The Arcuate Nucleus Is the Major Source for Neuropeptide Y-Innervation of Thyrotropin-Releasing Hormone Neurons in the Hypothalamic Paraventricular Nucleus1

• DOI: 10.1210/endo.139.7.6113
• Publication Date: 2014-01-08T11:09:13Z
• Authors: Gábor Légrádi; Ronald M. Lechan
• Keywords: Parvocellular cell

Neuropeptide Y (NPY) immunoreactive (-ir) nerve fibers densely innervate hypophysiotropic TRH perikarya and dendrites in the hypothalamic paraventricular nucleus (PVN). To evaluate contribution of arcuate (Arc) to this innervation, effect Arc ablation by neonatal monosodium glutamate (MSG) treatment on density NPY-fibers contacting neurons PVN was investigated. After lesioned animals vehicle-treated controls reached adulthood, number contacts between NPY-ir boutons TRH-ir determined double-immunostained sections. In controls, numerous terminals were observed, confirming earlier findings. MSG resulted a marked reduction size also NPY-perikarya with concomitant 82.4 ± 2.1% relative NPY first order medial parvocellular periventricular subdivisions PVN. contrast, lesioning ascending adrenergic bundle brain stem caused no statistically significant change NPY-terminals close apposition These data confirm findings that NPY-containing axon further demonstrate potentially important anatomical relationship NPY-producing neurons.