scholarly journals Immunolesion of Norepinephrine and Epinephrine Afferents to Medial Hypothalamus Alters Basal and 2-Deoxy-d-Glucose-Induced Neuropeptide Y and Agouti Gene-Related Protein Messenger Ribonucleic Acid Expression in the Arcuate Nucleus

Endocrinology ◽  
2003 ◽  
Vol 144 (1) ◽  
pp. 75-83 ◽  
Author(s):  
G. S. Fraley ◽  
S. Ritter
Keyword(s):  
Gene Expression ◽  
In Situ Hybridization ◽  
Food Intake ◽  
Neuropeptide Y ◽  
Arcuate Nucleus ◽  
Special Importance ◽  
Related Protein ◽  
Medial Hypothalamus ◽  
Agouti Gene

Abstract Neuropeptide Y (NPY) and agouti gene-related protein (AGRP) are orexigenic peptides of special importance for control of food intake. In situ hybridization studies have shown that NPY and AGRP mRNAs are increased in the arcuate nucleus of the hypothalamus (ARC) by glucoprivation. Other work has shown that glucoprivation stimulates food intake by activation of hindbrain glucoreceptor cells and requires the participation of rostrally projecting norepinephrine (NE) or epinephrine (E) neurons. Here we determine the role of hindbrain catecholamine afferents in glucoprivation-induced increase in ARC NPY and AGRP gene expression. The selective NE/E immunotoxin saporin-conjugated antidopamineβ-hydroxylase (anti-dβh) was microinjected into the medial hypothalamus and expression of AGRP and NPY mRNA was analyzed subsequently in the ARC under basal and glucoprivic conditions using 33P-labeled in situ hybridization. Saporin-conjugated anti-dβh virtually eliminated dβh-immunoreactive terminals in the ARC without causing nonspecific damage. These lesions significantly increased basal but eliminated 2-deoxy-d-glucose-induced increases in AGRP and NPY mRNA expression. Results indicate that hindbrain catecholaminergic neurons contribute to basal NPY and AGRP gene expression and mediate the responsiveness of NPY and AGRP neurons to glucose deficit. Our results also suggest that catecholamine neurons couple potent orexigenic neural circuitry within the hypothalamus with hindbrain glucose sensors that monitor brain glucose supply.

scholarly journals Altered Expression of Agouti-Related Protein and Its Colocalization with Neuropeptide Y in the Arcuate Nucleus of the Hypothalamus during Lactation*

Endocrinology ◽  
1999 ◽  
Vol 140 (6) ◽  
pp. 2645-2650 ◽  
Author(s):  
Peilin Chen ◽  
Chien Li ◽  
Carrie Haskell-Luevano ◽  
Roger D. Cone ◽  
M. Susan Smith
Keyword(s):  
In Situ Hybridization ◽  
Food Intake ◽  
Neuropeptide Y ◽  
Arcuate Nucleus ◽  
Mrna Levels ◽  
Related Protein ◽  
Altered Expression ◽  
Caudal Portion ◽  
Agouti Related Protein

Abstract During lactation, the levels of neuropeptide Y (NPY), which plays an important role in mediating food intake, are significantly elevated in a number of hypothalamic areas, including the arcuate nucleus (ARH). To identify additional hypothalamic systems that might be important in mediating the increase in food intake and alterations in energy homeostasis during lactation, the present studies examined the expression of agouti-related protein (AGRP), a recently described homologue of the skin agouti protein. AGRP is found in the hypothalamus and has been suggested to play an important role in the regulation of food intake. In the first experiment, animals were studied during diestrus of the estrous cycle, a stage of the cycle when estrogen levels are basal and similar to lactation, or during days 12–13 postpartum. Lactating animals had their litters adjusted to eight pups on day 2 postpartum. Brain tissue sections were used to measure AGRP messenger RNA (mRNA) levels by in situ hybridization. AGRP mRNA signal was found mostly in the ventromedial portion of the ARH, which has been shown to contain a high density of NPY neurons. A significant increase in AGRP mRNA content was observed in the mid- to caudal portion of the ARH of lactating animals compared with diestrous females. No difference was found in the rostral portion of the ARH. In the second experiment, double-label in situ hybridization for AGRP and NPY was performed in lactating animals to determine the extent of colocalization of the two peptides in the ARH, using 35S-labeled and digoxigenin-labeled antisense complementary RNA probes. It was found that almost all of the NPY-positive neurons throughout the ARH also expressed AGRP mRNA signal. Furthermore, AGRP expression was confined almost exclusively to NPY-positive neurons. Thus, the present study showed that during lactation, AGRP gene expression was significantly elevated in a subset of the AGRP neurons in the ARH. The high degree of colocalization of AGRP and NPY, coupled with previous reports from our laboratory demonstrating increased NPY expression in the ARH in response to suckling, suggests that AGRP and NPY are coordinately regulated and may be involved in the increase in food intake during lactation.

