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1.
Reprod Med Biol ; 23(1): e12570, 2024.
Article in English | MEDLINE | ID: mdl-38566911

ABSTRACT

Purpose: The pathophysiology of penis extends to erectile dysfunction (ED) to conditions including sexually transmitted diseases (STDs) and cancer. To date, there has been little research evaluating vascular drainage from the penis. We aimed to evaluate penile blood flow in vivo and analyze its possible relationship with the lymphatic maker. Materials and Methods: We established an in vivo system designed to assess the dynamic blood outflow from the corpus cavernosum (CC) by dye injection. To analyze lymphatic characteristics in the CC, the expression of Lyve-1, the key lymphatic endothelium marker, was examined by the in vitro system and lipopolysaccharide (LPS) injection to mimic the inflammatory conditions. Results: A novel cavernography methods enable high-resolution morphological and functional blood drainage analysis. The expression of Lyve-1 was detected along the sinusoids. Furthermore, its prominent expression was also observed after penile LPS injection and in the erectile condition. Conclusions: The current in vivo system will potentially contribute to the assessment of penile pathology from a novel viewpoint. In addition, current analyses revealed inducible Lyve-1 expression for LPS injection and the erection state, which requires further analyses on penile lymphatic system.

2.
Reprod Med Biol ; 22(1): e12539, 2023.
Article in English | MEDLINE | ID: mdl-37663955

ABSTRACT

Background: The corpus cavernosum (CC) containing sinusoids plays fundamental roles for erection. Analysis of pathological changes in the erectile system is studied by recent experimental systems. Various in vitro models utilizing genital mesenchymal-derived cells and explant culture systems are summarized. Methods: 3D reconstruction of section images of murine CC was created. Ectopic chondrogenesis in aged mouse CC was shown by a gene expression study revealing the prominent expression of Sox9. Various experimental strategies utilizing mesenchyme-derived primary cells and tissue explants are introduced. Main Findings: Possible roles of Sox9 in chondrogenesis and its regulation by several signals are suggested. The unique character of genital mesenchyme is shown by various analyses of external genitalia (ExG) derived cells and explant cultures. Such strategies are also applied to the analysis of erectile contraction/relaxation responses to many signals and aging process. Conclusion: Erectile dysfunction (ED) is one of the essential topics for the modern aged society. More comprehensive studies are necessary to reveal the nature of the erectile system by combining multiple cell culture strategies.

3.
Int J Mol Sci ; 24(9)2023 May 04.
Article in English | MEDLINE | ID: mdl-37175953

ABSTRACT

1,5-Anhydro-D-fructose (1,5-AF) is a bioactive monosaccharide that is produced by the glycogenolysis in mammalians and is metabolized to 1,5-anhydro-D-glucitol (1,5-AG). 1,5-AG is used as a marker of glycemic control in diabetes patients. 1,5-AF has a variety of physiological activities, but its effects on energy metabolism, including feeding behavior, are unclarified. The present study examined whether 1,5-AF possesses the effect of satiety. Peroral administration of 1,5-AF, and not of 1,5-AG, suppressed daily food intake. Intracerebroventricular (ICV) administration of 1,5-AF also suppressed feeding. To investigate the neurons targeted by 1,5-AF, we investigated c-Fos expression in the hypothalamus and brain stem. ICV injection of 1,5-AF significantly increased c-Fos positive oxytocin neurons and mRNA expression of oxytocin in the paraventricular nucleus (PVN). Moreover, 1,5-AF increased cytosolic Ca2+ concentration of oxytocin neurons in the PVN. Furthermore, the satiety effect of 1,5-AF was abolished in oxytocin knockout mice. These findings reveal that 1,5-AF activates PVN oxytocin neurons to suppress feeding, indicating its potential as the energy storage monitoring messenger to the hypothalamus for integrative regulation of energy metabolism.


Subject(s)
Oxytocin , Paraventricular Hypothalamic Nucleus , Mice , Animals , Paraventricular Hypothalamic Nucleus/metabolism , Oxytocin/metabolism , Hypothalamus/metabolism , Neurons/metabolism , Mammals/metabolism
4.
Sci Rep ; 13(1): 2150, 2023 02 07.
Article in English | MEDLINE | ID: mdl-36750743

