Implication of Dp and α1-syntrophin in cellular plasticity in neurohypophysis during water stress in wistar rats

Abstract

The hypothalamic-neurohypophyseal system (NHHS), our study model, due to its extreme sensitivity to physiological fluctuations, such as dehydration. The SHNH consists essentially of magnocellular neurons (NMCs) whose cell bodies are located mainly in the hypothalamic, supraoptic (NSO) and paraventricular (NPV) nuclei, and their axons cross the median eminence (EM) and terminate in the neurohypophysis (NH). At this level, these NMCs secrete two neurohormones into the blood circulation, oxytocin (OT) involved in parturition and lactation, and vasopressin (AVP) which participates in the regulation of hydromineral balance and vasoconstriction. In this system, both at the neuronal and glial levels, the presence of a family of cytoskeletal proteins, the dystrophins (Dp), and the proteins associated with them (DAPs), such as a1-syntrophin. The involvement of these proteins is suggested in different processes, in neuroscretory granules storage, signal transduction and cellular plasticity. For this work, we applied a salt loading 2% NaCl solution for 14 days. We were interested in studying the involvement of dystrophins, mainly Dp71 and α1-syntrophin, not only during this dehydration but also in situations of reversibility by rehydrating the animal for 30 days in neural lobe (LN). We have shown that the 71kDa Dp (Dp71) is the most abundant form revealed in the LN of the control rat. It was localized in nerve endings and pituicytes. α1-syn is located mainly in the pituicyte feet. This study was approached by biochemical approaches, by Western-blotting, and immunohistochemical approaches, in conventional, confocal light microscopy.