 and 450 g, received a micro Renathane catheter into the right external jugular vein (for details, see: (Wee et al., 2007). The tubing (0.037” o.d. x 0.023” i.d., Braintree Scientific Inc., USA) was guided subcutaneously to a stainless-steel cannula (22G, Plastics One Inc., USA) at the back of the rat. After surgery, rats were given Flunixin (analgesic drug: 2.5 mg/ml/kg, s.c.) and Cefazolin (antibiotic drug: 15 mg/ml/kg) daily for respectively 3 and 7 days. After surgery, rats were singly housed to prevent damage to the cannula due to cage mates. These rats received a wooden block and nest material as cage enrichment, but not a shelter to prevent collisions with the cannula. The body weight of the animals was monitored daily and full recovery of bodyweight happened within 3 to 5 days. During recovery, no unexpected changes in animal behavior (e.g. no self-grooming, no water intake) were observed. Catheter patency was maintained by daily flushing with 0.2 ml heparinized saline. In case of obstruction of the catheter, the animal was removed from the study.