In the face of constantly changing environments, the central nervous system (CNS) rapidly and accurately calculates the body's needs, regulates feeding behavior, and maintains energy homeostasis. The arcuate nucleus of the hypothalamus (ARC) plays a key role in this process, serving as a critical brain region for detecting nutrition-related hormones and regulating appetite and energy homeostasis. Agouti-related protein (AgRP)/neuropeptide Y (NPY) neurons in the ARC are core elements that interact with other brain regions through a complex appetite-regulating network to comprehensively control energy homeostasis. In this review, we explore the discovery and research progress of AgRP neurons in regulating feeding and energy metabolism. In addition, recent advances in terms of feeding behavior and energy homeostasis, along with the redundant neural mechanisms involved in energy metabolism, are discussed. Finally, the challenges and opportunities in the field of neural regulation of feeding and energy metabolism are briefly discussed.
Energy Metabolism/physiology* ; Animals ; Humans ; Hypothalamus/metabolism* ; Neurons/metabolism* ; Feeding Behavior/physiology* ; Brain Stem/metabolism* ; Agouti-Related Protein/metabolism* ; Homeostasis/physiology* ; Neuropeptide Y/metabolism*

Inhibitory GABAergic interneurons are fundamental elements of cortical circuits and play critical roles in shaping network activity. Dysfunction of interneurons can lead to various brain disorders, including epilepsy, schizophrenia, and anxiety. Based on the electrophysiological properties, cell morphology, and molecular identity, interneurons could be classified into various subgroups. In this study, we investigated the density and laminar distribution of different interneuron types and the co-expression of molecular markers in epileptic human cortex. We found that parvalbumin (PV) and somatostatin (SST) neurons were distributed in all cortical layers except layer I, while tyrosine hydroxylase (TH) and neuropeptide Y (NPY) were abundant in the deep layers and white matter. Cholecystokinin (CCK) neurons showed a high density in layers IV and VI. Neurons with these markers constituted ~7.2% (PV), 2.6% (SST), 0.5% (TH), 0.5% (NPY), and 4.4% (CCK) of the gray-matter neuron population. Double- and triple-labeling revealed that NPY neurons were also SST-immunoreactive (97.7%), and TH neurons were more likely to express SST (34.2%) than PV (14.6%). A subpopulation of CCK neurons (28.0%) also expressed PV, but none contained SST. Together, these results revealed the density and distribution patterns of different interneuron populations and the overlap between molecular markers in epileptic human cortex.
Adolescent ; Adult ; Brain Chemistry ; genetics ; physiology ; Cerebral Cortex ; metabolism ; pathology ; Child ; Cholecystokinin ; metabolism ; Epilepsy ; etiology ; pathology ; Female ; Gene Expression Regulation ; physiology ; Humans ; Interneurons ; metabolism ; Male ; Middle Aged ; Neuropeptide Y ; metabolism ; Parvalbumins ; metabolism ; Phosphopyruvate Hydratase ; metabolism ; Somatostatin ; metabolism ; Tyrosine 3-Monooxygenase ; metabolism ; Young Adult

To study the expression and distribution of neuropeptide Y (NPY) and long leptin receptor (OB-Rb) in the gastrointestinal tract of giant panda, samples of three animals were collected from the key laboratory for reproduction and conservation genetics of endangered wildlife of Sichuan province, China conservation and research center for the giant panda. Paraffin sections of giant panda gastrointestinal tissue samples were observed using hematoxylin-eosin staining (HE) and strept actividin-biotin complex immunohistochemical staining (IHC). The results show that the intestinal histology of three pandas was normal and no pathological changes, and there were rich single-cell and multi-cell mucous glands, long intestinal villi and thick muscularis mucosa and muscle layer. Positive cells expressing NPY and OB-Rb were widely detected in the gastrointestinal tract by IHC methods. NPY positive nerve fibers and neuronal cell were widely distributed in submucosal plexus and myenteric plexus, especially in the former. They were arranged beaded or point-like shape. NPY positive cells were observed in the shape of ellipse and polygon and mainly located in the mucous layer and intestinal glands. OB-Rb positive cells were mainly distributed in the mucous layer and the laminae propria, especially the latter. These results confirmed that NPY and OB-Rb are widely distributed in the gut of the giant panda, which provide strong reference for the research between growth and development, digestion and absorption, and immune function.
Animals ; China ; Intestines ; metabolism ; Neuropeptide Y ; genetics ; metabolism ; Receptors, Leptin ; genetics ; metabolism ; Ursidae ; genetics ; metabolism

