Sneezing reflex is mediated by a peptidergic pathway from nose to brainstem.

Sneezing is a vital respiratory reflex frequently associated with allergic rhinitis and viral respiratory infections. However, its neural circuit remains largely unknown. A sneeze-evoking region was discovered in both cat and human brainstems, corresponding anatomically to the central recipient zone of nasal sensory neurons. Therefore, we hypothesized that a neuronal population postsynaptic to nasal sensory neurons mediates sneezing in this region. By screening major presynaptic neurotransmitters/neuropeptides released by nasal sensory neurons, we found that neuromedin B (NMB) peptide is essential for signaling sneezing. Ablation of NMB-sensitive postsynaptic neurons in the sneeze-evoking region or deficiency in NMB receptor abolished the sneezing reflex. Remarkably, NMB-sensitive neurons further project to the caudal ventral respiratory group (cVRG). Chemical activation of NMB-sensitive neurons elicits action potentials in cVRG neurons and leads to sneezing behavior. Our study delineates a peptidergic pathway mediating sneezing, providing molecular insights into the sneezing reflex arc.

Basophils prime group 2 innate lymphoid cells for neuropeptide-mediated inhibition.

Type 2 cytokine responses promote parasitic immunity and initiate tissue repair; however, they can also result in immunopathologies when not properly restricted. Although basophilia is recognized as a common feature of type 2 inflammation, the roles basophils play in regulating these responses are unknown. Here, we demonstrate that helminth-induced group 2 innate lymphoid cell (ILC2) responses are exaggerated in the absence of basophils, resulting in increased inflammation and diminished lung function. Additionally, we show that ILC2s from basophil-depleted mice express reduced amounts of the receptor for the neuropeptide neuromedin B (NMB). Critically, NMB stimulation inhibited ILC2 responses from control but not basophil-depleted mice, and basophils were sufficient to directly enhance NMB receptor expression on ILC2s. These studies suggest that basophils prime ILC2s to respond to neuron-derived signals necessary to maintain tissue integrity. Further, these data provide mechanistic insight into the functions of basophils and identify NMB as a potent inhibitor of type 2 inflammation.

Constitutively active BRS3 is a genuinely orphan GPCR in placental mammals.

G protein-coupled receptors (GPCRs) play an important role in physiology and disease and represent the most productive drug targets. Orphan GPCRs, with their endogenous ligands unknown, were considered a source of drug targets and consequently attract great interest to identify their endogenous cognate ligands for deorphanization. However, a contrary view to the ubiquitous existence of endogenous ligands for every GPCR is that there might be a significant overlooked fraction of orphan GPCRs that function constitutively in a ligand-independent manner only. Here, we investigated the evolution of the bombesin receptor-ligand family in vertebrates in which one member-bombesin receptor subtype-3 (BRS3)-is a potential orphan GPCR. With analysis of 17 vertebrate BRS3 structures and 10 vertebrate BRS3 functional data, our results demonstrated that nonplacental vertebrate BRS3 still connects to the original ligands-neuromedin B (NMB) and gastrin-releasing peptide (GRP)-because of adaptive evolution, with significantly changed protein structure, especially in three altered key residues (Q127R, P205S, and R294H) originally involved in ligand binding/activation, whereas the placental mammalian BRS3 lost the binding affinity to NMB/GRP and constitutively activates Gs/Gq/G12 signaling in a ligand-independent manner. Moreover, the N terminus of placental mammalian BRS3 underwent positive selection, exhibiting significant structural differences compared to nonplacental vertebrate BRS3, and this domain plays an important role in constitutive activity of placental mammalian BRS3. In conclusion, constitutively active BRS3 is a genuinely orphan GPCR in placental mammals, including human. To our knowledge, this study identified the first example that might represent a new group of genuinely orphan GPCRs that will never be deorphanized by the discovery of a natural ligand and provided new perspectives in addition to the current ligand-driven GPCR deorphanization.

The peptidergic control circuit for sighing.

