RECIPROCAL PATHWAYS BETWEEN MEDULLARY VISCERAL ZONE AND HYPOTHALAMIC PARAVENTRICULAR NUCLEUS OR SUPRAOPTIC NUCLEUS INVOLVED IN HYPEROSMOTIC REGULATION / 解放军医学杂志

ABSTRACT

Objective To elucidate the existence of reciprocal pathways between medullary visceral zone (MVZ) and hypothalamic paraventricular nucleus (PVN) or supraoptic nucleus(SON) following hyperosmotic stimulation. Methods Hyperosmosis was produced in rats by drinking 3% sodium chloride solution. The distributions and expressions of HRP retrogradely labeled neurons, Fos, tyrosine hydroxylase (TH) or vasopressin (VP) positive neuron and glial fibrillary acidic protein (GFAP) positive astrocytes(AST) in MVZ, SON and PVN were observed by quadruplicate labeling methods of WGA HRP retrograde tracing combined with anti Fos, TH (or VP) and GFAP immunohistochemical technique. Results Fos positive neurons within the MVZ, PVN and SON were increased markedly. There was also a marlced increase in GFAP positive structures in the brain, and their distribution pattern was fundamentally similar or analogous to Fos positive neurons in the above mentioned areas. The augmented GFAP structures manifested as hypertrophic cell bodies, with thicker and longer processes. Quadruplicate immunohistochemical staining showed that neurons were surrounded by many AST to form neuron astrocytic complex (N ASC). Conclusion The neurons and AST, as a functional unif in the form of N ASC, might actively participate in modulating osmotic pressure. There was reciprocal osmoregulation pathways between the MVZ and SON or PVN in the brain