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  1. Fulltext A New Pedestrian Crossing Level of Service (PCLOS) Method for Promoting Safe Pedestrian Crossing in Urban Areas
    Ahmed T, Moeinaddini M, Almoshaogeh M, Jamal A, Nawaz I, Alharbi F
    Int J Environ Res Public Health, 2021 08 20;18(16).
    PMID: 34444563 DOI: 10.3390/ijerph18168813
    Crosswalks are critical locations in the urban transport network that need to be designed carefully as pedestrians are directly exposed to vehicular traffic. Although various methods are available to evaluate the level of service (LOS) at pedestrian crossings, pedestrian crossing facilities are frequently ignored in assessing crosswalk conditions. This study attempts to provide a comprehensive framework for evaluating crosswalks based on several essential indicators adopted from different guidelines. A new pedestrian crossing level of service (PCLOS) method is introduced in this research, with an aimto promote safe and sustainable operations at such locations. The new PCLOS employs an analytical point system to compare existing street crossing conditions to the guidelines' standards, taking into account the scores and coefficients of the indicators. The quantitative scores and coefficients of indicators are assigned based on field observations and respondent opinions. The method was tested to evaluate four pedestrian crosswalks in the city of Putrajaya, Malaysia. A total of 17 indicators were selected for the study after a comprehensive literature review. Survey results show that the provision of a zebra crossing was the most critical indicator at the pedestrian crossings, while drainage near crosswalks was regarded as the least important. Four indicators had a coefficient value above 4, indicating that these are very critical pedestrian crossing facilities and significantly impact the calculation of LOS for pedestrian crossings. Four crosswalks were evaluated using the proposed method in Putrajaya, Malaysia. The crosswalk at the Ministry of Domestic Trade Putrajaya got the "PCLOS A". In contrast, the midblock crossing in front of the Putrajaya Corporation was graded "PCLOS C". While the remaining two crosswalks were graded as "PCLOS B" crosswalks. Based on the assigned PCLOS grade, the proposed method could also assist in identifying current design and operation issues in existing pedestrian crossings and providing sound policy recommendations for improvements to ensure pedestrian safety.
    Matched MeSH terms: Neuropeptides*
  2. RFamide peptides as mediators in environmental control of GnRH neurons
    Parhar I, Ogawa S, Kitahashi T
    Prog. Neurobiol., 2012 Aug;98(2):176-96.
    PMID: 22684005 DOI: 10.1016/j.pneurobio.2012.05.011
    Hypothalamic gonadotropin-releasing hormone (GnRH) is a key hormone for reproductive functions in vertebrates and non-vertebrates. Although GnRH neuronal system is regulated by several factors such as steroids, neurotransmitters and neuropeptides, it is not fully understood how environmental signals control the GnRH neuronal system. RFamide peptides, members of peptides possessing an Arg-Phe-NH(2) motif at their C-terminus, have recently been characterized as major regulators of GnRH neurons. In particular, two key RFamide peptides, kisspeptin and gonadotropin-inhibitory hormone (GnIH), are emerging as important regulators of the reproductive axis. Kisspeptin acts as the accelerator, directly driving GnRH neurons, whereas GnIH acts as the restraint. In addition, other RFamide peptides such as prolactin-releasing peptide (PrRP), PQRFa peptide, 26RFa/QRFP are also known to control reproduction. These RFamide peptides are regulated by environmental factors such as photoperiods, steroid hormones, metabolic signals, and stress. How environmental signals are integrated by RFamide peptides to regulate reproduction through the GnRH neurons?
    Matched MeSH terms: Neuropeptides/physiology*
  3. Gonadotropin-inhibitory hormone mediates behavioral stress responses
    Ubuka T, Parhar IS, Tsutsui K
    Gen Comp Endocrinol, 2018 09 01;265:202-206.