5-hydroxytryptamine (5-HT) released in inflammatory tissues plays a pivotal role in pain hypersensitivity. However, it is not clear whether 5-HT2A receptors in the inflamed tissues mediate this effect. The present study investigated the contribution of 5-HT2A receptors in the periphery to chronic inflammatory pain. Complete Freund's adjuvant (CFA) was injected subcutaneously in the hindpaw of rats. The selective 5-HT2A receptor antagonist ketanserin was given in the inflamed site. Paw withdrawal latency responding to heat or mechanical stimuli was measured. Expression of neuropeptide Y (NPY) in the spinal dorsal horn and dorsal root ganglia (DRG) was assayed using immunohistochemistry technique. The results showed that ketanserin administered in the inflamed site inhibited thermal hyperalgesia in a dose-dependent manner (20, 40 and 80 µg) induced by the intraplantar injection of CFA. Ketanserin given once per day at a dose of 80 µg abolished heat hyperalgesia and also attenuated mechanical allodynia on the third day. CFA injection increased the expression of NPY in superficial laminae of the spinal cord, but not in the DRG. The local treatment of ketanserin completely inhibited CFA-induced increase in NPY expression in superficial laminae of the spinal cord. These results indicated that activation of 5-HT2A receptors in the inflamed tissues was involved in the pathogenesis of inflammatory pain and the blockade of 5-HT2A receptors in the periphery could relieve pain hypersensitivity and normalize the cellular disorder in the spinal dorsal horn associated with pathological pain. The present study suggests that the peripheral 5-HT2A receptors can be a promising target for pharmaceutical therapy to treat chronic inflammatory pain without central nervous system side effects.
Animals ; Freund's Adjuvant ; adverse effects ; Ganglia, Spinal ; metabolism ; Hot Temperature ; Hyperalgesia ; chemically induced ; drug therapy ; Inflammation ; drug therapy ; Ketanserin ; pharmacology ; Neuropeptide Y ; metabolism ; Pain ; drug therapy ; Pain Measurement ; Rats ; Receptor, Serotonin, 5-HT2A ; metabolism ; Serotonin ; Serotonin 5-HT2 Receptor Antagonists ; pharmacology ; Spinal Cord Dorsal Horn ; metabolism

OBJECTIVETo investigate the density and distribution of nerve endings and neuropeptide Y (NPY) in lumbar facet joints of patients with low back pain.

METHODSFifteen patients without low back pain were selected as control group (group A). Facet joint samples in group A were obtained during the operation or lumbar spinal canal tumor they suffered from. Those patients with low back pain were divided into three groups according to their different origins of pain, such as not from facet joint (group B, 15 patients) ,from facet joint only (group C, 20 patients), or from facet joint partially (group D, 20 patients). Different origins were determined by VAS after facet joint block. The density and distribution of nerve ending and neuropeptide in the capsular tissues were analyzed by a modified gold chloride staining and immunochemistry respectively.

RESULTSCompared with the ones in group A and B, the fact joints in group C and D were more inclined to be degenerated and got more nerve endings. NPY was expressed mainly in the facet joint of patients with low back pain in group C and D. In addition, there was a significant relationship between the distribution of nerve endings and NPY expression,while none of them were related with MRI Fujiwara grade of facet joint.

CONCLUSIONThese results suggest that the number of mechanoreceptors, neural sprouting and secreted peptides in the facet joint capsules vary with the change of mechanical or nociceptive stimulation, which may promote the development of low back pain in return.

Adult ; Aged ; Case-Control Studies ; Chronic Pain ; etiology ; metabolism ; pathology ; Female ; Humans ; Low Back Pain ; etiology ; metabolism ; pathology ; Male ; Mechanoreceptors ; physiology ; Middle Aged ; Nerve Endings ; pathology ; Neuropeptide Y ; analysis

OBJECTIVETo study the leptin resistance mechanism of Xiaoyan Decoction (XD) in lung cancer cachexia (LCC) rats.

METHODSAn LCC rat model was established. Totally 40 rats were randomly divided into the normal control group, the LCC model group, the XD group, and the positive control group, 10 in each group. After LCC model was set up, rats in the LCC model group were administered with normal saline, 2 mL each time. Rats in the XD group were administered with XD at the daily dose of 2 mL. Those in the positive control group were administered with Medroxyprogesterone Acetate suspension (20 mg/kg) by gastrogavage at the daily dose of 2 mL. All medication lasted for 14 days. The general condition and tumor growth were observed. Serum levels of leptin and leptin receptor in the hypothalamus were detected using enzyme-linked immunosorbent assay. Contents of neuropeptide Y (NPY) and anorexia for genomic POMC were detected using real-time PCR technique.

