| 1999 |
Melanin-concentrating hormone (MCH) was identified as the natural ligand for the orphan G protein-coupled receptor SLC-1 (MCHR1). Using Xenopus oocytes injected with SLC-1 cRNA and GIRK channels, rat brain extracts were purified by cation exchange chromatography and HPLC; mass spectrometry and peptide sequencing confirmed MCH as the active peptide. The receptor couples to both Gi (GIRK-mediated currents) and Gq (phospholipase C / Ca2+-dependent Cl- currents) signaling pathways. |
Xenopus oocyte functional expression, HPLC purification, mass spectrometry, peptide sequencing, electrophysiology |
FEBS letters |
High |
10471841
|
| 2001 |
A second human MCH receptor (MCH-2R / MCH-R2) was identified and characterized. It shares ~38% amino acid identity with MCH-1R, binds MCH with high affinity, and signals exclusively through Gαq (inositol phosphate turnover and intracellular Ca2+ release) without sensitivity to pertussis toxin and without reducing cAMP, indicating it cannot couple to Gi. |
Receptor cloning, radioligand binding, intracellular Ca2+ assay, inositol phosphate assay, cAMP assay, pertussis toxin treatment, Northern blot, in situ hybridization |
Proceedings of the National Academy of Sciences of the United States of America |
High |
11274220 11404457 11459838
|
| 2001 |
Structure-activity relationship studies of MCH at human MCHR1 (SLC-1) established that the minimal agonist sequence is MCH-(6-17) (the disulfide-bridged ring with flanking Arg6 and Trp17). Alanine scanning identified Met8, Arg11, and Tyr13 as essential residues for full potency. Deletion of ring residues produced inactivity or weak antagonists; replacement of the disulfide bridge by an amide bond was detrimental to agonist activity but produced weak antagonists. |
Synthetic peptide analogs, cAMP inhibition assay, [35S]-GTPγS binding, structure-activity relationship mutagenesis |
The Journal of biological chemistry |
High |
11278733
|
| 1998 |
Leptin signaling in the hypothalamus downregulates MCH gene expression, and central leptin administration completely prevents MCH-induced food intake in satiated rats, demonstrating that MCH acts downstream of leptin and that leptin blocks both the synthesis and post-synaptic action of MCH. |
Intracerebroventricular administration, in situ hybridization (gene expression), behavioral food intake measurements |
Endocrinology |
Medium |
9449656 9794487
|
| 2001 |
MCH suppresses TSH release in vivo and in vitro via dual mechanisms: it reduces TRH release from hypothalamic explants and directly inhibits TRH-stimulated TSH release from dispersed pituitary cell cultures, placing MCH as an inhibitory regulator of the hypothalamic-pituitary-thyroid axis. |
ICV administration in rats (in vivo TSH measurement), hypothalamic explant TRH release assay, dispersed pituitary cell culture TSH release assay |
Endocrinology |
Medium |
11416052
|
| 2003 |
Chronic ICV infusion of MCH in mice increases lipogenic activity in WAT and liver and reduces thermogenesis markers (UCP-1, acyl-CoA oxidase, CPT-I mRNA) in brown adipose tissue independently of hyperphagia, establishing a direct role for MCH in promoting fat storage and reducing energy expenditure. |
Chronic ICV infusion, pair-feeding paradigm, lipogenic enzyme activity assays, mRNA expression analysis, rectal temperature measurement |
American journal of physiology. Endocrinology and metabolism |
Medium |
12554598
|
| 2004 |
Using viral AAV-mediated GFP targeting of MCH neurons for identification in hypothalamic slices, monoaminergic arousal transmitters (norepinephrine, serotonin) and muscarinic acetylcholine agonist directly inhibit MCH neurons, NPY inhibits them by pre- and postsynaptic mechanisms, and hypocretin/orexin directly excites MCH neurons (inward current, increased spike frequency). Alpha-melanocortin agonist had no effect. |
AAV-GFP viral targeting, whole-cell patch clamp electrophysiology in hypothalamic slices, pharmacological agonist/antagonist application |