    PMID: 29510150 DOI: 10.1016/j.ygcen.2018.03.004
    Gonadotropin-inhibitory hormone (GnIH) is an inhibitor of the hypothalamic-pituitary-gonadal (HPG) axis. GnIH is also called RFamide-related peptide (RFRP) as GnIH peptides have a characteristic C-terminal LPXRFiamide (X = L or Q) sequence. GnIH is thought to be the mediator of stress by negatively regulating the HPG axis as various stressors increase GnIH mRNA, GnIH peptide or GnIH neuronal activity. On the other hand, GnIH may also mediate behavioral stress responses as GnIH neuronal fibers and GnIH receptors are widely located in the limbic system of telencephalon, diencephalon and midbrain area. Previous studies have shown that intracerebroventricular (i.c.v.) administration of GnIH (RFRP) blocks morphine-induced analgesia in hot plate and formalin injection tests in rats suggesting that GnIH increases sensitivity to pain. GnIH (RFRP) also increases anxiety-like behavior in rats. RNA interference of GnIH gene (GnIH RNAi) increases locomotor activity of white-crowned sparrow and Japanese quail and i.c.v. administration of GnIH decreases GnIH RNAi induced locomotor activity. It was further shown that i.c.v. administration of GnIH (RFRP) decreases aggressive behavior in male quail and sexual behavior in male rats, female white-crowned sparrow and female hamsters. These results suggest that GnIH decreases threat to homeostasis of the organism by increasing pain sensitivity, anxiety and decreasing locomotor activity, aggressive behavior and sexual behavior. GnIH may also mediate the effect of stress on behavior.
    Matched MeSH terms: Neuropeptides/pharmacology*
  4. Fulltext RACK-1 overexpression protects against goniothalamin-induced cell death
    Inayat-Hussain SH, Wong LT, Chan KM, Rajab NF, Din LB, Harun R, et al.
    Toxicol Lett, 2009 Dec 15;191(2-3):118-22.
    PMID: 19698770 DOI: 10.1016/j.toxlet.2009.08.012
    Goniothalamin, a styryllactone, has been shown to induce cytotoxicity via apoptosis in several tumor cell lines. In this study, we have examined the potential role of several genes, which were stably transfected into T-cell lines and which regulate apoptosis in different ways, on goniothalamin-induced cell death. Overexpression of full-length receptor for activated protein C-kinase 1 (RACK-1) and pc3n3, which up-regulates endogenous RACK-1, in both Jurkat and W7.2 T cells resulted in inhibition of goniothalamin-induced cell death as assessed by MTT and clonogenic assays. However, overexpression of rFau (antisense sequence to Finkel-Biskis-Reilly murine sarcoma virus-associated ubiquitously expressed gene) in W7.2 cells did not confer resistance to goniothalamin-induced cell death. Etoposide, a clinically used cytotoxic agent, was equipotent in causing cytotoxicity in all the stable transfectants. Assessment of DNA damage by Comet assay revealed goniothalamin-induced DNA strand breaks as early as 1 h in vector control but this effect was inhibited in RACK-1 and pc3n3 stably transfected W7.2 cells. This data demonstrate that RACK-1 plays a crucial role in regulating cell death signalling pathways induced by goniothalamin.
    Matched MeSH terms: Neuropeptides/biosynthesis; Neuropeptides/genetics; Neuropeptides/physiology*
  5. LPXRFa, the piscine ortholog of GnIH, and LPXRF receptor positively regulate gonadotropin secretion in Tilapia (Oreochromis niloticus)
    Biran J, Golan M, Mizrahi N, Ogawa S, Parhar IS, Levavi-Sivan B
    Endocrinology, 2014 Nov;155(11):4391-401.
    PMID: 25144920 DOI: 10.1210/en.2013-2047
    LPXRFamide (LPXRFa) peptides have been characterized for their ability to inhibit gonadotropin (GTH) release in birds and stimulate growth hormone (GH) release in frogs. However, their involvement in regulating the reproductive hypothalamo-pituitary-gonadal axis in mammals and fish is inconclusive. To study the role of LPXRFa peptides in the regulation of GTH secretion, we cloned tilapia LPXRFa and LPXRF receptor (LPXRF-R). Processing of the tilapia preproLPXRFa liberated three mature LPXRFa peptides that varied in size and post-translational modifications. Phylogenetic analysis of LPXRFa and the closely related RFamide peptide PQRFa showed clear clustering of each peptide sequence with its orthologs from various vertebrates. Signal-transduction analysis of the tilapia LPXRF-R in COS-7 cells showed clear stimulation of CRE-dependent luciferase activity, whereas the human NPFFR1 showed suppression of forskolin-induced CRE-dependent activity in this system. Administration of the tilapia pyroglutaminated LPXRFa-2 peptide to primary cell culture of tilapia pituitaries, or to reproductive female tilapia by ip injection, positively regulated both LH and FSH release in vivo and in vitro. Using double-labeled fluorescent in-situ hybridization and immunofluorescence, βLH cells were found to co-express both tilapia lpxrf and tilapia lpxrf-r mRNA, whereas some of the βFSH cells coexpressed only lpxrf-r mRNA. No coexpression of tilapia lpxrf-r was identified in GH-positive cells. These findings suggest that the LPXRFa system is a potent positive regulator of the reproductive neuroendocrine axis of tilapia.