Sighs are long, deep breaths expressing sadness, relief or exhaustion. Sighs also occur spontaneously every few minutes to reinflate alveoli, and sighing increases under hypoxia, stress, and certain psychiatric conditions. Here we use molecular, genetic, and pharmacologic approaches to identify a peptidergic sigh control circuit in murine brain. Small neural subpopulations in a key breathing control centre, the retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG), express bombesin-like neuropeptide genes neuromedin B (Nmb) or gastrin-releasing peptide (Grp). These project to the preBötzinger Complex (preBötC), the respiratory rhythm generator, which expresses NMB and GRP receptors in overlapping subsets of ~200 neurons. Introducing either neuropeptide into preBötC or onto preBötC slices, induced sighing or in vitro sigh activity, whereas elimination or inhibition of either receptor reduced basal sighing, and inhibition of both abolished it. Ablating receptor-expressing neurons eliminated basal and hypoxia-induced sighing, but left breathing otherwise intact initially. We propose that these overlapping peptidergic pathways comprise the core of a sigh control circuit that integrates physiological and perhaps emotional input to transform normal breaths into sighs.

Neuromedin B regulates steroidogenesis, cell viability and apoptosis in rabbit Leydig cells.

Mammalian bombesin-related peptide, neuromedin B (NMB) action is mediated by its receptor (NMBR), and NMB/NMBR system plays a major role in regulating hormone secretions, reproduction and cell growth. Here we report the functions of NMB in regulating steroidogenesis (testosterone synthesis), cell viability and apoptosis. The primary rabbit Leydig cells were employed as the paradigm for this research. We initially confirmed that NMBR is distributed in Leydig cells of rabbit testis, and a certain dose of NMB could increase the secretion of testosterone in primary cultured rabbit Leydig cells. Subsequently, the accumulated NMBR, StAR, CYP11A1, 3ß-HSD and PKC protein could be induced by a certain dose of NMB in Leydig cells. Moreover, we found that NMB could decrease the cell viability, and decreased the expression of PCNA protein in Leydig cells; meanwhile, except for 100 nM, other doses of NMB could suppress the cell apoptosis, and regulate Caspase-3 protein expression in Leydig cells, respectively. These results identify that NMB may be a key factor in regulating testosterone synthesis through taking part in NMBR/PKC/steroidogenesis signaling pathway, as well as the cell viability and proliferation in rabbit Leydig cells.

Preclinical Evaluation of NHS-Activated Gold Nanoparticles Functionalized with Bombesin or Neurotensin-Like Peptides for Targeting Colon and Prostate Tumours.

Recent advances and large-scale use of hybrid imaging modalities like PET-CT have led to the necessity of improving nano-drug carriers that can facilitate both functional and metabolic screening in nuclear medicine applications. In this study, we focused on the evaluation of four potential imaging nanoparticle structures labelled with the 68Ga positron emitter. For this purpose, we functionalized NHS-activated PEG-gold nanoparticles with 68Ga-DOTA-Neuromedin B, 68Ga-DOTA-PEG(4)-BBN(7-14), 68Ga-DOTA-NT and 68Ga-DOTA-Neuromedin N. In vitro binding kinetics and specific binding to human HT-29 colon carcinoma cells and DU-145 prostate carcinoma cells respectively were assessed, over 75% retention being obtained in the case of 68Ga-DOTA-PEG(4)-BBN(7-14)-AuNP in prostate tumour cells and over 50% in colon carcinoma cells. Biodistribution in NU/J mice highlighted a three-fold uptake increase in tumours at 30 min post-injection of 68Ga-DOTA-NT-AuNP and 68Ga-DOTA-PEG(4)-BBN(7-14)-AuNP compared to 68Ga-DOTA-NT and 68Ga-DOTA-PEG(4)-BBN(7-14) respectively, therewith fast distribution in prostate and colon tumours and minimum accumulation in non-targeted tissues.

A 4-gene panel predicting the survival of patients with glioblastoma.