Neuron |
High |
15157424
|
| 2010 |
Glucose excitation of MCH neurons in the lateral hypothalamus is mediated by KATP channel closure (ATP-dependent), and this response is negatively regulated by UCP2 (a mitochondrial protein reducing ATP production). Cell-type-specific manipulation of glucose sensing in MCH neurons regulates peripheral glucose homeostasis. |
Conditional knockout (KATP channel and UCP2 deletion in MCH neurons), electrophysiology, glucose tolerance tests, insulin tolerance tests |
Cell metabolism |
High |
21035764
|
| 2013 |
Optogenetic activation of MCH neurons (10 Hz, channelrhodopsin-2) at the start of the night hastened sleep onset, reduced wake bout length by 50%, and increased total non-REM and REM sleep time, demonstrating that MCH neuronal activity is sufficient to promote sleep and counteract arousal neuron activity. |
Optogenetics (channelrhodopsin-2 AAV in MCH neurons), EEG/EMG polysomnography in freely moving mice |
The Journal of neuroscience : the official journal of the Society for Neuroscience |
High |
23785141
|
| 2014 |
Acute optogenetic activation of MCH neurons during NREM sleep (but not wakefulness) induces transitions to REM sleep and increases REM sleep time while decreasing NREM sleep. Acute optogenetic silencing (archaerhodopsin-T) had no effect on vigilance states. Temporally controlled diphtheria toxin-mediated ablation of MCH neurons increased wakefulness and decreased NREM sleep without affecting REM sleep. |
Optogenetics (ChR2 E123T/T159C and archaerhodopsin-T knockin), cell-specific diphtheria toxin ablation, EEG/EMG polysomnography |
The Journal of neuroscience : the official journal of the Society for Neuroscience |
High |
24828644
|
| 2013 |
Ablation of MCH neurons (using diphtheria toxin targeted to the Pmch locus) in adult mice causes leanness, hyperactivity, and abnormal psychostimulant responses—phenotypes recapitulating MCH knockout—but also improved glucose tolerance that was not seen in MCH-deficient mice, establishing that MCH neurons regulate glucose tolerance through signaling molecules other than MCH itself. |
Diphtheria toxin receptor knockin at Pmch locus, ICV diphtheria toxin injection, metabolic phenotyping, glucose tolerance testing, locomotor activity monitoring |
The Journal of neuroscience : the official journal of the Society for Neuroscience |
Medium |
23365238
|
| 2015 |
Optogenetic stimulation of orexin neurons inhibits action potential firing in most MCH neurons via GABAA receptors (not dynorphin receptors). Orexin cell firing increases the frequency of fast GABAergic currents in MCH cells via an effect blocked by orexin receptor antagonists but not dynorphin or glutamate receptor antagonists, and mimicked by bath-applied orexin peptide. A minority of MCH cells are excited by orexin peptides. This defines an intra-LH feedforward inhibitory microcircuit from orexin to MCH neurons. |
Optogenetics, whole-cell patch clamp, calcium imaging with genetically targeted indicator in MCH neurons, pharmacological receptor antagonism in mouse brain slices |
The Journal of neuroscience : the official journal of the Society for Neuroscience |
High |
25855162
|
| 2016 |
Fiberoptic calcium recordings from MCH neurons in awake freely moving mice show that MCH neurons generate conditional population bursts correlated with novelty exploration, inhibited by stress, and inversely predicted by orexin neuron activity. Brain-wide monosynaptic input mapping identified VGAT neurons in the amygdala and bed nucleus of stria terminalis as direct inhibitory controllers of MCH neurons, confirmed by optogenetic stimulation. |
Fiber photometry (GCaMP in MCH neurons), monosynaptic rabies virus tracing, optogenetics, freely moving awake recordings |
Nature communications |
High |
27102565
|
| 2016 |
