The effects of transverse cuts caudal to the preoptic recess on the fine structure of paraventricular nuclei in XXXX .

@entity35 @entity2011 @entity6085
Lesions of the tissue surrounding the preoptic recess (anteroventral third ventricle (AV3V) region) have been shown to severely impair normal mechanisms of body fluid homeostasis, including the antidiuretic response. In an earlier investigation of the pathways affected by these lesions, coronal cuts were placed between the level of the organum vasculosum lamina terminalis in the AV3V region and the level of the supraoptic nuclei. @entity35 with such cuts exhibited hyperdipsia and @entity2011 , but their plasma levels of @entity6085 ( @entity6085 ) were elevated. The fine structure of the supraoptic nucleus, a major site of @entity6085 production, and of the neural lobe of the hypophysis, where @entity6085 is released, were observed in @entity35 with similar cuts. Although neural lobes showed evidence of hormone depletion and degenerating axons and terminals were present in supraoptic nuclei, there was no morphological evidence that neurosecretory cell bodies in supraoptic nuclei were affected by these cuts. Therefore, in this investigation we observed the ultrastructural effects of such cuts on paraventricular nuclei, which are the other major source of @entity6085 . Degenerating axons and terminals were common in paraventricular nuclei of lesioned @entity35 , both in the major magnocellular subnucleus and in the periventricular region. Cell bodies and nuclei of neurosecretory cells were not significantly larger in lesioned animals, but morphometric evaluations revealed dispersion of the Golgi complex and alterations in the rough endoplasmic reticulum of the cells. In addition, more multiple nucleoli were present, and nucleoli tended to lie adjacent to the nuclear envelope more frequently. We conclude that the neurosecretory cells in the paraventricular nuclei become more active in @entity35 with these knife cuts.
