Migraine is among the most prevalent problems, and is very hard to deal with. Doctors and researchers have been perplexed for decades what exactly causes it and how can it be fought off. Migraine is signified by chronic headaches that recur either in days or weeks. The pain can be mild or intensified, varying from case to case. But no one is yet sure about the reason for this problem.
Suspecting that it is caused by high or low blood pressure, trauma, high level of stress, some deficiency or any such issue, people try to resolve it through medicines, exercise and change in diet etc. The pain may disappear for the time being but it returns with the same strength. This goes to show that there is some other reason, and the researchers believe that migraine is genetic disorder. Researchers, psychologists and doctors consider it illusive in nature as migraine cannot be diagnosed through X-rays, MRI, other means of brain imaging or any other physical symptoms. The only means of diagnosis is through the accounts of the patents about how often they face it, and how they feel in it.
The psychologists are now developing integrated solutions to attempt to treat migraine sufferers. They suggest lifestyle changes, diet alterations, pills as well as exercises to harness, if not eliminate, this widespread disorder. But the greatest developments are antimigraine drugs that can get patients rid of it.
Here are some important articles on migraine, published by Bentham Science Publishers:
Article by Disease on “Metabolic Disorders”
Introduction: The kynurenine pathway includes several neuroactive compounds, including kynurenic acid, picolinic acid, 3-hydroxykynurenine and quinolinic acid. The enzymatic cascade of the kynurenine pathway is tightly connected with the immune system, and may provide a link between the immune system and neurotransmission.
Main Areas Covered: Alterations in this cascade are associated with neurodegenerative, neurocognitive, autoimmune and psychiatric disorders, such as Parkinson’s disease, Huntington’s disease, Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis, migraine or schizophrenia.
Highlights: This review highlights the alterations in this metabolic pathway in the physiological aging process and in different disorders. A survey is also presented of therapeutic possibilities of influencing this metabolic route, which can be achieved through the use of synthetic kynurenic acid analogues, enzyme inhibitors or even nanotechnology.
Read more: http://www.eurekaselect.com/node/138027/article
Journal Title: Current Protein & Peptide Science
Article Title: Exploring New CGRP Family Peptides and their Receptors in Vertebrates
Author(s): Yoshio Takei, Maho Ogoshi and Shigenori Nobata
Vertebrates have expanded their habitats from aquatic to terrestrial environments, which has accompanied the evolution of cardiovascular and osmoregulatory hormones. Specifically, mammals have developed mechanisms to maintain high blood pressure and blood volume, while extant fishes have developed hypotensive and Na-extruding mechanisms to adapt to the marine environment where they underwent a vast diversification. The CGRP family is one of the hormone systems that decrease blood pressure and blood volume. Within the CGRP family of teleost fishes, we found that adrenomedullins (AMs) have diversified and five paralogs (AM1-5) form an independent subfamily. Based on this discovery in fishes, we found AM2 and AM5 in mammals. In mammalian species that have AM2 and/or AM5, the peptides assume greater importance in the case of pathophysiological disturbances in pressure and fluid balance such as hypertension and cardiac and renal failure. In addition, novel functions of AM peptides have been suggested by the discovery of AM2 and AM5 in mammals. Current research on the CGRP family is focused on the identification of new receptors for AM2/AM5 and the establishment of AM2 knockout mice, which will enable new developments in the basic and clinical research on this intriguing hormone family. Importantly, comparative fish studies can contribute to new developments in our understanding of the function of the AM peptides.
Article Title: Functions of Third Extracellular Loop and Helix 8 of Family B GPCRs Complexed with RAMPs and Characteristics of their Receptor Trafficking
Kenji Kuwasako, Debbie L Hay, Sayaka Nagata, Manabu Murakami, Kazuo Kitamura and Johji Kato
At least one of three receptor activity-modifying proteins (RAMP1, RAMP2 and RAMP3) can interact with 10 G protein-coupled receptors (GPCRs; nine Family B GPCRs and a Family C GPCR). All three RAMPs interact with the calcitonin (CT) receptor (CTR), the CTR-like receptor (CLR), the vasoactive intestinal peptide (VIP)/pituitary adenylate cyclase-activating polypeptide (PACAP) 1 (VPAC1) and the VPAC2 receptor, which are all Family B GPCRs. Three RAMPs enable CTR to function as three heterodimeric receptors for amylin, which is a feeding suppression peptide. These RAMPs also transport the CLR to the cell surface, where they function as a CT gene-related peptide (CGRP) receptor (CLR/RAMP1 heterodimer) and two adrenomedullin (AM) receptors (CLR/RAMP2 and CLR/RAMP3 heterodimers). CGRP and AM are potent hypotensive peptides that exert powerful protective effects against multi-organ damage. We recently reported that the third extracellular loop (ECL3) of CLR governs the activation of AM, but not CGRP, signaling in the three CLR/RAMP heterodimers. Furthermore, we showed that in the presence of RAMP2, the eighth helix (helix 8) in the proximal portion of the cytoplasmic C-terminal tail of the CLR, which is thought to be present in all family B GPCRs, participates in receptor signaling. In addition, we demonstrated that overexpression of GPCR kinase (GRK) 2, GRK3 and GRK4 enhances the AM-induced internalization of the CLR/RAMP2 heterodimer. In this review, we describe these studies and consider their implications for other Family B GPCRs that can interact with RAMPs.