Insulin activates MCH neurons via PI3K signaling; cell-type-specific deletion of the insulin receptor (IR) in MCH neurons in obese mice improves locomotor activity and insulin sensitivity. Acute chemogenetic (DREADD) activation of MCH neurons impairs locomotor activity but not insulin sensitivity, dissociating the two phenotypic effects. |
Conditional IR knockout in MCH neurons (IRΔMCH), immunostaining for phospho-Akt, DREADD chemogenetics, metabolic and locomotor phenotyping under normal and high-fat diet |
Cell reports |
Medium |
27926856
|
| 2016 |
Central CCL2 signaling acts on MCH neurons to mediate sickness behavior: MCH neurons express the CCL2 receptor (CCR2), and central CCL2 delivery decreases MCH neuronal electrical activity and MCH peptide release. Pharmacological or genetic inhibition of CCL2 signaling opposes LPS-induced decreases in MCH and body weight. |
Electrophysiology in MCH neurons, ex vivo MCH release measurement, CCL2 ICV delivery, CCR2 antagonism/genetic deletion, LPS model |
EMBO reports |
Medium |
27733491
|
| 2019 |
MCH reduces POMC neuronal activity and acts through a SIRT1/FoxO1 signaling pathway in arcuate nucleus POMC neurons to induce hyperphagia, adiposity, and glucose intolerance. The orexigenic effects of MCH are independent of AgRP neurons (GABA-A receptor blockade in ARC did not prevent MCH-induced feeding; MCH silencing-induced hypophagia persisted after chemogenetic AgRP stimulation). Central SIRT1 mediates MCH-induced weight gain via effects on the sympathetic nervous system. |
Conditional SIRT1 knockout in POMC neurons, SIRT1 overexpression, ICV MCH administration, chemogenetic AgRP stimulation, electrophysiology of POMC neurons, GABA-A antagonism |
Diabetes |
Medium |
31530579
|
| 2020 |
MCH neurons project densely to the median eminence (ME) in proximity to tanycytes and fenestrated vessels. Chemogenetic or optogenetic activation of MCH neuron projections in the ME increases ME permeability (fenestrated vascular loops) and enhances leptin action in the arcuate nucleus. MCH neurons express VEGFA, and blocking VEGF-R signaling attenuates the leptin-sensitizing effect of MCH neuron activation. Phospho-RiboTrap analysis identified endothelial cells as MCH-neuron-dependent targets. |
Chemogenetics (DREADD), optogenetics, unbiased phosphoRiboTrap cell-activation assay, vascular permeability assays, VEGF-R blockade, immunofluorescence |
Neuron |
High |
32407670
|
| 2021 |
Activation of the MCH system (via MCHR1 agonist, optogenetic or chemogenetic MCH neuron stimulation) shortens neuronal primary cilia (detected by ADCY3 marker quantification), while inactivation (pharmacological MCHR1 blockade, germline MCHR1 deletion, or conditional MCH neuron ablation) lengthens cilia, establishing a causal role of MCH signaling in regulating brain neuronal primary cilia length. |
Pharmacological MCHR1 agonist/antagonist, germline MCHR1 KO, conditional MCH neuron ablation, optogenetics, DREADD chemogenetics, quantitative ADCY3 immunofluorescence in organotypic brain slices and in vivo |
Molecular neurobiology |
Medium |
34665407
|
| 2012 |
Vasopressin and oxytocin directly excite MCH neurons (depolarization, increased spike frequency) in a TTX-resistant manner via V1aR and oxytocin receptors (confirmed by single-cell RT-PCR for V1aR and OTR mRNA in MCH cells). The vasopressin depolarization involves Na+/Ca2+ exchanger activation and opening of nonselective cation channels. These excitatory effects were absent in neighboring non-MCH GABA neurons (GAD67-GFP), indicating specificity. |
Whole-cell patch clamp in MCH-GFP and GAD67-GFP hypothalamic slices, Na+/Ca2+ exchanger blockers, BAPTA, ion substitution, single-cell RT-PCR |
American journal of physiology. Regulatory, integrative and comparative physiology |
High |
22262306
|
| 2000 |