BACKGROUND: To identify independently prognostic gene panel in patients with glioblastoma (GBM). MATERIALS AND METHODS: The Cancer Genome Atlas (TCGA)-GBM was used as a training set and a test set. GSE13041 was used as a validation set. Survival associated differentially expression genes (DEGs), derived between GBM and normal brain tissue, was obtained using univariate Cox proportional hazards regression model and then was included in a least absolute shrinkage and selection operator penalized Cox proportional hazards regression model. Thus, a 4-gene prognostic panel was developed based on the risk score for each patient in that model. The prognostic role of the 4-gene panel was validated using univariate and multivariable Cox proportional hazards regression model. RESULTS: A total of 686 patients with GBM were included in our study; 724 DEGs was identified, 133 of which was significantly correlated with the overall survival (OS) of patients with GBM. A 4-gene panel including NMB, RTN1, GPC5, and epithelial membrane protein 3 (EMP3) was developed. Kaplan-Meier survival analysis suggested that patients in the 4-gene panel low risk group had significantly better OS than those in the 4-gene panel high risk group in the training set (hazard ratio [HR] = 0.3826; 95% confidence interval [CI]: 0.2751-0.532; P < 0.0001), test set (HR = 0.718; 95% CI: 0.5282-0.9759; P = 0.033) and the independent validation set (HR = 0.6898; 95% CI: 0.4872-0.9766; P = 0.035). Both univariate and multivariable Cox proportional hazards regression analysis suggested that the 4-gene panel was independent prognostic factor for GBM in the training set. CONCLUSION: We developed and validated 4-gene panel that was independently correlated with the survival of patients with GBM.

Role of neuromedin B and its receptor in the innate immune responses against influenza A virus infection in vitro and in vivo.

The peptide neuromedin B (NMB) and its receptor (NMBR) represent a system (NMB/NMBR) of neuromodulation. Here, it was demonstrated that the expression of NMBR in cells or murine lung tissues was clearly upregulated in response to H1N1/PR8 influenza A virus infection. Furthermore, the in vitro and in vivo activities of NMB/NMBR during PR8 infection were investigated. It was observed that A549 cells lacking endogenous NMBR were more susceptible to virus infection than control cells, as evidenced by the increased virus production in the cells. Interestingly, a significant decrease in IFN-α and increased IL-6 expression were observed in these cells. The role of this system in innate immunity against PR8 infection was probed by treating mice with NMB. The NMB-treated mice were less susceptible to virus challenge, as evidenced by increased survival, increased body weight, and decreased viral NP expression compared with the control animals. Additionally, the results showed that exogenous NMB not only enhanced IFN-α expression but also appeared to inhibit the expression of NP and IL-6 in PR8-infected cells and animals. As expected, opposing effects were observed in the NMBR antagonist-treated cells and mice, which further confirmed the effects of NMB. Together, these data suggest that NMB/NMBR may be an important component of the host defence against influenza A virus infection. Thus, these proteins may serve as promising candidates for the development of novel antiviral drugs.

Neuromedin B Induces Acute Itch in Mice via the Activation of Peripheral Sensory Neurons.

Neuromedin B is expressed in nociceptive and itch-sensitive dorsal root ganglia neurons, but its peripheral pruritogenic potential is not well described. The potential of neuromedin B as a pruritogen and pro-inflammatory peptide in the skin was tested in vivo in an acute model in mice and monkeys as well as an allergic dermatitis model in mice. To identify the underlying mechanisms in vitro real time PCR analysis for neuromedin B and its receptor expression in murine mast cells and dorsal root ganglia as well as functional calcium imaging in the ganglia was applied. Neuromedin B induces itch when injected intradermally, and the peripheral signal is likely transmitted through the activation of dorsal root ganglia. Thus, neuromedin B could be an interesting new therapeutic target for peripheral processing of itch at the level of sensory neurons.

Neuromedin B Expression Defines the Mouse Retrotrapezoid Nucleus.