Influence of photoperiod and gonadal status on food intake, adiposity, and gene expression of hypothalamic appetite regulators in a seasonal mammal

2007 ◽  
Vol 292 (1) ◽  
pp. R242-R252 ◽  
Author(s):  
Chantacha Anukulkitch ◽  
Alexandra Rao ◽  
Frank R. Dunshea ◽  
Dominique Blache ◽  
Gerald A. Lincoln ◽  
...  
Keyword(s):  
Gene Expression ◽  
Food Intake ◽  
Arcuate Nucleus ◽  
Leptin Receptor ◽  
Reproductive Axis ◽  
Pomc Gene ◽  
Gonadal Status ◽  
Long Photoperiod ◽  
Refractory Phase

We studied the effects of photoperiod on metabolic profiles, adiposity, and gene expression of hypothalamic appetite-regulating peptides in gonad-intact and castrated Soay rams. Groups of five to six animals were studied 6, 18, or 30 wk after switching from long photoperiod (LP: 16 h of light) to short photoperiod (SP: 8 h of light). Reproductive and metabolic indexes were measured in blood plasma. Expression of neuropeptide Y (NPY), proopiomelanocortin (POMC), and leptin receptor (ObRb) in the arcuate nucleus was measured using in situ hybridization. Testosterone levels of intact animals were low under LP, increased to a peak at 16 wk under SP, and then declined. Voluntary food intake (VFI) was high under LP in both intact and castrated animals, decreased to a nadir at 12–16 wk under SP, and then recovered, but only in intact rams as the reproductive axis became photorefractory to SP. NPY gene expression varied positively and POMC expression varied negatively with the cycle in VFI, with differences between intact and castrate rams in the refractory phase. ObRb expression decreased under SP, unrelated to changes in VFI. Visceral fat weight also varied between the intact and castrated animals across the cycle. We conclude that 1) photoperiodic changes in VFI reflect changes in NPY and POMC gene expression, 2) changes in ObRb gene expression are not necessarily determinants of changes in VFI, 3) gonadal status affects the pattern of VFI that changes with photoperiod, and 4) in the absence of gonadal factors, animals can eat less but gain adiposity.

Expression of a Novel Neuropeptide Y Receptor Subtype Involved in Food Intake: An in Situ Hybridization Study of Y5 mRNA Distribution in Rat Brain

2000 ◽  
Vol 165 (1) ◽  
pp. 90-100 ◽  
Author(s):  
Margaret M. Durkin ◽  
Mary W. Walker ◽  
Kelli E. Smith ◽  
Eric L. Gustafson ◽  
Christophe Gerald ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Food Intake ◽  
Neuropeptide Y ◽  
Rat Brain ◽  
Receptor Subtype ◽  
Hybridization Study ◽  
Neuropeptide Y Receptor

scholarly journals LGR4 and Its Ligands, R-Spondin 1 and R-Spondin 3, Regulate Food Intake in the Hypothalamus of Male Rats

Endocrinology ◽  
2014 ◽  
Vol 155 (2) ◽  
pp. 429-440 ◽  
Author(s):  
Ji-Yao Li ◽  
Biaoxin Chai ◽  
Weizhen Zhang ◽  
Danielle M. Fritze ◽  
Chao Zhang ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Food Intake ◽  
Neuropeptide Y ◽  
Paraventricular Nucleus ◽  
Median Eminence ◽  
Energy Homeostasis ◽  
Male Rats ◽  
The Third ◽  
The Brain