RESULTSSerum leptin levels were lower in the LCC model group than in the normal control group with statistical significance (P < 0.05). Compared with the LCC model groups, serum leptin levels significantly increased in the XD group (P < 0.01). Leptin receptor levels in the hypothalamus increased significantly in the LCC model group (P < 0.01). Increased receptor levels in the LCC model group indicated that either XD or Medroxyprogesterone Acetate could effectively reduce levels of leptin receptor with statistical significance (P < 0.01). There was also statistical difference between the XD group and the positive control group (P < 0.05). Contents of NPY was higher in the LCC model group than in the other groups with statistical difference (P < 0.05). There was no statistical difference in NPY between the normal control group and the rest 2 treatment groups (P > 0.05). There was statistical difference in POMC between the normal control group and the LCC model group (P < 0.05). POMC could be decreased in the XD group and the positive control group with statistical significance (P < 0.05), and it was more obviously decreased in the XD group (P < 0.05).

CONCLUSIONSLeptin resistance existed in LCC rats. XD could increase serum leptin levels and reduce leptin receptor levels in the hypothalamus. LCC could be improved by elevating NPY contents in the hypothalamus and reducing POMC contents, promoting the appetite, and increasing food intake from the periphery pathway and the central pathway.

Animals ; Cachexia ; drug therapy ; etiology ; Drugs, Chinese Herbal ; therapeutic use ; Eating ; Humans ; Hypothalamus ; metabolism ; Leptin ; metabolism ; Lung Neoplasms ; complications ; Neuropeptide Y ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To investigate the expression pattern of adapter protein with a Src-homology 2 domain (SH2B1), the suppressor of cytokine signaling-3 (SOCS3), protein-tyrosine phosphatase 1B (PTP1B) and neturopetide Y (NPY) in obese and normal mice hypothalamus and its relation with serum leptin and insulin levels. METHODS: The obesity animal model was prepared with healthy C57/bl6 mice. Lee's index and Homeostasis model assessment-insulin resistance (HOMA-IR) were calculated. The mRNA levels of SH2B1, SOCS3, PTP1B and NPY were measured by fluorescent quantitation RT-PCR. The SH2B1 and NPY protein expressions were detected by Western blot. RESULTS: Compared with the normal mice of the same age, SH2B1 mRNA expression in the obese mice hypothalamus decreased. SOCS3 and PTP1B mRNA expression increased. Western blot showed that SH2B1 protein expression decreased, while NPY protein expression increased in the obese mice. Linear correlation analysis showed that the serum leptin and fasting insulin levels were negatively correlated with SH2B1mRNA expression and positively correlated with SOCS3 and PTP1B mRNA expression. CONCLUSION SH2B1, SOCS3, PTP1B and NPY are key factors for obesity development.
Adaptor Proteins, Signal Transducing ; metabolism ; Animals ; Hypothalamus ; metabolism ; Insulin ; blood ; Insulin Resistance ; Leptin ; blood ; Mice ; Mice, Inbred C57BL ; Neuropeptide Y ; metabolism ; Obesity ; metabolism ; Protein Tyrosine Phosphatase, Non-Receptor Type 1 ; metabolism ; RNA, Messenger ; Suppressor of Cytokine Signaling 3 Protein ; Suppressor of Cytokine Signaling Proteins ; metabolism

OBJECTIVETo explore the effect of Changji'an Capsule (CA) on mRNA expressions of neuropeptide Y (NPY) in the hypothalamus and colon and serum levels of adreno-cortico-tropic hormone (ACTH) in rats of diarrhea predominant irritable bowel syndrome (IBS-D) model rats.

METHODSTotally 48 SD rats were randomly divided into six groups, i.e., the normal control group, the model group, the Pinaverium Bromide group (PB, 0.018 g/kg), the high dose CA group (2.812 g/kg), the medium dose CA group (1.406 g/kg), and the low dose CA group (0.703 g/kg), 8 in each group. The IBS-D rat model was established by using separation of breast milk + stimulation of acetic acid + constraint of four limbs. Normal saline was given to rats in the normal control group and the model group. All medication lasted for 14 successive days by gastrogavage. The serum content of ACTH was detected by enzyme linked immunosorbent assay (ELISA). The expressions of NPY mRNA in the colon and the hypothalamus were detected using real-time fluorescence quantitative PCR.