The retrotrapezoid nucleus (RTN) consists, by definition, of Phox2b-expressing, glutamatergic, non-catecholaminergic, noncholinergic neurons located in the parafacial region of the medulla oblongata. An unknown proportion of RTN neurons are central respiratory chemoreceptors and there is mounting evidence for biochemical diversity among these cells. Here, we used multiplexed in situ hybridization and single-cell RNA-Seq in male and female mice to provide a more comprehensive view of the phenotypic diversity of RTN neurons. We now demonstrate that the RTN of mice can be identified with a single and specific marker, Neuromedin B mRNA (Nmb). Most (∼75%) RTN neurons express low-to-moderate levels of Nmb and display chemoreceptor properties. Namely they are activated by hypercapnia, but not by hypoxia, and express proton sensors, TASK-2 and Gpr4. These Nmb-low RTN neurons also express varying levels of transcripts for Gal, Penk, and Adcyap1, and receptors for substance P, orexin, serotonin, and ATP. A subset of RTN neurons (∼20-25%), typically larger than average, express very high levels of Nmb mRNA. These Nmb-high RTN neurons do not express Fos after hypercapnia and have low-to-undetectable levels of Kcnk5 or Gpr4 transcripts; they also express Adcyap1, but are essentially devoid of Penk and Gal transcripts. In male rats, Nmb is also a marker of the RTN but, unlike in mice, this gene is expressed by other types of nearby neurons located within the ventromedial medulla. In sum, Nmb is a selective marker of the RTN in rodents; Nmb-low neurons, the vast majority, are central respiratory chemoreceptors, whereas Nmb-high neurons likely have other functions.SIGNIFICANCE STATEMENT Central respiratory chemoreceptors regulate arterial PCO2 by adjusting lung ventilation. Such cells have recently been identified within the retrotrapezoid nucleus (RTN), a brainstem nucleus defined by genetic lineage and a cumbersome combination of markers. Using single-cell RNA-Seq and multiplexed in situ hybridization, we show here that a single marker, Neuromedin B mRNA (Nmb), identifies RTN neurons in rodents. We also suggest that >75% of these Nmb neurons are chemoreceptors because they are strongly activated by hypercapnia and express high levels of proton sensors (Kcnk5 and Gpr4). The other RTN neurons express very high levels of Nmb, but low levels of Kcnk5/Gpr4/pre-pro-galanin/pre-pro-enkephalin, and do not respond to hypercapnia. Their function is unknown.

Breathing regulation and blood gas homeostasis after near complete lesions of the retrotrapezoid nucleus in adult rats.

KEY POINTS: The retrotrapezoid nucleus (RTN) drives breathing proportionally to brain PCO2 but its role during various states of vigilance needs clarification. Under normoxia, RTN lesions increased the arterial PCO2 set-point, lowered the PO2 set-point and reduced alveolar ventilation relative to CO2 production. Tidal volume was reduced and breathing frequency increased to a comparable degree during wake, slow-wave sleep and REM sleep. RTN lesions did not produce apnoeas or disordered breathing during sleep. RTN lesions in rats virtually eliminated the central respiratory chemoreflex (CRC) while preserving the cardiorespiratory responses to hypoxia; the relationship between CRC and number of surviving RTN Nmb neurons was an inverse exponential. The CRC does not function without the RTN. In the quasi-complete absence of the RTN and CRC, alveolar ventilation is reduced despite an increased drive to breathe from the carotid bodies. ABSTRACT: The retrotrapezoid nucleus (RTN) is one of several CNS nuclei that contribute, in various capacities (e.g. CO2 detection, neuronal modulation) to the central respiratory chemoreflex (CRC). Here we test how important the RTN is to PCO2 homeostasis and breathing during sleep or wake. RTN Nmb-positive neurons were killed with targeted microinjections of substance P-saporin conjugate in adult rats. Under normoxia, rats with large RTN lesions (92 ± 4% cell loss) had normal blood pressure and arterial pH but were hypoxic (-8 mmHg PaO2 ) and hypercapnic (+10 mmHg ). In resting conditions, minute volume (VE ) was normal but breathing frequency (fR ) was elevated and tidal volume (VT ) reduced. Resting O2 consumption and CO2 production were normal. The hypercapnic ventilatory reflex in 65% FiO2 had an inverse exponential relationship with the number of surviving RTN neurons and was decreased by up to 92%. The hypoxic ventilatory reflex (HVR; FiO2 21-10%) persisted after RTN lesions, hypoxia-induced sighing was normal and hypoxia-induced hypotension was reduced. In rats with RTN lesions, breathing was lowest during slow-wave sleep, especially under hyperoxia, but apnoeas and sleep-disordered breathing were not observed. In conclusion, near complete RTN destruction in rats virtually eliminates the CRC but the HVR persists and sighing and the state dependence of breathing are unchanged. Under normoxia, RTN lesions cause no change in VE but alveolar ventilation is reduced by at least 21%, probably because of increased physiological dead volume. RTN lesions do not cause sleep apnoea during slow-wave sleep, even under hyperoxia.