The hypothalamus plays a key role in the regulation of feeding behavior. Several hypothalamic nuclei, including the arcuate nucleus (ARC), paraventricular nucleus, and ventromedial nucleus of the hypothalamus (VMH), are involved in energy homeostasis. Analysis of microarray data derived from ARC revealed that leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4) is highly expressed. LGR4, LGR5, and LGR6 form a subfamily of closely related receptors. Recently, R-spondin (Rspo) family proteins were identified as ligands of the LGR4 subfamily. In the present study, we investigated the distribution and function of LGR4–LGR6 and Rspos (1–4) in the brain of male rat. In situ hybridization showed that LGR4 is expressed in the ARC, VMH, and median eminence of the hypothalamus. LGR4 colocalizes with neuropeptide Y, proopiomelanocortin, and brain-derived neurotrophic factor neurons. LGR5 is not detectable with in situ hybridization; LGR6 is only expressed in the epithelial lining of the lower portion of the third ventricle and median eminence. Rspo1 is expressed in the VMH and down-regulated with fasting. Rspo3 is expressed in the paraventricular nucleus and also down-regulated with fasting. Rspos 1 and 3 colocalize with the neuronal marker HuD, indicating that they are expressed by neurons. Injection of Rspo1 or Rspo3 into the third brain ventricle inhibited food intake. Rspo1 decreased neuropeptide Y and increased proopiomelanocortin expression in the ARC. Rspo1 and Rspo3 mRNA is up-regulated by insulin. These data indicate that Rspo1 and Rspo3 and their receptor LGR4 form novel circuits in the brain to regulate energy homeostasis.

scholarly journals Basomedial Hypothalamic Injections of Neuropeptide Y Conjugated to Saporin Selectively Disrupt Hypothalamic Controls of Food Intake

Endocrinology ◽  
2005 ◽  
Vol 146 (3) ◽  
pp. 1179-1191 ◽  
Author(s):  
Kishor Bugarith ◽  
Thu T. Dinh ◽  
Ai-Jun Li ◽  
Robert C. Speth ◽  
Sue Ritter
Keyword(s):  
Neuropeptide Y ◽  
Arcuate Nucleus ◽  
Retrograde Transport ◽  
Related Protein ◽  
Y1 Receptor ◽  
Npy Receptor ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Glucoprivic Feeding ◽  
Agouti Gene

Neuropeptide Y (NPY) conjugated to saporin (NPY-SAP), a ribosomal inactivating toxin, is a newly developed compound designed to selectively target and lesion NPY receptor-expressing cells. We injected NPY-SAP into the basomedial hypothalamus (BMH), just dorsal to the arcuate nucleus (ARC), to investigate its neurotoxicity and to determine whether ARC NPY neurons are required for glucoprivic feeding. We found that NPY-SAP profoundly reduced NPY Y1 receptor and αMSH immunoreactivity, as well as NPY, Agouti gene-related protein (AGRP), and cocaine and amphetamine-related transcript mRNA expression in the BMH. NPY-SAP lesions were localized to the injection site with no evidence of retrograde transport by hindbrain NPY neurons with BMH terminals. These lesions impaired responses to intracerebroventricular (icv) leptin (5 μg/5 μl·d) and ghrelin (2 μg/5 μl), which are thought to alter feeding primarily by actions on ARC NPY/AGRP and proopiomelanocortin/cocaine and amphetamine-related transcript neurons. However, the hypothesis that NPY/AGRP neurons are required downstream mediators of glucoprivic feeding was not supported. Although NPY/AGRP neurons were destroyed by NPY-SAP, the lesion did not impair either the feeding or the hyperglycemic response to 2-deoxy-d-glucose-induced blockade of glycolysis use. Similarly, responses to glucagon-like peptide-1 (GLP-1, 5 μg/3 μl icv), NPY (5 μg/3 μl icv), cholecystokinin octapeptide (4 μg/kg ip), and β-mercaptoacetate (68 mg/kg ip) were not altered by the NPY-SAP lesion. Thus, NPY-SAP destroyed NPY receptor-expressing neurons in the ARC and selectively disrupted controls of feeding dependent on those neurons but did not disrupt peptidergic or metabolic controls dependent upon circuitry outside the BMH.

