Data on protein synthesis of deafferented hypothalamic arcuate neurons

Protein synthesizing activity of the rat hypothalamic arcuate nucleus following partial or total deafferentation of the medial basal hypothalamus was studied by light and electron microscopic autoradiography when administering tritiated leucine into the lateral ventricle. There were significantly more grains over the arcuate nucleus 21 days after disconnection of this hypothalamic region than over the intact nucleus. Isolation of a temporal cortical region induced similar changes in the isolated area, although this effect was not so pronounced as in the arcuate region. Data suggest that the protein synthesizing activity of arcuate neurons increases significantly after interruption of neural connections of the medial basal hypothalamus. It is assumed that the effect is primarily due to transneuronal alteration and/or interruption of inhibitory afferents.