Neuromedin B and its receptor silencing suppresses osteoclast generation by modulating precursor proliferation via M-CSF/c-Fms/D-type cyclins.

Neuromedin B (NMB), a mammalian bombesin-like peptide, regulates diverse physiological processes, such as energy metabolism, memory and fear behavior, and cellular growth, through its cognate receptor, NMBR. In this study, we report that NMB expression was upregulated during osteoclast development and that silencing NMB or NMBR attenuated osteoclast generation mediated by macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-κB ligand (RANKL). We found that knockdown of NMB or NMBR using a small hairpin RNA suppressed M-CSF-induced proliferation of osteoclast precursor cells without altering osteoclast differentiation. Interestingly, NMB or NMBR knockdown reduced the expression of the M-CSF receptor, c-Fms, which is an important modulator of osteoclast development. Consequently, NMB or NMBR silencing inhibited M-CSF/c-Fms-mediated downstream signaling pathways like activation of ERK and Akt and induction of D-type cyclins, cyclin D1 and D2. Moreover, knockdown of NMB or NMBR accelerated apoptosis in osteoclast lineage cells by inducing caspase-3, caspase-9, and Bim expression. In summary, our study demonstrates that the NMB/NMBR axis plays a pivotal role in osteoclast generation by modulating the proliferation and survival of osteoclast lineage cells.

Effects of MC4R, FTO, and NMB gene variants to obesity, physical activity, and eating behavior phenotypes.

Obesity is a major contributory factor of morbidity and mortality. It has been suggested that biological systems may be involved in the tendency to be and to remain physically inactive also behaviors such as food and beverage preferences and nutrient intake may at least partially genetically determined. Consequently, besides environment, genetic factors may also contribute to the level of physical activity and eating behaviors thus effect obesity. Therefore the aim of this study is to investigate the effect of various gene mutations on obesity, physical activity levels and eating behavior phenotypes. One hundred patients and 100 controls were enrolled to the study. Physical activity levels were measured with an actical acceloremeter device. Eating behaviors were evaluated using Three-Factor Eating questionnaire (TFEQ). Associations between eating behavior scores and physical characteristics were also evaluated. The information about other obesity risk factors were also collected. Mutations were investigated with PCR, direct sequencing and Real-Time PCR. rs1051168, rs8050146 -2778C > T mutations were found statistically significant in patients, rs1121980 was found statistically significant in controls. 21 mutations were found in MC4R and near MC4R of which 18 of them are novel and 8 of them cause amino acid change. In addition, it was found that, some obesity related factors and questions of TFEQ are associated with various investigated gene mutations. Any relation between gene mutations and physical activity levels were not detected. It is thought that, due to the genotype data and eating behaviors, it may be possible to recommend patients for proper eating patterns to prevent obesity. © 2016 IUBMB Life, 68(10):806-816, 2016.

Mice with Deletion of Neuromedin B Receptor Exhibit Decreased Oral Glucose-Stimulated Insulin Release.