ABSTRACT

Ghrelin, an orexigenic peptide ligand for growth hormone secretagogue receptor 1a (GHS-R1a), occurs not only in the stomach but also in the brain, and modulates neuronal activity and synaptic efficacy. Previous studies showed that GHS-R1a exists in the cerebellum, and ghrelin facilitates spontaneous firing of Purkinje cells (PCs). However, the effects of ghrelin on cerebellar GABAergic transmission have yet to be elucidated. We found that ghrelin enhanced GABAergic transmission between molecular layer interneurons (MLIs) and PCs using electrophysiological recordings in mouse cerebellar slices. This finding was consistent with the possibility that blocking synaptic transmission enhanced the ghrelin-induced facilitation of PC firing. Ghrelin profoundly increased the frequency of spontaneous inhibitory postsynaptic currents (IPSCs) in PCs without affecting miniature or stimulation-evoked IPSCs, whereas it significantly facilitated spontaneous firing of MLIs. This facilitation of MLI spiking disappeared during treatments with blockers of GHS-R1a, type 1 transient receptor potential canonical (TRPC1) channels and KCNQ channels. These results suggest that both activating TRPC1 channels and inhibiting KCNQ channels occur downstream the ghrelin-GHS-R1a signaling pathway probably in somatodendritic sites of MLIs. Thus, ghrelin can control PC firing directly and indirectly via its modulation of GABAergic transmission, thereby impacting activity in cerebellar circuitry.


Subject(s)
Ghrelin , Purkinje Cells , Animals , Mice , Cerebellar Cortex/metabolism , Ghrelin/metabolism , Purkinje Cells/metabolism , Receptors, Ghrelin/metabolism , Signal Transduction , gamma-Aminobutyric Acid/metabolism
5.
Nutrients ; 14(13)2022 Jun 23.
Article in English | MEDLINE | ID: mdl-35807782

ABSTRACT

The central melanocortin system conducted by anorexigenic pro-opiomelanocortin (POMC) neurons and orexigenic agouti-related peptide (AgRP) neurons in the arcuate nucleus of the hypothalamus (ARC) not only regulates feeding behavior but also blood pressure. Excessive salt intake raises the Na+ concentration ([Na+]) in the cerebrospinal fluid (CSF) and worsens hypertension. The blood-brain barrier is immature in the ARC. Therefore, both AgRP and POMC neurons in the ARC have easy access to the electrolytes in the blood and can sense changes in their concentrations. However, the sensitivity of AgRP and POMC neurons to Na+ remains unclear. This study aimed to explore how the changes in the extracellular Na+ concentration ([Na+]) influence these neurons by measuring the cytosolic Ca2+ concentration ([Ca2+]i) in the single neurons isolated from the ARC that were subsequently immunocytochemically identified as AgRP or POMC neurons. Both AgRP and POMC neurons responded to increases in both [Na+] and osmolarity in C57BL/6 mice. In contrast, in transient receptor potential vanilloid 1 (TRPV1) knockout (KO) mice, POMC neurons failed to respond to increases in both [Na+] and osmolarity, while they responded to high glucose and angiotensin II levels with increases in [Ca2+]i. Moreover, in KO mice fed a high-salt diet, the expression of POMC was lower than that in wild-type mice. These results demonstrate that changes in [Na+] and osmolarity are sensed by the ARC POMC neurons via the TRPV1-dependent mechanism.


Subject(s)
Arcuate Nucleus of Hypothalamus , Pro-Opiomelanocortin , Agouti-Related Protein/metabolism , Animals , Arcuate Nucleus of Hypothalamus/metabolism , Hypothalamus/metabolism , Mice , Mice, Inbred C57BL , Neurons/metabolism , Osmotic Pressure , Pro-Opiomelanocortin/metabolism , Sodium/metabolism , TRPV Cation Channels/genetics , TRPV Cation Channels/metabolism
6.
Neurosci Res ; 180: 48-57, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35218859

ABSTRACT

Despite the multiple regions and neural networks associated with value-based decision-making, the orbitofrontal cortex (OFC) is possible a particularly important one. Although the role of the OFC in reinforcer devaluation tasks, which assess the ability to represent identity, sensory qualities, and subjective values of the expected outcomes, has been established, the specific aspect represented in this area remains unclear. In this study, using functional magnetic resonance imaging, wherein participants rated the palatability of 128 food items using photographs, we investigated whether the human OFC represents object identity, sensory qualities, or value. Employing many items helped us dissociate object identity from sensory qualities and values; the inferred sensory qualities of identical items were manipulated by a change in metabolic state. Moreover, value differences between items were analytically controlled by employing a technique similar to age adjustment. The palatability ratings for food items significantly decreased after a meal. Using representational similarity analysis, we confirmed that the OFC represents value. Moreover, identical items were represented similarly in the lateral OFC in a given metabolic state; however, these representations were altered post-feeding. Importantly, this change was not explained by subjective value, suggesting that the OFC represents sensory quality and value, but not object identity.