    Matched MeSH terms: Neuropeptides/pharmacology; Neuropeptides/physiology*
  6. Fulltext Reproductive Neuroendocrine Pathways of Social Behavior
    Parhar IS, Ogawa S, Ubuka T
    Front Endocrinol (Lausanne), 2016;7:28.
    PMID: 27065948 DOI: 10.3389/fendo.2016.00028
    Social behaviors are key components of reproduction, because they are essential for successful fertilization. Social behaviors, such as courtship, mating, and aggression, are strongly associated with sex steroids, such as testosterone, estradiol, and progesterone. Secretion of sex steroids from the gonads is regulated by the hypothalamus-pituitary-gonadal (HPG) axis in vertebrates. Gonadotropin-releasing hormone (GnRH) is a pivotal hypothalamic neuropeptide that stimulates gonadotropin release from the pituitary. In recent years, the role of neuropeptides containing the C-terminal Arg-Phe-NH2 (RFamide peptides) has been emphasized in vertebrate reproduction. In particular, two key RFamide peptides, kisspeptin and gonadotropin-inhibitory hormone (GnIH), emerged as critical accelerator and suppressor of gonadotropin secretion. Kisspeptin stimulates GnRH release by directly acting on GnRH neurons, whereas GnIH inhibits gonadotropin release by inhibiting kisspeptin, GnRH neurons, or pituitary gonadotropes. These neuropeptides can regulate social behavior by regulating the HPG axis. However, distribution of neuronal fibers of GnRH, kisspeptin, and GnIH neurons is not limited within the hypothalamus, and the existence of extrahypothalamic neuronal fibers suggests direct control of social behavior within the brain. It has traditionally been shown that central administration of GnRH can stimulate female sexual behavior in rats. Recently, it was shown that Kiss1, one of the paralogs of kisspeptin peptide family, regulates fear responses in zebrafish and GnIH inhibits sociosexual behavior in birds. Here, we highlight recent findings regarding the role of GnRH, kisspeptin, and GnIH in the regulation of social behaviors in fish, birds, and mammals and discuss their importance in future biological and biomedical research.
    Matched MeSH terms: Neuropeptides
  7. Fulltext A Journey through the Gonadotropin-Inhibitory Hormone System of Fish
    Muñoz-Cueto JA, Paullada-Salmerón JA, Aliaga-Guerrero M, Cowan ME, Parhar IS, Ubuka T
    Front Endocrinol (Lausanne), 2017;8:285.
    PMID: 29163357 DOI: 10.3389/fendo.2017.00285
    Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that belongs to the RFamide peptide family and was first identified in the quail brain. From the discovery of avian GnIH, orthologous GnIH peptides have been reported in a variety of vertebrates, including mammals, amphibians, teleosts and agnathans, but also in protochordates. It has been clearly established that GnIH suppresses reproduction in avian and mammalian species through its inhibitory actions on brain GnRH and pituitary gonadotropins. In addition, GnIH also appears to be involved in the regulation of feeding, growth, stress response, heart function and social behavior. These actions are mediated via G protein-coupled GnIH receptors (GnIH-Rs), of which two different subtypes, GPR147 and GPR74, have been described to date. With around 30,000 species, fish represent more than one-half of the total number of recognized living vertebrate species. In addition to this impressive biological diversity, fish are relevant because they include model species with scientific and clinical interest as well as many exploited species with economic importance. In spite of this, the study of GnIH and its physiological effects on reproduction and other physiological processes has only been approached in a few fish species, and results obtained are in some cases conflicting. In this review, we summarize the information available in the literature on GnIH sequences identified in fish, the distribution of GnIH and GnIH-Rs in central and peripheral tissues, the physiological actions of GnIH on the reproductive brain-pituitary-gonadal axis, as well as other reported effects of this neuropeptide, and existing knowledge on the regulatory mechanisms of GnIH in fish.