Neuromedin B (NB) and gastrin-releasing peptide (GRP) are bombesin-like peptides, found in the gastrointestinal tube and pancreas, among other tissues. Consistent data proposed that GRP stimulates insulin secretion, acting directly in pancreatic cells or in the release of gastrointestinal hormones that are incretins. However, the role of NB remains unclear. We examined the glucose homeostasis in mice with deletion of NB receptor (NBR-KO). Female NBR-KO exhibited similar fasting basal glucose with lower insulinemia (48.4%) and lower homeostasis model assessment of insulin resistance index (50.5%) than wild type (WT). Additionally, they were more tolerant to oral glucose, demonstrated by a decrease in the area under the glucose curve (18%). In addition, 15 min after an oral glucose load, female and male NBR-KO showed lower insulin serum levels (45.6 and 26.8%, respectively) than WT, even though blood glucose rose to similar levels in both groups. Single injection of NB, one hour before the oral glucose administration, tended to induce higher serum insulin in WT (28.9%, p=0.3), however the same did not occur in NBR-KO. They showed no changes in fasting insulin content in pancreatic islets by immunohistochemistry, however, the fasting serum levels of glucagon-like peptide, a potent incretin, exhibited a strong trend to reduction (40%, p=0.07). Collectively, mice with deletion of NB receptor have lower insulinemia, especially in response to oral glucose, and females also exhibited a better glucose tolerance, suggesting the involvement of NB and its receptor in regulation of insulin secretion induced by incretins, and also, in insulin sensitivity.

[The experience with the use of neuromedin preparations for the treatment of sensorineural impairment of hearing].

The objective of the present study was to evaluate the effectiveness of the application of neuromedin for the treatment of sensorineural loss of hearing of different etiology. A total of 230 patients at the age varying from 20 to 60 years presenting with sensorineural impairment of hearing were available for the observation. Neuromedin was administered intramuscularly at 15 mg/day (1.5% solution at a dose of 1.0 ml) for 10 day; thereafter, the patients took 20 mg neuromedin tablets thrice daily during one month. The majority of the patients reported an improvement of hearing and speech intelligibility. Complete restoration of hearing was documented in certain patients presenting with acute sensorineural impairment of hearing.

A nociceptive signaling role for neuromedin B.

Here we used an array-based differential screen to uncover the expression of the neuropeptide neuromedin B (NMB) in the trigeminal ganglia of mice. Double-labeling experiments reveal NMB is expressed in a subset of sensory neurons that colabel with calcitonin gene-related peptide and TRPV1 suggestive of a role for NMB in nociception. Indeed, administration of NMB antagonist greatly attenuates edema and nerve sensitization following stimulation of peripheral nerves with mustard oil, demonstrating that NMB contributes to neurogenic inflammation. Moreover, direct injection of NMB causes local swelling and nociceptive sensitization. Interestingly, we also find that the receptor for NMB is expressed in interneurons in the superficial layers of the dorsal horn. We used NMB-saporin to specifically eliminate NMBR-expressing neurons and determined they are required in responses to noxious heat, but not for reaction to mechanical and pruritic stimuli. Thus, NMB may be a neurotransmitter that is selectively involved in the perception of thermal stimuli.

Genetic variants predicting left ventricular hypertrophy in a diabetic population: a Go-DARTS study including meta-analysis.

BACKGROUND: Left ventricular hypertrophy has multiple aetiologies including diabetes and genetic factors. We aimed to identify genetic variants predicting left ventricular hypertrophy in diabetic individuals. METHODS: Demographic, echocardiographic, prescribing, morbidity, mortality and genotyping databases connected with the Genetics of Diabetes Audit and Research in Tayside, Scotland project were accurately linked using a patient-specific identifier. Left ventricular hypertrophy cases were identified using echocardiographic data.Genotyping data from 973 cases and 1443 non-left ventricular hypertrophy controls were analysed, investigating whether single nucleotide polymorphisms associated with left ventricular hypertrophy in previous Genome Wide Association Studies predicted left ventricular hypertrophy in our population of individuals with type 2 diabetes. Meta-analysis assessed overall significance of these single nucleotide polymorphisms, which were also used to create gene scores. Logistic regression assessed whether these scores predicted left ventricular hypertrophy. RESULTS: Two single nucleotide polymorphisms previously associated with left ventricular hypertrophy were significant: rs17132261: OR 2.03, 95% CI 1.10-3.73, p-value 0.02 and rs2292462: OR 0.82, 95% CI 0.73-0.93 and p-value 2.26x10-3. Meta-analysis confirmed rs17132261 and rs2292462 were associated with left ventricular hypertrophy (p=1.03x10-8 and p=5.86x10-10 respectively) and one single nucleotide polymorphisms in IGF1R (rs4966014) became genome wide significant upon meta-analysis although was not significant in our study. Gene scoring based on published single nucleotide polymorphisms also predicted left ventricular hypertrophy in our study.Rs17132261, within SLC25A46, encodes a mitochondrial phosphate transporter, implying abnormal myocardial energetics contribute to left ventricular hypertrophy development. Rs2292462 lies within the obesity-implicated neuromedin B gene. Rs4966014 lies within the IGF1R1 gene. IGF1 signalling is an established factor in cardiac hypertrophy. CONCLUSIONS: We created a resource to study genetics of left ventricular hypertrophy in diabetes and validated our left ventricular hypertrophy phenotype in replicating single nucleotide polymorphisms identified by previous genome wide association studies investigating left ventricular hypertrophy.