Subject(s)
Prefrontal Cortex , Reward , Humans , Magnetic Resonance Imaging , Prefrontal Cortex/diagnostic imaging
7.
Nutrients ; 13(12)2021 Dec 15.
Article in English | MEDLINE | ID: mdl-34960038

ABSTRACT

It is suggested that clock genes link the circadian rhythm to glucose and lipid metabolism. In this study, we explored the role of the clock gene Bmal1 in the hypothalamic paraventricular nucleus (PVN) in glucose metabolism. The Sim1-Cre-mediated deletion of Bmal1 markedly reduced insulin secretion, resulting in impaired glucose tolerance. The pancreatic islets' responses to glucose, sulfonylureas (SUs) and arginine vasopressin (AVP) were well maintained. To specify the PVN neuron subpopulation targeted by Bmal1, the expression of neuropeptides was examined. In these knockout (KO) mice, the mRNA expression of Avp in the PVN was selectively decreased, and the plasma AVP concentration was also decreased. However, fasting suppressed Avp expression in both KO and Cre mice. These results demonstrate that PVN BMAL1 maintains Avp expression in the PVN and release to the circulation, possibly providing islet ß-cells with more AVP. This action helps enhance insulin release and, consequently, glucose tolerance. In contrast, the circadian variation of Avp expression is regulated by feeding, but not by PVN BMAL1.


Subject(s)
ARNTL Transcription Factors/metabolism , Circadian Clocks/physiology , Gene Expression Regulation/physiology , Glucose/metabolism , Paraventricular Hypothalamic Nucleus/physiology , ARNTL Transcription Factors/genetics , Animals , Arginine Vasopressin/genetics , Arginine Vasopressin/metabolism , Glucose Intolerance , Insulin/metabolism , Mice , Mice, Knockout , Neurons , RNA, Messenger/genetics , RNA, Messenger/metabolism
8.
Article in English | MEDLINE | ID: mdl-32733584

ABSTRACT

BACKGROUND: The aim of the present study was to assess the effects of lavender oil inhalation on blood pressure, pulse measurements, cortisol levels, depressive mood, and anxiety in healthy male adults. The mechanism was investigated by the action on oxytocin single neurons in the hypothalamus of rodents. METHODS: The participants (n = 7) were aged 20-40 years. After randomisation, they received an inhaled dose of lavender oil or distilled water for 20 min. They received the other treatment after a washout period of one week. We assessed the outcomes using the Self-Rating Depression Scale, State-Trait Anxiety Inventory, and self-rated unidimensional Visual Analogue Scale for depression; anxiety; and hunger, thirst, and appetite, respectively. Blood pressure, pulse rate, and cortisol concentration in the peripheral blood were assessed before and after inhalation. In the rodent study (n = 4), oxytocin single neurons were isolated from the mouse hypothalamus. Intracellular Ca2+ concentration in the oxytocin neurons isolated from the hypothalamus was measured following direct administration of lavender oil. RESULTS: Seven participants completed the study. Lavender inhalation decreased Self-Rating Depression Scale score and systolic and diastolic blood pressure. Ex vivo administration of lavender oil increased intracellular Ca2+ concentration in the hypothalamic oxytocin neurons. CONCLUSIONS: Lavender oil might be a useful therapy for stress relief, and its mechanism of action may include activation of the central oxytocin neurons.