    Matched MeSH terms: Neuropeptides
  8. Fulltext Dual Actions of Mammalian and Piscine Gonadotropin-Inhibitory Hormones, RFamide-Related Peptides and LPXRFamide Peptides, in the Hypothalamic-Pituitary-Gonadal Axis
    Ubuka T, Parhar I
    Front Endocrinol (Lausanne), 2017;8:377.
    PMID: 29375482 DOI: 10.3389/fendo.2017.00377
    Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that decreases gonadotropin synthesis and release by directly acting on the gonadotrope or by decreasing the activity of gonadotropin-releasing hormone (GnRH) neurons. GnIH is also called RFamide-related peptide in mammals or LPXRFamide peptide in fishes due to its characteristic C-terminal structure. The primary receptor for GnIH is GPR147 that inhibits cAMP production in target cells. Although most of the studies in mammals, birds, and fish have shown the inhibitory action of GnIH in the hypothalamic-pituitary-gonadal (HPG) axis, several in vivo studies in mammals and many in vivo and in vitro studies in fish have shown its stimulatory action. In mouse, although the firing rate of the majority of GnRH neurons is decreased, a small population of GnRH neurons is stimulated by GnIH. In hamsters, GnIH inhibits luteinizing hormone (LH) release in the breeding season when their endogenous LH level is high but stimulates LH release in non-breeding season when their LH level is basal. Besides different effects of GnIH on the HPG axis depending on the reproductive stages in fish, higher concentration or longer duration of GnIH administration can stimulate their HPG axis. These results suggest that GnIH action in the HPG axis is modulated by sex-steroid concentration, the action of neuroestrogen synthesized by the activity of aromatase stimulated by GnIH, estrogen membrane receptor, heteromerization and internalization of GnIH, GnRH, and estrogen membrane receptors. The inhibitory and stimulatory action of GnIH in the HPG axis may have a physiological role to maintain reproductive homeostasis according to developmental and reproductive stages.
    Matched MeSH terms: Neuropeptides
  9. Lipopolysaccharide reduces gonadotrophin-releasing hormone (GnRH) gene expression: role of RFamide-related peptide-3 and kisspeptin
    Lee CY, Li S, Li XF, Stalker DAE, Cooke C, Shao B, et al.
    Reprod Fertil Dev, 2019 May;31(6):1134-1143.
    PMID: 30922440 DOI: 10.1071/RD18277
    RFamide-related peptide (RFRP)-3 reduces luteinising hormone (LH) secretion in rodents. Stress has been shown to upregulate the expression of the RFRP gene (Rfrp) with a concomitant reduction in LH secretion, but an effect on expression of the gonadotrophin-releasing hormone (GnRH) gene (Gnrh1) has not been shown. We hypothesised that lipopolysaccharide (LPS)-induced stress affects expression of Rfrp, the gene for kisspeptin (Kiss1) and/or Gnrh1, leading to suppression of LH levels in rats. Intracerebroventricular injections of RFRP-3 (0.1, 1, 5 nmol) or i.v. LPS (15μgkg-1) reduced LH levels. Doses of 1 and 5 nmol RFRP-3 were then administered to analyse gene expression by in situ hybridisation. RFRP-3 (5 nmol) had no effect on Gnrh1 or Kiss1 expression. LPS stress reduced GnRH and Kiss1 expression, without affecting Rfrp1 expression. These data indicate that LPS stress directly or indirectly reduces Gnrh1 expression, but this is unlikely to be due to a change in Rfrp1 expression.
    Matched MeSH terms: Neuropeptides/pharmacology*
  10. Distribution of Kiss2 receptor in the brain and its localization in neuroendocrine cells in the zebrafish
    Ogawa S, Sivalingam M, Anthonysamy R, Parhar IS
    Cell Tissue Res, 2020 Feb;379(2):349-372.
