Isolation- and dehydration-induced changes in neuropeptide gene expression in the sheep hypothalamus

1993 ◽  
Vol 11 (2) ◽  
pp. 181-189 ◽  
Author(s):  
S G Matthews ◽  
R F Parrott ◽  
D J S Sirinathsinghji
Keyword(s):  
Gene Expression ◽  
Supraoptic Nucleus ◽  
Plasma Osmolality ◽  
Hybridization Histochemistry ◽  
In Situ Hybridization Histochemistry ◽  
Mrna Content ◽  
Powerful Stimulus ◽  
Stress Isolation ◽  
Induced Changes

ABSTRACT Changes in neuropeptide gene expression in the hypothalami of sheep subjected to psychological stress (isolation, 1 h; n=3) or dehydration (48 h; n=3) were examined using in-situ hybridization histochemistry. Compared with non-stressed euhydrated control animals (n=3), isolation induced significant accumulation of mRNA for corticotrophin-releasing hormone, pro-enkephalin and pro-dynorphin (DYN) in the paraventricular nucleus (PVN), but no change in mRNA content within the supraoptic nucleus (SON). By contrast, dehydration significantly increased DYN mRNA in the magnocellular neurones of the PVN and SON. However, neither isolation nor dehydration altered the expression of mRNA for vasopressin (AVP) in either the PVN or the SON. These results indicate that in the ovine hypothalamus (1) stress represents a powerful stimulus to co-ordinated neuropeptide synthesis and (2) expression of DYN mRNA and AVP mRNA may be independently regulated during changes in plasma osmolality.

Gene expression in the rat supraoptic nucleus induced by chronic hyperosmolality versus hyposmolality

2000 ◽  
Vol 279 (4) ◽  
pp. R1239-R1250 ◽  
Author(s):  
Eric Glasgow ◽  
Takashi Murase ◽  
Bingjun Zhang ◽  
Joseph G. Verbalis ◽  
Harold Gainer
Keyword(s):  
Gene Expression ◽  
Supraoptic Nucleus ◽  
Cdna Libraries ◽  
Global Changes ◽  
Cdna Clones ◽  
Mrna Levels ◽  
Magnocellular Neurons ◽  
In Situ Hybridization Histochemistry ◽  
Functional Classes

Magnocellular neurons of the hypothalamo-neurohypophysial system play a fundamental role in the maintenance of body homeostasis by secreting vasopressin and oxytocin in response to systemic osmotic perturbations. During chronic hyperosmolality, vasopressin and oxytocin mRNA levels increase twofold, whereas, during chronic hyposmolality, these mRNA levels decrease to 10–20% of that of normoosmolar control animals. To determine what other genes respond to these osmotic perturbations, we have analyzed gene expression during chronic hyper- versus hyponatremia. Thirty-seven cDNA clones were isolated by differentially screening cDNA libraries that were generated from supraoptic nucleus tissue punches from hyper- or hyponatremic rats. Further analysis of 12 of these cDNAs by in situ hybridization histochemistry confirmed that they are osmotically regulated. These cDNAs represent a variety of functional classes and include cytochrome oxidase, tubulin, Na+-K+-ATPase, spectrin, PEP-19, calmodulin, GTPase, DnaJ-like, clathrin-associated, synaptic glycoprotein, regulator of GTPase stimulation, and gene for oligodendrocyte lineage-myelin basic proteins. This analysis therefore suggests that adaptation to chronic osmotic stress results in global changes in gene expression in the magnocellular neurons of the supraoptic nucleus.

Effect of leptin administration versus re-feeding on hypothalamic neuropeptide gene expression in fasted male rats

2004 ◽  
Vol 82 (12) ◽  
pp. 1128-1134 ◽  
Author(s):  
Edward D McAlister ◽  
Dean A Van Vugt
Keyword(s):  
Gene Expression ◽  
Leptin Receptor ◽  
Primary Source ◽  
Male Rats ◽  
In Situ Hybridization Histochemistry ◽  
Reproductive Axis ◽  
Physiological Relevance ◽  
Long Form ◽  
Induced Changes

Adipocytes are the primary source of circulating leptin. Leptin inhibits eating, increases metabolism, and stimulates the reproductive axis. Numerous hypothalamic neuropeptides have been implicated in leptin's behavioral and neuroendocrine effects, including neuropeptide Y (NPY) and cocaine- and amphetamine-regulated transcript (CART). The aim of this study was to investigate the physiological relevance of leptin's signaling of nutritional status by comparing the effects of leptin with the effects of re-feeding on fasting-induced changes in the expression of the long form of the leptin receptor (Ob-Rb), NPY, and CART. Adult male rats were fasted for 48 h and treated with either intra cere broventricular (i.c.v.) or subcutaneous (s.c.) leptin throughout the fast, or fed ad libitum for 24 h after terminating the fast. Expression of NPY, Ob-Rb, and CART mRNA in the arcuate nucleus (ARC) was determined by in situ hybridization histochemistry and compared with vehicle-treated fed or fasted controls. Fasting increased NPY and Ob-Rb expression and decreased CART expression in the ARC. Leptin (regardless of route) and re-feeding were equally effective in normalizing CART mRNA expression. A similar trend was observed with Ob-Rb expression. In contrast, neither re-feeding nor s.c. leptin reversed the increased expression of NPY that was induced by fasting. Only i.c.v. leptin was effective in this regard. Our results indicate leptin and re-feeding are equally effective in normalizing fasting-induced changes in CART and Ob-Rb expression, but less effective in normalizing NPY expression. These results suggest that leptin is the primary nutritional signal regulating CART and Ob-Rb expression in the ARC, and highlight potential differences between CART and NPY neuron sensitivity to leptin signaling.Key words: CART, leptin receptor, NPY, neuropeptide gene expression, fasting, refeeding, hypothalamus.

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