Effect of haloperidol treatment on immunoreactive neuropeptide Y secretion into lateral cerebral ventricle of rats.

The study aimed to evaluate the effect of acute and 14-day haloperidol treatment (2 mg/kg ip) on release of neuropeptide Y-like immunoreactivity (NPY-LI) in non-anesthetized, freely moving rats by means of push-pull perfusion of the lateral cerebral ventricle. Twenty four hours after a single haloperidol injection NPY-LI release decreased by 15% (p < 0.05). No alterations were detected after 14-day haloperidol treatment. The study has confirmed that haloperidol alters the activity of neuropeptide Y system in the rat brain and suggested that acute haloperidol treatment inhibits the activity of the neuropeptide Y system at least in some brain structures surrounding the cerebral ventricles. The presented results have been discussed in view of our previous findings describing the haloperidol-induced changes in NPY-LI and NPY mRNA levels in the rat brain.