    PMID: 31471710 DOI: 10.1007/s00441-019-03089-5
    Kisspeptin is a hypothalamic neuropeptide, which acts directly on gonadotropin-releasing hormone (GnRH)-secreting neurons via its cognate receptor (GPR54 or Kiss-R) to stimulate GnRH secretion in mammals. In non-mammalian vertebrates, there are multiple kisspeptins (Kiss1 and Kiss2) and Kiss-R types. Recent gene knockout studies have demonstrated that fish kisspeptin systems are not essential in the regulation of reproduction. Studying the detailed distribution of kisspeptin receptor in the brain and pituitary is important for understanding the multiple action sites and potential functions of the kisspeptin system. In the present study, we generated a specific antibody against zebrafish Kiss2-R (=Kiss1Ra/GPR54-1/Kiss-R2/KissR3) and examined its distribution in the brain and pituitary. Kiss2-R-immunoreactive cell bodies are widely distributed in the brain including in the dorsal telencephalon, preoptic area, hypothalamus, optic tectum, and in the hindbrain regions. Double-labeling showed that not all but a subset of preoptic GnRH3 neurons expresses Kiss2-R, while Kiss2-R is expressed in most of the olfactory GnRH3 neurons. In the posterior preoptic region, Kiss2-R immunoreactivity was seen in vasotocin cells. In the pituitary, Kiss2-R immunoreactivity was seen in corticotropes, but not in gonadotropes. The results in this study suggest that Kiss2 and Kiss2-R signaling directly serve non-reproductive functions and indirectly subserve reproductive functions in teleosts.
    Matched MeSH terms: Neuropeptides/metabolism
  11. Fulltext Neuropeptide S-initiated sequential cascade mediated by OX1, NK1, mGlu5 and CB1 receptors: a pivotal role in stress-induced analgesia
    Lee MT, Chiu YT, Chiu YC, Hor CC, Lee HJ, Guerrini R, et al.
    J Biomed Sci, 2020 Jan 09;27(1):7.
    PMID: 31915019 DOI: 10.1186/s12929-019-0590-1
    BACKGROUND: Stress-induced analgesia (SIA) is an evolutionarily conserved phenomenon during stress. Neuropeptide S (NPS), orexins, substance P, glutamate and endocannabinoids are known to be involved in stress and/or SIA, however their causal links remain unclear. Here, we reveal an unprecedented sequential cascade involving these mediators in the lateral hypothalamus (LH) and ventrolateral periaqueductal gray (vlPAG) using a restraint stress-induced SIA model.

    METHODS: Male C57BL/6 mice of 8-12 week-old were subjected to intra-cerebroventricular (i.c.v.) and/or intra-vlPAG (i.pag.) microinjection of NPS, orexin-A or substance P alone or in combination with selective antagonists of NPS receptors (NPSRs), OX1 receptors (OX1Rs), NK1 receptors (NK1Rs), mGlu5 receptors (mGlu5Rs) and CB1 receptors (CB1Rs), respectively. Antinociceptive effects of these mediators were evaluated via the hot-plate test. SIA in mice was induced by a 30-min restraint stress. NPS levels in the LH and substance P levels in vlPAG homogenates were compared in restrained and unrestrained mice.

    RESULTS: NPS (i.c.v., but not i.pag.) induced antinociception. This effect was prevented by i.c.v. blockade of NPSRs. Substance P (i.pag.) and orexin-A (i.pag.) also induced antinociception. Substance P (i.pag.)-induced antinociception was prevented by i.pag. Blockade of NK1Rs, mGlu5Rs or CB1Rs. Orexin-A (i.pag.)-induced antinociception has been shown previously to be prevented by i.pag. blockade of OX1Rs or CB1Rs, and here was prevented by NK1R or mGlu5R antagonist (i.pag.). NPS (i.c.v.)-induced antinociception was prevented by i.pag. blockade of OX1Rs, NK1Rs, mGlu5Rs or CB1Rs. SIA has been previously shown to be prevented by i.pag. blockade of OX1Rs or CB1Rs. Here, we found that SIA was also prevented by i.c.v. blockade of NPSRs or i.pag. blockade of NK1Rs or mGlu5Rs. Restrained mice had higher levels of NPS in the LH and substance P in the vlPAG than unrestrained mice.

