A new technique for long term, stress free, cannulation of the lateral ventricle in postpubertal, freely moving, pigs.

Intracerebroventricular (ICV) cannulation in adolescent and adult pigs has some unique problems. Placement of the cannula is very difficult due to large individual variability in size and structure of the skull and frontal sinus. Furthermore, the rough behavior of the animals makes it necessary to restrain the animals for ICV treatment, which is disadvantageous when studying responses to stress. In the present study, we developed and employed a cannulation system for the pig brain, based on landmarks on the neurocranium, that enabled us to perform ICV treatment in freely moving post pubertal animals over a long period of time. Furthermore, plasma cortisol concentrations have been determined in freely moving pigs treated ICV with naltrexone or a-CSF (control) to validate the present ICV method for effectivity and stressfulness.