Effect of potential on temperature-dependent SERS spectra of neuromedin B on Cu electrode.

Adsorption of decapeptide neuromedin B (NMB) on copper electrode has been investigated by in situ surface-enhanced Raman scattering (SERS) spectroelectrochemistry in the temperature interval from 12 to 72 °C at -0.600 and -1.000 V potentials. It was found that intensities of peptide bands decrease at temperatures above 30 °C with higher decrease slope at -1.000 V. Frequency of F12 mode (1004 cm(-1)) of non-surface-interactive phenylalanine residue was found to be insensitive to temperature variation at both studied electrode potentials, while frequency-temperature curves for surface-interactive groups (Amide-III, methylene) were found to be controlled by the potential. In particular, opposite frequency-temperature trends were detected for Amide-III (Am-III) mode indicating decrease in H-bonding interaction strength of amide C[double bond, length as m-dash]O and N-H groups above 38 °C for -0.600 V, and increase in H-bonding interaction strength between 12 and 72 °C for -1.000 V. Anomalous Am-III temperature-dependence of the frequency at -1.000 V was explained by temperature-induced transformation of a disordered secondary structure to a helix-like conformation. The potential-difference spectrum revealed interaction of methylene groups with Cu surface at sufficiently negative potential values because of the appearance of a soft C-H stretching band near 2825 cm(-1) and a broad band near 2904 cm(-1) assigned to vibration of a distal C-H bond of the surface-confined methylene group. Consequently, a rapid decrease in frequency of CH(2)-stretching band with temperature was observed at -1.000 V, while no essential frequency changes were detected for this mode at -0.600 V. The results show that electrode potential controls the temperature-dependence of the frequency for vibrations associated with surface-interactive molecular groups.

The majority of dorsal spinal cord gastrin releasing peptide is synthesized locally whereas neuromedin B is highly expressed in pain- and itch-sensing somatosensory neurons.

BACKGROUND: Itch is one of the major somatosensory modalities. Some recent findings have proposed that gastrin releasing peptide (Grp) is expressed in a subset of dorsal root ganglion (DRG) neurons and functions as a selective neurotransmitter for transferring itch information to spinal cord interneurons. However, expression data from public databases and earlier literatures indicate that Grp mRNA is only detected in dorsal spinal cord (dSC) whereas its family member neuromedin B (Nmb) is highly expressed in DRG neurons. These contradictory results argue that a thorough characterization of the expression of Grp and Nmb is warranted. FINDINGS: Grp mRNA is highly expressed in dSC but is barely detectable in DRGs of juvenile and adult mice. Anti-bombesin serum specifically recognizes Grp but not Nmb. Grp is present in a small number of small-diameter DRG neurons and in abundance in layers I and II of the spinal cord. The reduction of dSC Grp after dorsal root rhizotomy is significantly different from those of DRG derived markers but similar to that of a spinal cord neuronal marker. Double fluorescent in situ of Nmb and other molecular markers indicate that Nmb is highly and selectively expressed in nociceptive and itch-sensitive DRG neurons. CONCLUSION: The majority of dSC Grp is synthesized locally in dorsal spinal cord neurons. On the other hand, Nmb is highly expressed in pain- and itch-sensing DRG neurons. Our findings provide direct anatomic evidence that Grp could function locally in the dorsal spinal cord in addition to its roles in DRG neurons and that Nmb has potential roles in nociceptive and itch-sensitive neurons. These results will improve our understanding about roles of Grp and Nmb in mediating itch sensation.