9.
Int J Mol Sci ; 20(19)2019 Oct 08.
Article in English | MEDLINE | ID: mdl-31597354

ABSTRACT

Cardiac fibrosis is a major cause of cardiac dysfunction in hypertrophic hearts. Differentiated embryonic chondrocyte gene 1 (Dec1), a basic helix-loop-helix transcription factor, has circadian expression in the heart; however, its role in cardiac diseases remains unknown. Therefore, using Dec1 knock-out (Dec1KO) and wild-type (WT) mice, we evaluated cardiac function and morphology at one and four weeks after transverse aortic constriction (TAC) or sham surgery. We found that Dec1KO mice retained cardiac function until four weeks after TAC. Dec1KO mice also revealed more severely hypertrophic hearts than WT mice at four weeks after TAC, whereas no significant change was observed at one week. An increase in Dec1 expression was found in myocardial and stromal cells of TAC-treated WT mice. In addition, Dec1 circadian expression was disrupted in the heart of TAC-treated WT mice. Cardiac perivascular fibrosis was suppressed in TAC-treated Dec1KO mice, with positive immunostaining of S100 calcium binding protein A4 (S100A4), alpha smooth muscle actin (αSMA), transforming growth factor beta 1 (TGFß1), phosphorylation of Smad family member 3 (pSmad3), tumor necrosis factor alpha (TNFα), and cyclin-interacting protein 1 (p21). Furthermore, Dec1 expression was increased in myocardial hypertrophy and myocardial infarction of autopsy cases. Taken together, our results indicate that Dec1 deficiency suppresses cardiac fibrosis, preserving cardiac function in hypertrophic hearts. We suggest that Dec1 could be a new therapeutic target in cardiac fibrosis.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/deficiency , Cardiomyopathies/etiology , Cardiomyopathies/metabolism , Ventricular Outflow Obstruction/complications , Animals , Biomarkers , Cardiomegaly/diagnosis , Cardiomegaly/etiology , Cardiomegaly/metabolism , Cardiomyopathies/diagnosis , Disease Models, Animal , Echocardiography , Fibrosis , Gene Expression , Heart Function Tests , Homeodomain Proteins , Male , Mice , Mice, Knockout , Myocardial Infarction/diagnosis , Myocardial Infarction/etiology , Myocardial Infarction/metabolism , Ventricular Outflow Obstruction/diagnosis , Ventricular Remodeling
10.
Sci Rep ; 9(1): 12986, 2019 09 19.
Article in English | MEDLINE | ID: mdl-31537818

ABSTRACT

Glucagon-like peptide-1 receptor (GLP-1R) agonists, widely used to treat type 2 diabetes, reduce blood pressure (BP) in hypertensive patients. Whether this action involves central mechanisms is unknown. We here report that repeated lateral ventricular (LV) injection of GLP-1R agonist, liraglutide, once daily for 15 days counteracted the development of hypertension in spontaneously hypertensive rats (SHR). In parallel, it suppressed urinary norepinephrine excretion, and induced c-Fos expressions in the area postrema (AP) and nucleus tractus solitarius (NTS) of brainstem including the NTS neurons immunoreactive to dopamine beta-hydroxylase (DBH). Acute administration of liraglutide into fourth ventricle, the area with easy access to the AP and NTS, transiently decreased BP in SHR and this effect was attenuated after lesion of NTS DBH neurons with anti-DBH conjugated to saporin (anti-DBH-SAP). In anti-DBH-SAP injected SHR, the antihypertensive effect of repeated LV injection of liraglutide for 14 days was also attenuated. These findings demonstrate that the central GLP-1R signaling via NTS DBH neurons counteracts the development of hypertension in SHR, accompanied by attenuated sympathetic nerve activity.


Subject(s)
Brain Stem/metabolism , Dopaminergic Neurons/metabolism , Glucagon-Like Peptide-1 Receptor/metabolism , Hypertension/metabolism , Signal Transduction , Animals , Brain Stem/pathology , Dopamine beta-Hydroxylase/metabolism , Dopaminergic Neurons/pathology , Glucagon-Like Peptide-1 Receptor/agonists , Hypertension/chemically induced , Hypertension/pathology , Liraglutide/adverse effects , Liraglutide/pharmacology , Male , Rats , Rats, Inbred SHR , Rats, Inbred WKY
11.
J Physiol Sci ; 69(5): 733-739, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31228099

ABSTRACT

Nesfatin-1 is a hypothalamic anorexigenic peptide processed from nucleobindin 2 (NUCB2). Central and peripheral administration of NUCB2/nesfatin-1 enhances glucose metabolism and insulin release. NUCB2/nesfatin-1 is also localized in pancreatic islets, while its function remains unknown. To explore the role of pancreatic ß-cell-produced NUCB2/nesfatin-1, we developed pancreatic ß-cell-specific NUCB2 knockout (ßNUCB2 KO) mice and NUCB2 gene knockdown (shNUCB2) MIN6 ß-cell line. In ßNUCB2 KO mice, casual blood glucose was elevated from 12 weeks of age. In a glucose tolerance test at 12 weeks, insulin secretion at 15 min was reduced and blood glucose at 2 h increased in ßNUCB2 KO mice fasted 8 h. In islets isolated from ßNUCB2 KO mice, high glucose-stimulated insulin secretion (GSIS) was impaired. In shNUCB2 MIN6 cells, GSIS was reduced and UCP-2 mRNA expression was elevated. These results show impaired GSIS possibly associated with UCP-2 overexpression in NUCB2-silenced ß-cells, suggesting that ß-cell-produced NUCB2/nesfatin-1 maintains GSIS and thereby glycemia.