RESULTSCompared with the normal control group, the serum ACTH content significantly increased (P < 0.01), the NPY mRNA expression in the colon and the hypothalamus obviously decreased (P < 0.01) in the model control group. Compared with the model group, the serum ACTH obviously decreased in the high dose CA group, the medium dose CA group, and the PB group (P < 0.01, P < 0.05). The NPY mRNA expression in the colon and the hypothalamus were obviously up-regulated in the high dose CA group, the medium dose CA group, the low dose CA group, and the PB group (P < 0.05).

CONCLUSIONSCA could modulate the abnormity of brain-gut axis of IBS-D rats possibly by up-regulating NPY mRNA expressions in the hypothalamus and the colon and down-regulating the ACTH content in the hypothalamic-pituitary-adrenal axis.

Adrenocorticotropic Hormone ; blood ; Animals ; Colon ; metabolism ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Female ; Hypothalamus ; metabolism ; Irritable Bowel Syndrome ; metabolism ; Male ; Neuropeptide Y ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effects of gestational isoflurane exposure on postnatal memory and learning and growth-associated protein-43 (GAP-43), neuropeptide Y(NPY) expression in the hippocampus of pups.

METHODSTwelve maternal Sprague-Dawley rats at gestation d 18(E18) were randomly divided into isoflurane group (n=6) and control group (n=6). Rats in isoflurane group were exposed to 1.3 % isoflurane for 6 h. For control group, animals breathed in 30 % oxygen and air mixed gas at the same condition. Spatial learning and memory of the offspring were determined with the Morris Water Maze(MWM) after postnatal 4 weeks. The changes of GAP-43 and NPY expression in the hippocampal CA1 region of the pups were determined by immunohistochemistry.

RESULTSIn MWM training, the escape latency to platform of the pups in isoflurane group was significantly longer, and the time spent in the third quadrant and times of original platform crossing were less than those of control animals (P<0.05). The number and optical density of GAP-43 and NPY positive neurons in the hippocampus of pups decreased significantly in the isoflurane group compared with the controls (P <0.01).

CONCLUSIONIsoflurane exposure in pregnant rats significantly impairs the spatial memory and learning of their pups at a juvenile age, which may be associated with the down-regulation of GAP-43 and NPY in the hippocampus.

Animals ; Female ; GAP-43 Protein ; metabolism ; Hippocampus ; drug effects ; metabolism ; Isoflurane ; pharmacology ; Maze Learning ; drug effects ; Neuropeptide Y ; metabolism ; Pregnancy ; Prenatal Exposure Delayed Effects ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo compare the regulatory effects of electro-acupuncture (EA) at acupoints Zusanli (ST36) and Hegu (LI4) on the visceral hyper-sensitivity in the rat model of irritable bowel syndrome (IBS), and to explore the acting targets and specialty of acupoints.

METHODSExcept 8 rats of the normal control group, the rest 32 rats were prepared to set up the IBS models. IBS animal model was prepared by enema with acetic acid. Model rats were divided into three groups. Except for rats in the model group for control, those in the other two groups were treated 20 min by EA on ST36 (EA-ST36) and LI4 (EA-LI4) respectively for 2 weeks to observe the effect on behavior response of viscera sensitivity. The changes of neuropeptide (NPY), the somatostatin (SS) levels in blood and tissues of brain and intestine were monitored as well.

RESULTSThe volume thresholds for abdomen uplifting and back hunching were obviously increased after EA-ST36 (P<0.05), but showed insignificant change after EA-LI4. NPY contents lowered and SS contents increased in model rats; both EA-ST36 and EA-LI4 could raise the level of thalamic NPY (P<0.01 and P<0.05, respectively), but showed insignificant effects on NPY in colonic tissue. As for SS content, its colonic level could be reduced by EA-S36 and EA-LI4 (P<0.01 and P<0.05, respectively), however, its blood level was affected only by EA-ST36 (P<0.05).

CONCLUSIONSEA-ST36 or EA-LI4 could regulate the NPY in thalamus and SS in colonic tissue, the former could affect blood level of SS as well. It is deemed that NPY and SS may be the key substances for regulating the action of acupuncture in the brain-intestinal axis; their different levels could be regarded as an indicator for the functional difference between the acupoints.

Acupuncture Points ; Animals ; Brain ; metabolism ; Electroacupuncture ; methods ; Irritable Bowel Syndrome ; metabolism ; physiopathology ; Neuropeptide Y ; metabolism ; Rats ; Rats, Wistar ; Somatostatin ; metabolism ; Viscera ; physiopathology