Synapses
Nassir H. Sabah in Neuromuscular Fundamentals, 2020
Neuroactive peptides, also referred to as neuropeptides, can act as neurotransmitters when released by neurons, with some neuropeptides released by glia. Neuropeptides can act as hormones when secreted by glands into the blood stream. More than 100 neuropeptides have been identified and are involved in a wide range of brain functions including sensory perception, feeding behavior, emotions, social behavior, learning, and memory. Examples are oxytocin, vasopressin, substance P, and opioids, which include endorphins, these being endogenous compounds that mimic the action of morphine. However, the site of synthesis of neuropeptides, the type of vesicles in which they are stored, and the mechanism and site of exocytosis are quite different from those of the aforementioned neurotransmitters, which are often referred to as small-molecule neurotransmitters to distinguish them from neuropeptides.
Neuropeptides: Evidence for Central Pathways and Role in Cardiovascular Regulation
Irving H. Zucker, Joseph P. Gilmore in Reflex Control of the Circulation, 2020
A major problem in neuropeptide research is the lack of highly potent and selective receptor antagonists. With the exception of the opiates, where a potent and specific antagonist is available, only a few neuropeptides (e.g., SP) CRF has antagonists of modest selectivity and less than adequate potency. Furthermore, even with the advantage of naloxone as a potent and selective opiate antagonist, there are substantial difficulties in interpreting results with naloxone since the common pharmacological doses utilized block several types of opioid receptors that might have different and even opposite effects. Therefore, the lack of any appreciable effect of naloxone on baroreflexes may not necessarily indicate lack of opioid involvement in normal baroreceptor regulation; in fact, the difficulties at the present time to block the specific subtypes of the opioid receptor might have a role in this function.
Biological Basis of Behavior
Mohamed Ahmed Abd El-Hay in Understanding Psychology for Medicine and Nursing, 2019
Some neurotransmitters, such as acetylcholine and dopamine, can have both excitatory and inhibitory effects depending upon the type of receptors that are present. Neurotransmitters can be categorized as one of six types:Acetylcholine.Biogenic amines (monoamines): catecholamines (dopamine, norepinephrine), serotonin, and histamine.Amino acids: gamma-aminobutyric acid (GABA), glycine, glutamate, and aspartate.Neuropeptides: oxytocin, endorphins, vasopressin, etc.Purines: adenosine, ATP.Lipids and gases: nitric oxide, cannabinoids.
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
As neuropeptide function has some dependence on concentration [26], being able to reliably identify and quantify neuropeptides is necessary for understanding their function, especially as it relates to different biological states. A recent review has been published detailing mass spectrometry strategies applied to functional neuropeptidomics [27]. These functional studies are challenging, however, due to the low concentrations (as low as femtomolar) in vivo [26] of neuropeptides, highlighting the continual need for improved quantitative methods. Although MS is not inherently quantitative, its widespread application and growth in the -omic fields has led to the development of various strategies for accurate and sensitive quantitation. The quantification of neuropeptides has been achieved with label-free methods that allow analysis of the neuropeptides without modification and minimal sample loss [28]; a variety of labeling strategies that facilitate more reliable quantitation and greater throughput analyses [29]; and more recently, DIA workflows to increase reproducibility and enable detection of more low abundance analytes and thus deeper profiling of the neuropeptidome [22]. These methods are of course not the only quantitative methods for neuropeptidomics and others have been reported and summarized in other reviews [30,31].
Recently available and emerging therapeutic strategies for the acute and prophylactic management of cluster headache: a systematic review and expert opinion
Published in Expert Review of Neurotherapeutics, 2021
Andreas A. Argyriou, Michail Vikelis, Elisa Mantovani, Pantelis Litsardopoulos, Stefano Tamburin
For the development of a cluster attack, it is considered that yet unknown stimuli may trigger a series of events within the peripheral and CNS structures activating the mechanisms involved in the pathophysiology of CH. Substances targeting neuropeptides or their receptors within these cascades are of particular interest. For example, intravenous infusion of CGRP during an active phase was demonstrated to provoke a CH attack in eight out of nine patients, while outside the active phase none of the patients developed an attack following the infusion [32]. Furthermore, CH patients have higher plasma CGRP levels compared to both migraine patients and healthy controls [33], while CGRP levels are altered during CH attacks. These pieces of evidence bolster the key role that CGRP plays in CH pathogenesis and provide a rationale background for the use of CGRP functional blockade in its prevention.
Worms sleep: a perspective
Published in Journal of Neurogenetics, 2020
Each of the four worm sleep papers published in this edition of the Journal of Neurogenetics carries an important message. The van Buskirk lab paper (Goetting, et al, J. Neurogenet., in press) contributes to our understanding of the mechanism of SIS. They also describe a new trigger for SIS: skin injury, which is relevant to the human complaint of severe fatigue after an operation. The Bringmann lab paper (Busack et al, J. Neurogenet., in press) describes a method for long-term optogenetic manipulation of worms. Developing such methods is important because prior worm tools have been optimized for much shorter durations of manipulation and observations. The Nelson lab describes the role of orcokinins, neuropeptides conserved among molting animals, in regulating sleep (Honer et al, J. Neurogenet., in press). This study again emphasizes the important, but complex roles of neuropeptides in behavioral state modulation. Finally, the Hart lab paper reminds us that not all that stops moving is sleep and that we must remain self-skeptical as a field. They suggest that cessation of swimming is better explained by neuromuscular fatigue than by sleep (Schuch et al, J. Neurogenet., in press).
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