Subject(s)
Blood Glucose/metabolism , Glycemic Index/physiology , Insulin Secretion/physiology , Insulin-Secreting Cells/metabolism , Insulin/metabolism , Nucleobindins/metabolism , Uncoupling Protein 2/metabolism , Animals , Cell Line , Glucose/metabolism , Glucose Tolerance Test/methods , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Rats
12.
J Cardiol Cases ; 18(1): 33-36, 2018 Jul.
Article in English | MEDLINE | ID: mdl-30279906

ABSTRACT

Left ventricular noncompaction (LVNC) is a distinct cardiomyopathy that is morphologically characterized by a two-layered myocardium, numerous prominent trabeculations, and deep intertrabecular recesses communicating with the left ventricular cavity. We present a case report regarding the identification of a new mutation in TNNI3 in a patient with LVNC using next-generation sequencing. A 13-year-old girl who had no family history of cardiac disease was hospitalized with dyspnea after exercise and electrocardiographic abnormalities during a school screening. Based on her clinical features, she was diagnosed with LVNC. Via genetic analysis, a TNNI3 heterozygous missense variant was identified in the proband. Although mutations in TNNI3 have been reported in patients with hypertrophic cardiomyopathy and restrictive cardiomyopathy, this is the first report of a mutation in this gene in a patient with LVNC. .

13.
Sci Rep ; 8(1): 10415, 2018 Jul 10.
Article in English | MEDLINE | ID: mdl-29991705

ABSTRACT

Oxytocin neurons in the paraventricular nucleus (PVN) of hypothalamus regulate energy metabolism and reproduction. Plasma oxytocin concentration is reduced in obese subjects with insulin resistance. These findings prompted us to hypothesize that insulin serves to promote oxytocin release. This study examined whether insulin activates oxytocin neurons in the PVN, and explored the underlying signaling. We generated the mice deficient of 3-phosphoinositide-dependent protein kinase-1 (PDK1), a major signaling molecule particularly for insulin, specifically in oxytocin neurons (Oxy Pdk1 KO). Insulin increased cytosolic calcium concentration ([Ca2+]i) in oxytocin neurons with larger (≧25 µm) and smaller (<25 µm) diameters isolated from PVN in C57BL/6 mice. In PDK1 Oxy Pdk1 KO mice, in contrast, this effect of insulin to increase [Ca2+]i was markedly diminished in the larger-sized oxytocin neurons, while it was intact in the smaller-sized oxytocin neurons. Furthermore, intracerebroventricular insulin administration induced oxytocin release into plasma in Oxy Cre but not Oxy Pdk1 KO mice. These results demonstrate that insulin PDK1-dependently preferentially activates PVN magnocellular oxytocin neurons to release oxytocin into circulation, possibly serving as a mechanism for the interaction between metabolism and perinatal functions.


Subject(s)
3-Phosphoinositide-Dependent Protein Kinases/genetics , Energy Metabolism/genetics , Insulin/administration & dosage , Oxytocin/genetics , Animals , Calcium Signaling/genetics , Hypothalamus/metabolism , Insulin/blood , Mice , Mice, Knockout , Neurons/metabolism , Oxytocin/blood , Paraventricular Hypothalamic Nucleus/metabolism
14.
Biochem Biophys Res Commun ; 500(4): 910-916, 2018 06 12.
Article in English | MEDLINE | ID: mdl-29705701

ABSTRACT

In the hypothalamic arcuate nucleus (ARC), orexigenic agouti-related peptide (AgRP) neurons regulate feeding behavior and energy homeostasis. The 3-phosphoinositide-dependent protein kinase-1 (PDK1) in AgRP neurons serves as a major signaling molecule for leptin and insulin, the hormones regulating feeding behavior, energy homeostasis and circulation. However, it is unclear whether PDK1 in AGRP neurons is also involved in regulation of blood pressure. This study explored it by generating and analyzing AgRP neuron-specific PDK1 knockout (Agrp-Pdk1flox/flox) mice and effect of high salt diet on blood pressure in KO and WT mice was analyzed. Under high salt diet feeding, systolic blood pressure (SBP) of Agrp-Pdk1flox/flox mice was significantly elevated compared to Agrp-Cre mice. When the high salt diet was switched to control low salt diet, SBP of Agrp-Pdk1flox/flox mice returned to the basal level observed in Agrp-Cre mice within 1 week. In Agrp-Pdk1flox/flox mice, urinary noradrenalin excretion and NUCB2 mRNA expression in hypothalamic paraventricular nucleus (PVN) were markedly upregulated. Moreover, silencing of NUCB2 in the PVN counteracted the rises in urinary noradrenalin excretions and SBP. These results demonstrate a novel role of PDK1 in AgRP neurons to counteract the high salt diet-induced hypertension by preventing hyperactivation of PVN nesfatin-1 neurons.


