Assess the effect of ciliary neurotrophic factor on extracellular level of neuropeptide Y in paraventricular nucleus using microdialysis

In this study we investigated the effect of ciliary neurotrophic factor (CNTF) on dynamic changes in the release of hypothalamic neuropeptide Y (NPY) of freely moving rats using radioimmunoassay-microdialysis procedure. NPY concentrations in paraventricular nucleus (PVN) dialysate rapidly decreased to the lowest point, 47% of basal level (P<0.01), in 30 minutes after intracerebroventricular injection 5 mug CNTF, and then increased slowly to 58%, 78% and 85% of basal level respectively at 60, 90 and 120 min (P<0.05). It became no significant difference with basal level at 150 and 180 min. These results suggested CNTF administration could directly down-regulate NPY release from hypothalamic PVN to reduce food intake and PVN was a target of CNTF´s anorectic effect