MCH receptor (SLC-1/MCHR1) mRNA and protein are expressed in insulin-producing cell lines (CRI-G1, RINm5F) and rat islets of Langerhans, with cell-surface receptor immunofluorescence. Rat MCH significantly stimulates insulin secretion from both cell lines, and this effect is potentiated by forskolin, suggesting MCH amplifies cAMP-dependent insulinotropic stimuli. |
RT-PCR, immunofluorescence, insulin secretion assay with forskolin co-treatment |
Biochemical and biophysical research communications |
Medium |
10964727
|
| 2008 |
MCH knockout mice show elevated dopamine transporter (DAT) expression and enhanced DAT-mediated dopamine uptake in the nucleus accumbens, increased evoked dopamine release in the Acb shell, enhanced behavioral sensitization to amphetamine, and greater locomotor response to a DAT inhibitor, establishing that endogenous MCH signaling regulates mesolimbic dopamine system function. |
Immunoblotting for DAT, D1R, D2R; amperometry in ex vivo Acb slices; locomotor activity measurements after amphetamine and GBR 12909; catalepsy bar test; in situ hybridization |
Biological psychiatry |
Medium |
18281019
|
| 2009 |
Pmch−/− rats are lean, hypophagic, and show reduced bone density. Body weight set point is determined predominantly during the first 8 postnatal weeks, and loss of Pmch during this developmental window establishes a 20% lower body weight set point that persists into adulthood, demonstrating that early developmental Pmch expression is critical for normal energy homeostasis programming. |
Rat Pmch knockout model, longitudinal body weight tracking, feeding behavior analysis, endocrine parameter measurements, calorimetry |
American journal of physiology. Endocrinology and metabolism |
Medium |
19934402
|
| 2008 |
MCH modulates intestinal inflammatory responses: MCH and MCHR1 are upregulated in intestinal xenografts by C. difficile toxin A; MCH treatment of colonocytes upregulates IL-8 transcription; MCH-deficient mice show attenuated toxin A-induced intestinal inflammation and secretion; immunoneutralization of MCH or MCHR1 in wild-type mice similarly attenuates the response. |
Human intestinal xenograft model, RT-PCR, IL-8 transcriptional assay in colonocytes, MCH KO mice, immunoneutralization with anti-MCH and anti-MCHR1 antibodies, intestinal fluid secretion measurement |
Gut |
Medium |
18824554
|
| 1987 |
In rat dorsolateral hypothalamus, MCH and alpha-MSH are co-localized in the same neuronal cell bodies and in the same dense core vesicles, as demonstrated by immunoelectron microscopy double-staining. In the human hypothalamus, MCH and alpha-MSH neurons do not co-localize. |
Immunofluorescence, peroxidase-anti-peroxidase immunocytochemistry, immunoelectron microscopy, double-staining |
Brain research |
Medium |
2823986
|
| 1997 |
NK3 receptor (neurokinin B receptor) is immunocytochemically co-expressed on 57% of MCH neurons in the rat lateral hypothalamus and zona incerta, but not on neighboring prolactin-immunoreactive neurons, providing evidence that neurokinin B can regulate MCH neuronal activity via NK3 receptor. |
Immunocytochemistry, in situ hybridization for NK3 receptor, double-labeling with MCH and prolactin-ir neurons |
Journal of chemical neuroanatomy |
Low |
9141650
|
| 2006 |
MCH stimulates GH secretion from human fetal pituitary cultures and GH-secreting pituitary adenoma cells via MCH-R1 (but not MCH-R2, which is not expressed in these tissues). MCH treatment of GH adenoma cells induces ERK1/2 phosphorylation, indicating MCH-R1-mediated activation of MAP kinase signaling. Neuropeptide EI (co-encoded by the PMCH gene) also stimulates GH secretion from fetal pituitaries. |
GH secretion assay in human fetal pituitary cultures and GH adenoma cell cultures, RT-PCR for receptor expression, ERK1/2 phosphorylation immunoblot |
American journal of physiology. Endocrinology and metabolism |
Medium |
16603725
|
| 1991 |