Subject(s)
Agouti-Related Protein/genetics , Arcuate Nucleus of Hypothalamus/metabolism , Hypertension/genetics , Neurons/metabolism , Paraventricular Hypothalamic Nucleus/metabolism , Protein Serine-Threonine Kinases/genetics , Agouti-Related Protein/deficiency , Animals , Arcuate Nucleus of Hypothalamus/drug effects , Arcuate Nucleus of Hypothalamus/physiopathology , Blood Pressure , Calcium-Binding Proteins/genetics , Calcium-Binding Proteins/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Disease Models, Animal , Energy Intake/drug effects , Feeding Behavior/drug effects , Gene Expression Regulation , Hypertension/chemically induced , Hypertension/metabolism , Hypertension/physiopathology , Insulin/genetics , Insulin/metabolism , Leptin/genetics , Leptin/metabolism , Mice , Mice, Knockout , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Neurons/drug effects , Neurons/pathology , Norepinephrine/urine , Nucleobindins , Paraventricular Hypothalamic Nucleus/drug effects , Paraventricular Hypothalamic Nucleus/physiopathology , Protein Serine-Threonine Kinases/deficiency , Pyruvate Dehydrogenase Acetyl-Transferring Kinase , RNA, Messenger/genetics , RNA, Messenger/metabolism , Signal Transduction , Sodium Chloride, Dietary/adverse effects
15.
Biochem Biophys Res Commun ; 499(3): 618-625, 2018 05 15.
Article in English | MEDLINE | ID: mdl-29601817

ABSTRACT

Endogenous GLP-1 and GLP-1 receptor agonists (GLP-1RAs) regulate glucose metabolism via common and distinct mechanisms. Postprandial release of GLP-1 is modest and it is degraded by DPP-4 within 2 min, and hence it cannot enter the brain in substantial amount. In contrast, DPP-4-resistant GLP-1RAs are administered at 10 times higher concentration than endogenous GLP-1 level, which enables them to reach several brain regions including ARC and AP, the areas implicated in glucose metabolism. Hence, some of the effects of GLP-1RAs observed clinically and experimentally, including pancreatic ß-cell proliferation, are thought to involve the brain. However, the effects of centrally acting GLP-1/GLP-1RAs on glucose metabolism and underlying neural mechanism are unclear. This study aimed to establish the link of central GLP-1/GLP-1RA action to pancreatic ß-cell proliferation. Both subcutaneous (SC) and intracerebroventricular (ICV) injections of liraglutide increased the number of pancreatic ß-cells expressing Ki67 and PCNA, proliferation markers, in C57BL/6J mice. This effect was induced by single ICV administration of liraglutide at relatively low dose that was incapable of suppressing food intake. These SC and ICV liraglutide-induced effects were inhibited by 50% and 70%, respectively, by pretreatment with atropine, a muscarinic receptor blocker. ICV liraglutide induced c-Fos expression in the area postrema (AP), nucleus tractus solitaries (NTS), and dorsal motor nucleus of the vagus (DMX) of the brain stem. These results demonstrate that central action of liraglutide induces pancreatic ß-cell proliferation via the pathway involving the brain stem AP/NTS/DMX area and vagus nerve. This route is highly sensitive to GLP-1/GLP-1RA. Hence, this brain-pancreatic ß-cell pathway may operate in type 2 diabetic patients treated with GLP-RAs and serve to counteract the reduction of ß-cell mass.


Subject(s)
Glucagon-Like Peptide-1 Receptor/agonists , Insulin-Secreting Cells/cytology , Liraglutide/pharmacology , Medulla Oblongata/metabolism , Vagus Nerve/metabolism , Animals , Atropine/pharmacology , Brain Stem/drug effects , Brain Stem/metabolism , Cell Proliferation/drug effects , Feeding Behavior , Glucagon-Like Peptide 1/pharmacology , Glucagon-Like Peptide-1 Receptor/metabolism , Glucose/metabolism , Hypothalamus/drug effects , Hypothalamus/metabolism , Injections, Intraventricular , Injections, Subcutaneous , Insulin-Secreting Cells/drug effects , Insulin-Secreting Cells/metabolism , Liraglutide/administration & dosage , Male , Medulla Oblongata/drug effects , Mice, Inbred C57BL , Proto-Oncogene Proteins c-fos/metabolism , Vagus Nerve/drug effects
16.
Nat Commun ; 9(1): 113, 2018 01 09.
Article in English | MEDLINE | ID: mdl-29317623