For more details, visit: http://benthamscience.com/journal/abstracts.php?journalID=cpps&articleID=113130
Article Title: Adrenomedullin as a Potential Therapeutic Agent for Inflammatory Bowel Disease
Author(s): Shinya Ashizuka, Haruhiko Inatsu, Kyoko Inagaki-Ohara, Toshihiro Kita and Kazuo Kitamura
Adrenomedullin (AM) was originally isolated from human pheochromocytoma as a biologically active peptide with potent vasodilating action but is now known to exert a wide range of physiological effects, including cardiovascular protection, neovascularization, and apoptosis suppression. A variety of tissues, including the gastrointestinal tract, have been shown to constitutively produce AM. Pro-inflammatory cytokines, such as tumor necrosis factor-α and interleukin-1, and lipopolysaccharides, induce the production and secretion of AM. Conversely, AM induces the downregulation of inflammatory cytokines in cultured cells. Furthermore, AM downregulates inflammatory processes in a variety of different colitis models, including acetic acid-induced colitis and dextran sulfate sodium-induced colitis. AM exerts antiinflammatory and antibacterial effects and stimulates mucosal regeneration for the maintenance of the colonic epithelial barrier. Here, we describe the first use of AM to treat patients with refractory ulcerative colitis. The results strongly suggest that AM has potential as a new therapeutic agent for the treatment of refractory ulcerative colitis.
Article Title: Ectodomain Structures of the CGRP and AM Receptors
Seisuke Kusano and Shigeyuki Yokoyama
Receptor activity-modifying proteins (RAMPs) 1–3, which are classified as type I transmembrane proteins, serve as the partner proteins of several family B GPCRs for physiologically active peptides, including the calcitonin receptor- like receptor (CLR). The properties of the GPCRs are defined by the RAMP and peptide ligand combination. The CLR•RAMP1 heterodimer functions mainly as the calcitonin gene-related peptide (CGRP) receptor, while the CLR•RAMP2 and CLR•RAMP3 heterodimers primarily function as the adrenomedullin 1 and adrenomedullin 2 (AM1 and AM2) receptors, respectively. The crystal structures of the RAMP1 and RAMP2 ectodomains exhibited three-helix bundles, and those of their complexes with the N-terminal extracellular domain of CLR revealed how the two ectodomains associate to form the CGRP and AM1 receptors, respectively. On this structural framework, the various intermolecular interactions of CLR with RAMP1 and RAMP2 result in the distinct shapes of the putative ligand-binding sites, where several residues are uniquely presented. Therefore, the differences in the shapes and the presented residues of the binding sites determine the specificities of the receptors to either CGRP or AM. These structural features of the ectodomains are consistent with mutagenesis results, and are useful to further examine the binding modes of the peptide ligands to the full-length CGRP and AM1 receptors.
Article Title: Insulin Resistance-Induced Hypertension and a Role of Perivascular CGRPergic Nerves
Author(s): Shingo Takatori, Yoshito Zamami, Narumi Hashikawa-Hobara and Hiromu Kawasaki
Insulin resistance is defined as a preliminary step of type 2 diabetes mellitus with decreased insulin action evoked by continuous postprandial hyperglycemia, which is provoked by high fat and calories dieting, a lack of physical activity and obesity. In the early phase of type 2 diabetes mellitus, patients have a hyperinsulinemia to compensate deficient insulin action by increased secretion from the pancreas to maintain euglycemia. Then, pancreatic β cells progressively decrease secretion function, resulting in the development of diabetes mellitus with decreased serum insulin levels. Accumulating evidences show that insulin resistance is associated with hypertension. However, the mechanisms underlying hypertension associated with type 2 diabetes mellitus have still unknown. Therefore, to elucidate the mechanisms of insulin resistance-induced hypertension, we investigated that the effects of hyperinsulinemia or hyperglycemia on vascular responses mediated by perivascular nerves including sympathetic adrenergic nerves and calcitonin gene-related peptide (CGRP)-containing nerves (CGRPergic nerves). In this article, we show evidence that insulin resistance-induced hypertension could be resulted from increased density and function of sympathetic nerve, and decreased density and function of CGRPergic nerves. Furthermore, our findings provide a new insight into the research of therapeutic drugs for insulin resistance- induced hypertension.