2.2. Surgical Techniques

A drug infusion cannula was implanted above the basolateral amygdala (BLA) in 24 rats by stereotaxic surgery. After intraperitoneal anesthesia with ketamine (100 mg/kg) and xylazine (6 mg/kg), the rats were placed in the stereotaxic apparatus (Stoelting, Wood Dale, IL) on a heating pad. The incisor bar was set at −3.3 mm to make the skull flat. Under aseptic conditions, a 23 gauge guide cannula (Plastics One, Roanoke, VA) was inserted into the BLA bilaterally (2.9 mm posterior to the bregma, 5.0 mm lateral to the midline, and 8.5 mm ventral to the skull surface) [16]. Two screws were then placed into the skull as anchors. The guide cannula was secured using dental acrylic. After surgery, ketoprofen (10 mg/kg, im) was administered. Three days were allowed for rats to recover prior to subsequent experimental procedures.