In teleost melanocytes, MCH-induced melanosome aggregation is mediated via protein kinase C: phospholipase C inhibitors (4-bromophenacyl bromide, neomycin) shift the MCH dose-response curve; low-dose phorbol ester (TPA) mimics MCH pigment aggregation; PKC inhibitors (dibucaine, H-7) attenuate MCH effects. A protein dephosphorylation step is common to both MCH and norepinephrine lightening actions. |
In vitro eel skin melanocyte assay, pharmacological inhibitors of PLC and PKC, phorbol ester agonism, phosphatase inhibitor |
Pigment cell research |
Medium |
1946211
|
| 2018 |
Sleep deprivation increases GLT1 apposition around MCH neuron somata, which functionally decreases the postsynaptic response of MCH neurons to high-frequency synaptic activation without changing presynaptic glutamate release. In contrast, GLT1 apposition around orexin neurons decreases after sleep deprivation. These changes reverse after sleep recovery, demonstrating astrocyte-mediated, state-dependent, cell-type-specific modulation of MCH neuron excitability. |
Quantitative immunohistochemistry for GLT1, whole-cell patch clamp in lateral hypothalamic slices, GLT1 inhibitor pharmacology, sleep deprivation and recovery paradigms in rats |
The Journal of neuroscience : the official journal of the Society for Neuroscience |
Medium |
29431649
|
| 2020 |
Selective deletion of oxytocin receptors from MCH neurons alters depressive behavior in a sex- and experience-dependent manner: increases depressive behavior in sexually naïve female mice, decreases it in late postpartum females, with no effect in sexually naïve males. The oxytocin-MCH pathway mediates the effects of sexual activity on depressive behavior, associated with changes in Arc (synaptic plasticity marker) expression in reward and fear circuits. |
Conditional oxytocin receptor knockout in MCH neurons (Cre-lox), forced swim test, Arc immunostaining, cohorts with defined mating/parenting history |
Scientific reports |
Low |
32788646
|
| 2005 |
Both Pmch−/− and Mch1r−/− mice show enhanced voluntary running wheel activity compared to wild-type controls, establishing that endogenous MCH signaling plays an inhibitory role in regulating locomotor activity. Naloxone suppressed wheel running in both genotypes, indicating opioid regulation of locomotor activity operates independently of MCH. |
Running wheel monitoring in knockout mice, naloxone pharmacology, dynorphin mRNA measurement |
Regulatory peptides |
Medium |
15544841
|
| 2010 |
Microinjection of MCH into the dorsal raphe nucleus (DRN) elicits dose- and time-dependent depressive-like behavior (increased immobility in forced swim test) mediated by MCH-1 receptors (blocked by intra-DRN MCH-1R antagonist ATC0175). This effect is prevented by fluoxetine pretreatment and reversed by immunoneutralization of MCH within the DRN. |
Intra-DRN MCH microinjection, forced swim test, open field test, MCH-1R antagonist ATC0175, fluoxetine pretreatment, anti-MCH immunoneutralization |
Behavioural brain research |
Medium |
21056060 25006977
|
| 1994 |
The authentic human PMCH gene (encoding MCH, NEI, and NGE) is located on chromosome 12q23-q24 by Southern blot with somatic cell hybrids and FISH. Two variant MCH-like genes (PMCHL1 and PMCHL2) map to chromosomes 5p14 and 5q12-q13, respectively. |
Southern blotting with somatic cell hybrid panel, fluorescence in situ hybridization (FISH) |
Genomics |
Medium |
8188237
|
| 2000 |
The MCH gene in rats produces alternatively spliced transcripts: the precursor encoding MCH and neuropeptide EI (expressed in zona incerta/lateral hypothalamus), and a putative protein MGOP. MGOP co-localizes with MCH in 98% of LHA/ZI perikarya but has distinct projections to suprachiasmatic, ventromedial, arcuate nuclei, and median eminence external layer where MCH fibers are absent, and is expressed in additional non-MCH neurons. |
Northern blot, RT-PCR, in situ hybridization, Western blot (12 kDa protein), RP-HPLC + RIA, immunohistochemistry with MGOP-specific antiserum, COS7 cell transfection |
The European journal of neuroscience |
Medium |
11122347
|