ABSTRACT

Overeating and arrhythmic feeding promote obesity and diabetes. Glucagon-like peptide-1 receptor (GLP-1R) agonists are effective anti-obesity drugs but their use is limited by side effects. Here we show that oral administration of the non-calorie sweetener, rare sugar D-allulose (D-psicose), induces GLP-1 release, activates vagal afferent signaling, reduces food intake and promotes glucose tolerance in healthy and obese-diabetic animal models. Subchronic D-allulose administered at the light period (LP) onset ameliorates LP-specific hyperphagia, visceral obesity, and glucose intolerance. These effects are blunted by vagotomy or pharmacological GLP-1R blockade, and by genetic inactivation of GLP-1R signaling in whole body or selectively in vagal afferents. Our results identify D-allulose as prominent GLP-1 releaser that acts via vagal afferents to restrict feeding and hyperglycemia. Furthermore, when administered in a time-specific manner, chronic D-allulose corrects arrhythmic overeating, obesity and diabetes, suggesting that chronotherapeutic modulation of vagal afferent GLP-1R signaling may aid in treating metabolic disorders.


Subject(s)
Anti-Obesity Agents/pharmacology , Eating/drug effects , Fructose/pharmacology , Glucagon-Like Peptide-1 Receptor/agonists , Hyperphagia/drug therapy , Obesity/drug therapy , Animals , Blood Glucose/drug effects , Glucagon-Like Peptide-1 Receptor/genetics , Glucagon-Like Peptide-1 Receptor/metabolism , Glucose Intolerance/drug therapy , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Rats , Rats, Wistar , Vagus Nerve/drug effects , Vagus Nerve/metabolism
17.
Cell Rep ; 22(3): 706-721, 2018 01 16.
Article in English | MEDLINE | ID: mdl-29346768

ABSTRACT

Food selection is essential for metabolic homeostasis and is influenced by nutritional state, food palatability, and social factors such as stress. However, the mechanism responsible for selection between a high-carbohydrate diet (HCD) and a high-fat diet (HFD) remains unknown. Here, we show that activation of a subset of corticotropin-releasing hormone (CRH)-positive neurons in the rostral region of the paraventricular hypothalamus (PVH) induces selection of an HCD over an HFD in mice during refeeding after fasting, resulting in a rapid recovery from the change in ketone metabolism. These neurons manifest activation of AMP-activated protein kinase (AMPK) during food deprivation, and this activation is necessary and sufficient for selection of an HCD over an HFD. Furthermore, this effect is mediated by carnitine palmitoyltransferase 1c (CPT1c). Thus, our results identify the specific neurons and intracellular signaling pathway responsible for regulation of the complex behavior of selection between an HCD and an HFD. VIDEO ABSTRACT.


Subject(s)
AMP-Activated Protein Kinases/metabolism , Corticotropin-Releasing Hormone/metabolism , Neurons/physiology , Animals , Carbohydrates , Diet , Male , Mice
18.
Am J Physiol Endocrinol Metab ; 315(4): E478-E488, 2018 10 01.
Article in English | MEDLINE | ID: mdl-28174180

ABSTRACT

Light synchronizes the body's circadian rhythms by modulating the master clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. In modern lifestyles that run counter to normal circadian rhythms, the extended and/or irregular light exposure impairs circadian rhythms and, consequently, promotes feeding and metabolic disorders. However, the neuronal pathway through which light is coupled to feeding behavior is less elucidated. The present study employed the light exposure during the dark phase of the day in rats and observed its effect on neuronal activity and feeding behavior. Light exposure acutely suppressed food intake and elevated c-Fos expression in the AVP neurons of SCN and the oxytocin (Oxt) neurons of paraventricular nucleus (PVN) in the hypothalamus. The light-induced suppression of food intake was abolished by blockade of the Oxt receptor in the brain. Retrograde tracer analysis demonstrated the projection of SCN AVP neurons to the PVN. Furthermore, intracerebroventricular injection of AVP suppressed food intake and increased c-Fos in PVN Oxt neurons. Intra-PVN injection of AVP exerted a stronger anorexigenic effect than intracerebroventriclar injection. AVP also induced intracellular Ca2+ signaling and increased firing frequency in Oxt neurons in PVN slices. These results reveal the novel neurocircuit from SCN AVP to PVN Oxt that relays light reception to inhibition of feeding behavior. This light-induced neurocircuit may serve as a pathway for forming the circadian feeding rhythm and linking irregular light exposure to arrhythmic feeding and, consequently, obesity and metabolic diseases.


