Intracerebroventricular injection

Rats were exposed to 10% chloral hydrate (300 mg/kg, ip) to induce anesthesia followed by immobilization in a digital stereotaxic instrument (Stoelting, USA). A hole was drilled in the skull after a midline incision. Drugs were injected slowly with a Hamilton microsyringe into one of the LV under stereotactic guidance (Brega: 1.2±0.4 mm, deep: 3.2±0.4 mm, right to median sagittal plane: 1.4±0.2 mm) over 15 min. An additional 15 min was allowed to prevent drug diffusion. Animals were kept warm and allowed to recover from anesthesia. When the rats were completely awake, they were returned to the cage to rest.