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Specific Arterial Disease
Published in Wilmer W Nichols, Michael F O'Rourke, Elazer R Edelman, Charalambos Vlachopoulos, McDonald's Blood Flow in Arteries, 2022
Headache in migraine is associated with and appears to be caused by dilatation of cerebral and extracerebral cranial arteries, sometimes with evidence of associated edema and inflammation (Iversen et al., 1990; Olesen, 1994; Raskin, 1994). In migraine with aura, headache with arterial vasodilatation follows a preliminary wave of “spreading depression” over the cerebral cortex. The mechanism is complex and not completely understood, but it appears to involve the release of serotonin from platelets at the beginning of the attack when vasoconstriction initially occurs. Sensory neuropeptides appear also to be involved and may be responsible for inflammation and the stimulation of pain receptors.
Neuropeptide Regulation of Ion Channels and Food Intake
Published in Tian-Le Xu, Long-Jun Wu, Nonclassical Ion Channels in the Nervous System, 2021
The main difference between classic small-molecule neurotransmitters and neuropeptides is that neuropeptides are synthesized and mainly packaged into large dense-core vesicles in the cell body while neurotransmitters are packaged in the synapse. Due to their location, synaptic vesicles release with smaller changes in intracellular calcium concentrations while dense core vesicles require higher intracellular calcium concentrations to release (van den Pol 2012). Neurons are often named for the primary neuropeptide or neurotransmitter they release. The actions of a neuron depend on its synaptic connectivity. In the control of feeding behaviors and energy metabolism, hypothalamic neuropeptide transmission plays a critical role in integrating nonhypothalamic and peripheral signals by activation of neuropeptide receptors which are metabotropic G-protein coupled receptors (GPCRs). Intracellular second messengers and G proteins are activated following neuropeptide binding to the coupled GPCRs, which opens or closes ion channels in the neuronal membrane to change the activity of the neurons and modulate the release of fast neurotransmitters (Figure 8.1). Thus, both GPCRs and ion channels on the membrane work together to modulate the neuronal activity when neuropeptides are released from feeding-related neurons in the hypothalamus and brainstem.
Perspective
Published in Sami I. Said, Proinflammatory and Antiinflammatory Peptides, 2020
Numerous biologically active peptides have been identified in mammalian and nonmammalian systems. Most of these peptides are synthesized and released by neuronal cells and hence are known as neuropeptides. As neurotransmitters in the central and peripheral nervous systems, neuropeptides are in a position to exert wide-ranging and important regulatory influences on almost all body functions. Peptides may also act as endocrine or neuroendocrine messengers, or by paracrine, neuro-crine, or autocrine mechanisms (1). Functions that are influenced by peptides include digestion, absorption, and gastrointestinal motility; metabolism; electrolyte balance; blood pressure, cardiac performance and blood flow to vital organs; vascular and nonvascular smooth muscle responses; cellular and humoral immune mechanisms; hormonal and neurohormonal secretion; and cell proliferation and differentiation. Peptides may also have antibacterial (2) and other activities.
Stimulant use for self-management of pain among safety-net patients with chronic non-cancer pain
Published in Substance Abuse, 2022
Cathleen M. Beliveau, Vanessa M. McMahan, Justine Arenander, Martin S. Angst, Margot Kushel, Andrea Torres, Glenn-Milo Santos, Phillip O. Coffin
Our findings reveal a potential relationship between neuropathic pain and stimulant use to treat pain. Specifically, we observed an association between the number of neuropathic pain attributes used by participants to describe their pain and their use of stimulants to treat pain. A qualitative study15 documented methamphetamine use to treat neuropathic pain in a small cohort of HIV-positive men. Notably, in our sample half of the HIV-positive participants who used stimulants used stimulants to treat pain, suggesting that HIV-associated pain, which is neuropathic in nature, may be one reason for stimulant use. The previously described role of the neuropeptide CART in regulating neuropathic pain further supports the potential benefit of these agents in neuropathic pain syndromes.17,18 Patients who have pain with a greater number of neuropathic characteristics may be more likely to use stimulants as a strategy to self-manage pain, although further study is needed.
The role of neuropeptide Y, orexin-A, and ghrelin in differentiating unipolar and bipolar depression: a preliminary study
Published in Nordic Journal of Psychiatry, 2022
Mehmet Ünler, İrem Ekmekçi Ertek, Nigar Afandiyeva, Mustafa Kavutçu, Nevzat Yüksel
Currently, the distinction between unipolar and bipolar patients in the depressive episode poses difficulties for clinicians, and there are no markers that can be used to differentiate these two clinical states. Recent studies of mood disorders investigating peripheral biomarkers have focused on three areas; cell growth, survival, and synaptic plasticity, including brain-derived neurotrophic factor; inflammation, particularly pro- and anti-inflammatory cytokines; and energy metabolism, particularly oxidative stress, and mitochondrial function [10]. In addition, studies on hypothalamic neuropeptides, which are involved in the regulation of vegetative functions such as appetite and sleep may also contribute to this area. Nevertheless, studies evaluating these neuropeptides in mood disorders have yielded contradictory and complex results due to methodological problems.
Developing mass spectrometry for the quantitative analysis of neuropeptides
Published in Expert Review of Proteomics, 2021
Christopher S. Sauer, Ashley Phetsanthad, Olga L. Riusech, Lingjun Li
This complexity inherent to all neuropeptidomic studies is exacerbated by the difficulties in determining possible neuropeptide sequences. Neuropeptides are produced by the select processing of precursor proteins (i.e. preprohormone) encoded within the genome [19]. These preprohormones contain a signaling sequence and the remaining prohormone. After cleavage of the signaling sequence, the prohormone is selectively and specifically cleaved by endopeptidases, such as various prohormone convertases, to produce several peptide sequences from a single precursor protein [20]. The peptides are then processed further and post-translationally modified to produce the bioactive neuropeptides [20]. The intricate pathways from genome to active neuropeptide, splice variants, and diversity of post-translational modifications lead to many possible peptide forms that are difficult to predict from genomics or even transcriptomics alone. This is compounded by the fact that many model organisms do not have a fully sequenced genome to use as a reliable starting point for predicting a full neuropeptide database, making neuropeptide studies even more challenging.