Ontogeny of neuropeptide Y expression in response to deprivation in lean Zucker rat pups

1998 ◽  
Vol 275 (2) ◽  
pp. R466-R470 ◽  
Author(s):  
Timothy J. Kowalski ◽  
Thomas A. Houpt ◽  
Jeongwon Jahng ◽  
Nori Okada ◽  
Streamson C. Chua ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Neuropeptide Y ◽  
Arcuate Nucleus ◽  
Maternal Deprivation ◽  
The Other ◽  
Zucker Rat ◽  
Adult Rats ◽  
Rat Pups

Hypothalamic neuropeptide Y (NPY) activity is believed to play an important role in the response to food deprivation in adult rats. Little is known, however, about the role of the hypothalamic NPY system in the control of food intake in the preweanling rat. To address this issue, we examined the effect of deprivation on arcuate nucleus preproNPY expression in lean Zucker rat pups, using in situ hybridization. PreproNPY expression within the arcuate nucleus was localized to cells in the medial portion. Twenty-four hours of food, water, and maternal deprivation significantly increased the relative abundance of preproNPY mRNA in pups on postnatal day (P) 2, P9, P12, and P15 by 14–31%. This response, however, was not observed on P5. The absence of an effect on P5 and the magnitude of the response at the other ages tested were not correlated with the amount of weight lost during deprivation.

scholarly journals Long Term Exendin-4 Treatment Reduces Food Intake and Body Weight and Alters Expression of Brain Homeostatic and Reward Markers

Endocrinology ◽  
2014 ◽  
Vol 155 (9) ◽  
pp. 3473-3483 ◽  
Author(s):  
Yan Yang ◽  
Alexander A. Moghadam ◽  
Zachary A. Cordner ◽  
Nu-Chu Liang ◽  
Timothy H. Moran
Keyword(s):  
Gene Expression ◽  
Body Weight ◽  
Food Intake ◽  
Repeated Administration ◽  
Reduce Food Intake ◽  
Related Protein ◽  
Sprague Dawley ◽  
Long Acting ◽  
Rebound Increase ◽  
Agouti Gene

Abstract Repeated administration of the long-acting glucagon-like peptide 1 receptor agonist exendin-4 (EX-4) has been shown to reduce food intake and body weight and do so without a rebound increase in food intake after treatment termination. The current study examines the neural mechanisms underlying these actions. After 6 weeks of maintenance on a standard chow or a high-fat (HF) diet, male Sprague Dawley rats were treated with EX-4 (3.2 μg/kg, ip, twice a day) or vehicle for 9 consecutive days. Food intake and body weight (BW) were monitored daily. Expression of the genes for the hypothalamic arcuate nucleus (ARC) peptides proopiomelanocortin (POMC), neuropeptide Y (NPY), and agouti gene-related protein was determined. Expression of the dopamine precursor tyrosine hydroxylase (TH) gene in the ventral tegmental area and genes for dopamine receptors 1 (D1R) and dopamine receptor 2 in the nucleus accumbens were also determined. Pair-fed groups were included to control for the effects of reduced food intake and BW. Treatment with EX-4 significantly decreased food intake and BW over the 9-day period in both the standard chow and HF groups. HF feeding decreased POMC without changing NPY/agouti gene-related protein gene expression in the ARC. Treatment with EX-4 increased POMC and decreased NPY expression independent of the reduction of food intake and BW. Mesolimbic TH and D1R gene expression were decreased significantly in chronic HF diet-fed rats, and these changes were reversed in both EX-4 and pair-fed conditions. These results suggest a role for increased POMC and decreased NPY expression in the ARC in the effects of EX-4 on food intake and BW. Our findings also suggest that EX-4 induced the recovery of mesolimbic TH and D1R expression in HF diet-fed rats may be secondary to HF intake reduction and/or weight loss.

scholarly journals Kisspeptin Cells in the Ewe Brain Respond to Leptin and Communicate with Neuropeptide Y and Proopiomelanocortin Cells

Endocrinology ◽  
2010 ◽  
Vol 151 (5) ◽  
pp. 2233-2243 ◽  
Author(s):  
Kathryn Backholer ◽  
Jeremy T. Smith ◽  
Alix Rao ◽  
Alda Pereira ◽  
Javed Iqbal ◽  
...  
Keyword(s):  
Gene Expression ◽  
In Situ Hybridization ◽  
Neuropeptide Y ◽  
Preoptic Area ◽  
Cell Types ◽  
Normal Weight ◽  
Target Cells ◽  
Reciprocal Connections ◽  
Fluorescent Immunohistochemistry