    CONCLUSIONS: These results suggest that, during stress, NPS is released and activates LH orexin neurons via NPSRs, releasing orexins in the vlPAG. Orexins then activate OX1Rs on substance P-containing neurons in the vlPAG to release substance P that subsequently. Activates NK1Rs on glutamatergic neurons to release glutamate. Glutamate then activates perisynaptic mGlu5Rs to initiate the endocannabinoid retrograde inhibition of GABAergic transmission in the vlPAG, leading to analgesia.

    Matched MeSH terms: Neuropeptides/metabolism*
  12. Fulltext Selected neuropeptide genes show genetic differentiation between Africans and non-Africans
    Tai KY, Wong K, Aghakhanian F, Parhar IS, Dhaliwal J, Ayub Q
    BMC Genet, 2020 03 14;21(1):31.
    PMID: 32171244 DOI: 10.1186/s12863-020-0835-8
    BACKGROUND: Publicly available genome data provides valuable information on the genetic variation patterns across different modern human populations. Neuropeptide genes are crucial to the nervous, immune, endocrine system, and physiological homeostasis as they play an essential role in communicating information in neuronal functions. It remains unclear how evolutionary forces, such as natural selection and random genetic drift, have affected neuropeptide genes among human populations. To date, there are over 100 known human neuropeptides from the over 1000 predicted peptides encoded in the genome. The purpose of this study is to analyze and explore the genetic variation in continental human populations across all known neuropeptide genes by examining highly differentiated SNPs between African and non-African populations.

    RESULTS: We identified a total of 644,225 SNPs in 131 neuropeptide genes in 6 worldwide population groups from a public database. Of these, 5163 SNPs that had ΔDAF |(African - non-African)| ≥ 0.20 were identified and fully annotated. A total of 20 outlier SNPs that included 19 missense SNPs with a moderate impact and one stop lost SNP with high impact, were identified in 16 neuropeptide genes. Our results indicate that an overall strong population differentiation was observed in the non-African populations that had a higher derived allele frequency for 15/20 of those SNPs. Highly differentiated SNPs in four genes were particularly striking: NPPA (rs5065) with high impact stop lost variant; CHGB (rs6085324, rs236150, rs236152, rs742710 and rs742711) with multiple moderate impact missense variants; IGF2 (rs10770125) and INS (rs3842753) with moderate impact missense variants that are in linkage disequilibrium. Phenotype and disease associations of these differentiated SNPs indicated their association with hypertension and diabetes and highlighted the pleiotropic effects of these neuropeptides and their role in maintaining physiological homeostasis in humans.

    CONCLUSIONS: We compiled a list of 131 human neuropeptide genes from multiple databases and literature survey. We detect significant population differentiation in the derived allele frequencies of variants in several neuropeptide genes in African and non-African populations. The results highlights SNPs in these genes that may also contribute to population disparities in prevalence of diseases such as hypertension and diabetes.

    Matched MeSH terms: Neuropeptides/genetics*
  13. Fulltext Evolution of Structural and Functional Diversity of Spexin in Mammalian and Non-mammalian Vertebrate Species
    Lim CH, Lee MYM, Soga T, Parhar I
    Front Endocrinol (Lausanne), 2019;10:379.
    PMID: 31275244 DOI: 10.3389/fendo.2019.00379
    Spexin (SPX) is a novel neuropeptide, which was first identified in the human genome using bioinformatics. Since then, orthologs of human SPX have been identified in mammalian and non-mammalian vertebrates. The mature sequence of SPX, NWTPQAMLYLKGAQ, is evolutionally conserved across vertebrate species, with some variations in teleost species where Ala at position 13 is substituted by Thr. In mammals, the gene structure of SPX comprises six exons and five introns, however, variation exists within non-mammalian species, goldfish and zebrafish having five exons while grouper has six exons. Phylogenetic and synteny analysis, reveal that SPX is grouped together with two neuropeptides, kisspeptin (KISS) and galanin (GAL) as a family of peptides with a common evolutionary ancestor. A paralog of SPX, termed SPX2 has been identified in non-mammalians but not in the mammalian genome. Ligand-receptor interaction study also shows that SPX acts as a ligand for GAL receptor 2 (2a and 2b in non-mammalian vertebrates) and 3. SPX acts as a neuromodulator with multiple central and peripheral physiological roles in the regulation of insulin release, fat metabolism, feeding behavior, and reproduction. Collectively, this review provides a comprehensive overview of the evolutionary diversity as well as molecular and physiological roles of SPX in mammalian and non-mammalian vertebrate species.
