Expression of Immediate Early Genes and Vasopressin Heteronuclear RNA in the Paraventricular and Supraoptic Nuclei of Rats After Acute Osmotic Stimulus

Abstract

Monitoring the expression of immediate early genes (IEGs) is useful for following stress-induced cellular responses in the neuroendocrine system. We have examined the transcriptional activities of four IEGs (c-fos, junB, NGFI-A and NGFI-B) and of the arginine vasopressin (AVP) gene in the hypothalamic paraventicular (PVN) and supraoptic nuclei (SON) of rats after acute osmotic stimuli, using in situ hybridization histochemistry. After intraperitoneal (i.p.) administration of hypertonic saline (2% body weight, 900 mOsm/kg), the expression levels of all IEG mRNAs were increased significantly both in the PVN and SON at as early as 10 min, peaked at 30 min and remained elevated until 60 min. The expression of AVP heteronuclear (hn)RNA also peaked at 30 min, and remained elevated until 180 min. Thirty min after i.p. administration of hypertonic saline (600 mOsm/kg), the expression levels of all IEG mRNAs in the PVN and SON were significantly increased in comparison with those after i.p. administration of isotonic saline (290 mOsm/kg). Regression analysis revealed that expression levels of the IEG mRNAs and AVP hnRNA were positively correlated with the plasma concentration of sodium, and the rates of increase of the expression levels of all IEG mRNAs were similar. The expression levels of all IEG mRNAs examined are useful markers for following the changes of the AVP gene transcription in the PVN and SON after acute osmotic stimuli in rats.

Transcription Factor Expression in the Hypothalamo-Neurohypophyseal System of the Dehydrated Rat: Upregulation of Gonadotrophin Inducible Transcription Factor 1 mRNA Is Mediated by cAMP-Dependent Protein Kinase A

“…shown to be upregulated in the SON after dehydration (Carter and Murphy, 1990;Sharp et al, 1991;Luckman et al, 1996;Miyata et al, 2001b;Cunningham et al, 2004;Ji et al, 2005;Kawasaki et al, 2005;Penny et al, 2005;Gottlieb et al, 2006). Here we identify JunD as also being upregulated (supplemental Table 3, available at www.jneurosci.org as supplemental material), an observation that we confirmed by in situ hybridization and immunocytochemistry (Yao et al, unpublished observation).…”

“…Effect of water deprivation on the distribution of cells expressing Atf4, Cebpb, Creb3l1, Giot1, and Giot2␤ in the SON and PVN of the control (C) and dehydrated (D been shown to be induced by cAMP intracellular signaling pathways through a CRE (Yazawa et al, 2003). Furthermore, the Giot1 promoter has been shown recently to be a target of the orphan nuclear receptor Nr4a1 (nuclear receptor subfamily 4, group A, member 1) (also known as Nur77 or NGFIB) (Song et al, 2006) transcription factor, which is also upregulated in the SON after dehydration (supplemental Table 3, available at www.jneurosci.org as supplemental material) (Luckman, 1997;Kawasaki et al, 2005). Nr4a1 is also known to be under the control of cAMP pathways (Humphries et al, 2004).…”

The Temporal Sequence of Gut Peptide–CNS Interactions TrackedIn Vivoby Magnetic Resonance Imaging

“…Detection of a change in SI in a hypothalamic region may therefore reflect a change in neuronal activity at that time point, or it may correspond to the earliest time point at which a change in neuronal activity becomes detectable, once sufficient Mn 2ϩ ions have penetrated into that region. Peripheral injection of hypertonic NaCl strongly induces FLI in the SON and PVN (Han and Rowland, 1996;Xiong and Hatton, 1996;Kawasaki et al, 2005). The SON is anatomically more distant from the ME than the Arc, and this is reflected in the relatively slow rate of rise in SI over the 2 h of each scan.…”

In vivo processing and release into the circulation of GFP fusion protein in arginine vasopressin enhanced GFP transgenic rats: response to osmotic stimulation

“…Substantial evidence has demonstrated that the expression level and release of AVP are both significantly increased by osmotic stimulation [8,24,25]. Recently, it has also been reported that GFP signals in the hypothalamus and posterior pituitary of AVP-eGFP Tg rats are considerably amplified by saltloading [9].…”