Kisspeptin stimulates reproduction, and kisspeptin cells in the arcuate nucleus (ARC) express Ob-Rb in the mouse. Herein we report studies in ewes to determine whether kisspeptin cells express Ob-Rb and respond to leptin and whether reciprocal connections exist between kisspeptin cells and proopiomelanocortin (POMC) or neuropeptide Y (NPY) cells to modulate reproduction and metabolic function. Kiss1 mRNA was measured by in situ hybridization in ovariectomized ewes that were normal body weight, lean, or lean with leptin treatment by intracerebroventricular (icv) infusion (4 μg/h, 3 d). Kiss1 expression in the ARC and the preoptic area was lower in hypogonadotropic lean animals than animals of normal weight, and icv infusion of leptin partially restored Kiss1 expression in lean animals. Single-cell laser capture microdissection coupled with real-time PCR showed that Kiss1 cells in the preoptic area and ARC express Ob-Rb. Double-label fluorescent immunohistochemistry showed that reciprocal connections exist between kisspeptin cells and NPY and POMC cells. Accordingly, we treated ovariectomized ewes with kisspeptin (5 μg/h, icv) or vehicle for 20 h and examined POMC and NPY gene expression by in situ hybridization. Kisspeptin treatment reduced POMC and increased NPY gene expression. Thus, kisspeptin neurons respond to leptin and expression of Kiss1 mRNA is affected by leptin status. Kisspeptin cells communicate with NPY and POMC cells, altering expression of the relevant genes in the target cells; reciprocal connections also exist. This network between the three cell types could coordinate brain control of reproduction and metabolic homeostatic systems.

scholarly journals Hypothalamic Cocaine- and Amphetamine-Regulated Transcript (CART) and Agouti-Related Protein (AgRP) Neurons Coexpress the NOP1 Receptor and Nociceptin Alters CART and AgRP Release

Endocrinology ◽  
2005 ◽  
Vol 146 (8) ◽  
pp. 3526-3534 ◽  
Author(s):  
Gavin A. Bewick ◽  
Waljit S. Dhillo ◽  
Sarah J. Darch ◽  
Kevin G. Murphy ◽  
James V. Gardiner ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Food Intake ◽  
Energy Homeostasis ◽  
Ex Vivo ◽  
Zona Incerta ◽  
Related Protein ◽  
Orphanin Fq ◽  
Anatomical Basis ◽  
Agouti Related Protein

Abstract Nociceptin or orphanin FQ (N/OFQ) and its receptor NOP1 are expressed in hypothalamic nuclei involved in energy homeostasis. N/OFQ administered by intracerebroventricular or arcuate nucleus (ARC) injection increases food intake in satiated rats. The mechanisms by which N/OFQ increases food intake are unknown. We hypothesized that N/OFQ may regulate hypothalamic neurons containing peptides involved in the control of food intake such as cocaine- and amphetamine-regulated transcript (CART), αMSH, neuropeptide Y (NPY), and agouti-related protein (AgRP). We investigated the ability of N/OFQ to alter the release of CART, αMSH, NPY, and AgRP using ex vivo medial basal hypothalamic explants. Incubation of hypothalamic explants with N/OFQ (1, 10, 100 nm) resulted in significant changes in CART and AgRP release. One hundred nanomoles N/OFQ caused a 33% decrease in release of CART (55–102) immunoreactivity (IR) and increased release of AgRP-IR to 163% but produced no change in either αMSH-IR or NPY-IR. Double immunocytochemistry/in situ hybridization demonstrated that CART-IR and NOP1 mRNA are colocalized throughout the hypothalamus, in particular in the paraventricular nucleus, lateral hypothalamus, zona incerta, and ARC, providing an anatomical basis for N/OFQ action on CART release. Dual in situ hybridization demonstrated that AgRP neurons in the ARC also express the NOP1 receptor. Our data suggest that nociceptin via the NOP1 receptor may increase food intake by decreasing the release of the anorectic peptide CART and increasing the release of the orexigenic peptide AgRP.

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