    Matched MeSH terms: Neuropeptides
  14. Restless legs syndrome: pathophysiology and modern management
    Nagandla K, De S
    Postgrad Med J, 2013 Jul;89(1053):402-10.
    PMID: 23524988 DOI: 10.1136/postgradmedj-2012-131634
    Restless legs syndrome (RLS) is a common sensory motor neurological disorder that is characterised by an irresistible urge to move the legs that significantly affects the quality of life of the patient. Prevalence in the general population is 5-25% and it is twice as prevalent in women as in men. RLS is the most common movement disorder in pregnancy with a fourfold increased risk of developing this disorder later in life. The pathophysiology of RLS is centred on dopaminergic dysfunction, reduced central nervous system iron, genetic linkages, or alteration in neurotransmitters such as hypocretins, endorphins levels and immune dysfunction and inflammatory mechanisms. With the emergence of new evidence, there are changes to the previous treatment recommendations for RLS. There is sufficient evidence to conclude that dopamine agonists such as rotigotine transdermal patch, pramipexole, ropinirole, gabapentin enacarbil, pregabalin and gabapentin are effective in the short-term treatment of RLS and rotigotine, followed by gabapentin enacarbil, ropinirole, pramipexole and gabapentin for long-term treatment. Based on expert consensus, the recommendation for daily RLS is dopamine agonists or gabapentin or low-potency opioids. Levodopa is less preferred for treating daily RLS due to its high risk of augmentation. For intermittent RLS, it is levodopa or dopamine agonists or low-potency opioids or benzodiazepines. For refractory RLS, the choice is to change to gabapentin or a different dopamine agonist, addition of a second agent like gabapentin or benzodiazepine to the existing drug or changing to a high-potency opioid or tramadol. Medications with safety record in pregnancy include opioids and antiepileptics such as carbamazepine and gabapentin. There are concerns that patients with RLS are at risk for metabolic deregulation, autonomic dysfunction and cardiovascular morbidity. However, a recent study concluded that RLS is not associated with increased risk of cardiovascular complications.
    Matched MeSH terms: Neuropeptides/blood
  15. Citalopram (antidepressant) administration causes sexual dysfunction in male mice through RF-amide related peptide in the dorsomedial hypothalamus
    Soga T, Wong DW, Clarke IJ, Parhar IS
    Neuropharmacology, 2010 Jul-Aug;59(1-2):77-85.
    PMID: 20381503 DOI: 10.1016/j.neuropharm.2010.03.018
    Citalopram is the most potent selective serotonin reuptake inhibitor (SSRI) which is used as an antidepressant but causes sexual dysfunction. Whether citalopram induced sexual dysfunction is a result of gonadotropin-releasing hormone (GnRH), kisspeptin or RF-amide related peptide (RFRP) alteration is unknown. In this study, we tested mice for sexual behavior after vehicle (0.9% NaCl) and citalopram treatment (5 mg/kg) daily for 1 day (acute) and 21 or 28 days (chronic). Effects of acute and chronic treatments on neuronal numbers and mRNA expression of GnRH, kisspeptin and RFRP were measured. In addition, RFRP fiber projections to preoptic (POA)-GnRH neurons were analyzed using double-label immunohistochemistry. The expression of 14 different serotonin receptor types mRNA was examined in immunostained laser dissected single RFRP neurons in the dorsomedial hypothalamus (DMH), however only 11 receptors types were identified. Acute citalopram treatment did not affect sexual behavior, whereas, the total duration of intromission was reduced with chronic treatment. There was no effect in the expression of kisspeptin (neuronal numbers and mRNA) in the anteroventral periventricular nucleus and the arcuate nucleus and expression of GnRH (neuronal numbers and mRNA) in the POA after citalopram treatment. However, RFRP neuronal numbers in the DMH and fiber projections to the POA were significantly increased after chronic citalopram treatment, which suggests citalopram induced inhibition of sexual behavior involves the modulation of RFRP through serotonin receptors in the DMH.
    Matched MeSH terms: Neuropeptides/metabolism*
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