Vasopressin and oxytocin neurones of hypothalamic supraoptic and paraventricular nuclei co-express mRNA for type-1 andType-2 corticotropin-releasing hormone receptors
Vasopressin and oxytocin neurones of hypothalamic supraoptic and paraventricular nuclei co-express mRNA for type-1 andType-2 corticotropin-releasing hormone receptors
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DOI：
10.1046/j.1365-2826.2000.00528.x
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发表时间：
2000-09-01
影响因子：
3.2
通讯作者：
Aguilera, G
中科院分区：
文献类型：
--
作者：
Arima, H;Aguilera, G
促肾上腺皮质激素释放激素（CRH）受体1型（CRHR-1）和2型（CRHR-2 α）在下丘脑视上核（SON）和室旁核（PVN）的存在，以及静脉注射CRH和尿皮质素对精氨酸加压素（AVP）和催产素释放的影响，表明CRH配体在AVP调节中起作用。本研究采用S-35标记CRHR-1或CRHR-2 α和地高辛标记AVP、催产素或CRH核糖核酸探针的双标记原位杂交技术，检测CRHR-1或CRHR-2 α mRNA在对照组和刺激组大鼠SON和PVN中的定位。大鼠接受腹膜内高渗盐水（1.5 M）注射或等渗盐水注射（对照），或2% NaCl摄入（盐负荷）或自来水（对照），持续12天。CRHR-1 mRNA在对照组大鼠SON和PVN中未检测到，但在腹腔注射高渗盐水后4 h或盐负荷12 d后CRHR-1 mRNA的表达显著增加。在地高辛标记的细胞中，53%的SON和90%的PVN在腹腔注射高渗盐水后共表达CRHR-1 mRNA。在催产素能神经元中，73%的SON和91%的PVN在腹膜内注射高渗盐水后显示CRHR-1放射自显影颗粒高于背景水平。此外，腹膜内高渗盐水诱导小细胞PVN中地高辛-CRH染色细胞中CRHR-1 mRNA表达。CRHR-2 α转录本在基础条件下存在于SON和PVN中，并且盐负荷而不是急性腹膜内高渗盐水注射进一步刺激了这种表达。双标记原位杂交显示CRHR-2 α mRNA与AVP和催产素mRNA在SON共定位。这些研究支持CRH和urocortin调节下丘脑-神经垂体系统的作用，并表明肽在大细胞神经元中的直接作用。
The presence of corticotropin-releasing hormone (CRH) receptors type-1 (CRHR-1) and type-2 (CRHR-2 alpha) in the hypothalamic supraoptic (SON) and paraventricular (PVN) nuclei, and the effects of i.c.v. injection of CRH and urocortin on arginine vasopressin (AVP) and oxytocin release, have suggested that CRH ligands have a role in osmoregulation. In this study, double labelling in situ hybridization using S-35-labelled CRHR-1 or CRHR-2 alpha and digoxigenin-labelled AVP, oxytocin or CRH riboprobes was employed to examine the localization of CRHR-1 or CRHR-2 alpha mRNA in the SON and PVN of control and osmotically stimulated rats. Rats received an i.p. hypertonic saline (1.5 M) injection or isotonic saline injection (controls), or 2% NaCl intake (salt loading) or tap water (controls) for 12 days. While CRHR-1 mRNA was undetectable in the SON and PVN in control rats, its expression was increased markedly at 4 h after i.p. hypertonic saline injection or after 12 days salt loading. Of the cells labelled with digoxigenin-AVP, 53% in the SON and 90% in the PVN coexpressed CRHR-1 mRNA after i.p. hypertonic saline injection. In oxytocinergic neurones, 73% in the SON and 91% in the PVN showed CRHR-1 autoradiographic grains higher than background levels after i.p. hypertonic saline injection. In addition, i.p. hypertonic saline induced CRHR-1 mRNA expression in digoxigenin-CRH stained cells in the parvocellular PVN. CRHR-2 alpha transcripts were present in both the SON and PVN under basal conditions, and salt loading, but not acute i.p. hypertonic saline injection, further stimulated this expression. Double labelling in situ hybridization showed colocalization of CRHR-2 alpha mRNA with AVP and oxytocin mRNA in the SON. These studies support a role for CRH and urocortin regulating the hypothalamo-neurohypophyseal system, and suggest a direct action of the peptides in the magnocellular neurones.