Stimulation of 5-HT2A receptors in the paraventricular hypothalamus attenuates neuropeptide Y-induced hyperphagia through activation of corticotropin releasing factor

The effect of 5-HT1 and 5-HT2 receptor agonists administered into the paraventricular hypothalamus was studied on the hyperphagia caused by neuropeptide Y (NPY) injected into the same area. The 5-HT2A/2C receptor agonist DOI (10–20 nmol/0.5 μl) significantly reduced NPY overeating while the 5-HT1A/1B receptor agonist RU 24969 (3.5–14 nmol/0.5 μl) and the 5-HT1B/2C receptor agonist mCPP (5–20 nmol/0.5 μl) had no such effect. The 5-HT2A receptor antagonist spiperone (5 μg/0.5 μl) and the corticotropin releasing factor antagonist α-helical-CRF9–41 (0.5–1 μg/0.5 μl completely antagonized the effect of 10 nmol DOI.