Watts A G, Sanchez-Watts G
Department of Biological Sciences, University of Southern California, Los Angeles 90089-2520, USA.
Brain Res. 1995 Jul 31;687(1-2):63-70. doi: 10.1016/0006-8993(95)00451-u.
In the rat, the cellular dehydration induced by water deprivation rapidly increases CRH mRNA in magnocellular neurosecretory neurons, but gradually reduces mRNA levels in hypothalamic paraventricular parvicellular neurosecretory neurons. Using in situ hybridization we investigated a possible role for corticosterone as a mediator of the effects of water deprivation on the levels of CRH mRNA in the paraventricular and supraoptic nuclei. Following adrenalectomy and water deprivation, the reduction of CRH mRNA in the medial parvicellular part of the paraventricular nucleus was inhibited. However, replacement of low-doses of corticosterone to dehydrated adrenalectomized animals was not sufficient to reduce parvicellular CRH mRNA levels to those seen in intact dehydrated animals. Neither adrenalectomy nor corticosterone replacement had any effect on the increased CRH mRNA levels in magnocellular neurosecretory neurons. We conclude that an intact adrenal gland is required for the decreased levels of CRH mRNA seen during water deprivation in parvicellular paraventricular neurosecretory neurons, but not magnocellular neurosecretory neurons. These effects may be mediated by the increased corticosterone secretion seen during water deprivation.
在大鼠中，缺水诱导的细胞脱水迅速增加了大细胞神经分泌神经元中的促肾上腺皮质激素释放激素（CRH）mRNA，但逐渐降低了下丘脑室旁小细胞神经分泌神经元中的mRNA水平。我们使用原位杂交技术研究了皮质酮作为缺水对室旁核和视上核中CRH mRNA水平影响的介质的可能作用。肾上腺切除和缺水后，室旁核内侧小细胞部分中CRH mRNA的减少受到抑制。然而，给脱水的肾上腺切除动物补充低剂量的皮质酮不足以将小细胞CRH mRNA水平降低到完整脱水动物中的水平。肾上腺切除和皮质酮替代对大细胞神经分泌神经元中CRH mRNA水平的增加均无任何影响。我们得出结论，完整的肾上腺对于缺水期间室旁小细胞神经分泌神经元中CRH mRNA水平的降低是必需的，但对于大细胞神经分泌神经元则不是。这些影响可能由缺水期间皮质酮分泌增加介导。