Subject(s)
Arginine Vasopressin/metabolism , Feeding Behavior/physiology , Light , Oxytocin/metabolism , Paraventricular Hypothalamic Nucleus/metabolism , Suprachiasmatic Nucleus/metabolism , Animals , Arginine Vasopressin/pharmacology , Arginine Vasopressin/physiology , Calcium Signaling/drug effects , Calcium Signaling/physiology , Circadian Rhythm/physiology , Feeding Behavior/drug effects , Hypothalamus/metabolism , Hypothalamus/physiology , Inhibition, Psychological , Male , Neural Pathways , Neurons/drug effects , Neurons/metabolism , Oxytocin/physiology , Paraventricular Hypothalamic Nucleus/physiology , Proto-Oncogene Proteins c-fos/drug effects , Proto-Oncogene Proteins c-fos/metabolism , Rats , Rats, Wistar , Receptors, Oxytocin , Suprachiasmatic Nucleus/physiology
19.
Postgrad Med ; 130(1): 122-128, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29105546

ABSTRACT

OBJECTIVES: Both human and animal studies have suggested that oxytocin may have therapeutic potential in the treatment of schizophrenia. We evaluated the effects of intranasal oxytocin on cognition and its predictive factors in Japanese patients with schizophrenia. METHODS: Subjects were 16 chronic schizophrenia patients who underwent intranasal oxytocin treatment for 3 months and were assessed for changes in severity of clinical symptoms and cognitions. Fifteen of the 16 subjects underwent 3-Tesla magnetic resonance imaging. RESULTS: Oxytocin significantly reduced scores on the positive and negative syndrome scale, especially on the negative symptoms. As for cognition, there was an improvement of the verbal fluency. Furthermore, the change of the negative score in positive and negative syndrome scale showed a negative correlation with the gray matter volumes of the right insula and left cingulate cortex. CONCLUSIONS: Our results indicate that daily administration of intranasal oxytocin may be effective for ameliorating clinical symptoms and cognitive functions in chronic schizophrenia patients, and this improvement may be related to the gray matter volume of the right insula and left cingulate cortex.


Subject(s)
Brain/drug effects , Cognition/drug effects , Oxytocin/therapeutic use , Schizophrenia/drug therapy , Schizophrenic Psychology , Administration, Intranasal , Adult , Appetite/drug effects , Brain/diagnostic imaging , Chemotherapy, Adjuvant , Chronic Disease , Female , Humans , Male , Middle Aged , Psychiatric Status Rating Scales , Schizophrenia/diagnostic imaging
20.
Nat Commun ; 8(1): 490, 2017 09 08.
Article in English | MEDLINE | ID: mdl-28887564

ABSTRACT

Failure to secrete sufficient quantities of insulin is a pathological feature of type-1 and type-2 diabetes, and also reduces the success of islet cell transplantation. Here we demonstrate that Y1 receptor signaling inhibits insulin release in ß-cells, and show that this can be pharmacologically exploited to boost insulin secretion. Transplanting islets with Y1 receptor deficiency accelerates the normalization of hyperglycemia in chemically induced diabetic recipient mice, which can also be achieved by short-term pharmacological blockade of Y1 receptors in transplanted mouse and human islets. Furthermore, treatment of non-obese diabetic mice with a Y1 receptor antagonist delays the onset of diabetes. Mechanistically, Y1 receptor signaling inhibits the production of cAMP in islets, which via CREB mediated pathways results in the down-regulation of several key enzymes in glycolysis and ATP production. Thus, manipulating Y1 receptor signaling in ß-cells offers a unique therapeutic opportunity for correcting insulin deficiency as it occurs in the pathological state of type-1 diabetes as well as during islet transplantation.Islet transplantation is considered one of the potential treatments for T1DM but limited islet survival and their impaired function pose limitations to this approach. Here Loh et al. show that the Y1 receptor is expressed in ß- cells and inhibition of its signalling, both genetic and pharmacological, improves mouse and human islet function.


Subject(s)
Insulin-Secreting Cells/metabolism , Islets of Langerhans Transplantation , Islets of Langerhans/metabolism , Animals , Arginine/analogs & derivatives , Arginine/pharmacology , Cyclic AMP/metabolism , Diabetes Mellitus, Experimental/metabolism , Humans , Insulin/metabolism , Insulin Secretion , Mice , Receptors, Neuropeptide Y/antagonists & inhibitors , Receptors, Neuropeptide Y/metabolism , Signal Transduction
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