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Neuronal Regulation of the Immune System in Cardiovascular Diseases
Published in Shyam S. Bansal, Immune Cells, Inflammation, and Cardiovascular Diseases, 2022
Daniela Carnevale, Giuseppe Lembo, Marialuisa Perrotta, Lorenzo Carnevale
The circumventricular organs (CVOs), located around the third and fourth ventricles, are particular brain regions characterized by a leaky blood–brain barrier (BBB) and dense vascularization (Ballabh, Braun, & Nedergaard, 2004). These specialized areas are points of communication between the blood, the brain parenchyma, and the cerebrospinal fluid. The peripheral nervous system (PNS) connects the CNS to peripheral tissues and is mainly organized in two branches comprising the somatic and autonomic systems. Each of these systems further consists of two arms of sensory or afferent neurons – transporting the information from the periphery to the CNS – and motor or efferent neurons, delivering responses toward the effector tissues (Reardon et al., 2018). Additionally, the humoral route regulated by the hypothalamus-pituitary-adrenal axis provides further control of neuroimmune communication in health and disease.
Neurons
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The adjectives afferent and efferent (Section 1.2.1) are sometimes applied to neurons. An afferent neuron to a given region inputs APs to that region, whereas an efferent neuron outputs APs from that region.
Motor Function and ControlDescending Tracts
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
A reflex can be defined as an automatic or involuntary stereotype response to a stimulus mediated by a receptor, an afferent and efferent pathway and an effector organ. The reflex pathway generally consists of a receptor and an afferent neuron and is integrated by interneurons in the spinal cord. The final common efferent path is a motor neuron to the effector organ. Spinal cord ventral horn motor neurons may be either α motor neurons (14 μm in diameter and rapid conduction velocity) or γ motor neurons (5 μm in diameter and slower conduction velocity). There are also interneurons, which are highly excitable and may have high spontaneous firing rates. The Renshaw cell is a special interneuron that receives collateral branches of motor neuron axons. The Renshaw cell provides inhibitory connections with the same or neighbouring motor neurons via its own axons.
The triple function of the capsaicin-sensitive sensory neurons: In memoriam János Szolcsányi
Published in Temperature, 2023
Erika Pintér, Zsuzsanna Helyes, Éva Szőke, Kata Bölcskei, Angéla Kecskés, Gábor Pethő
Prof. János Szolcsányi spent 60 years studying the properties of capsaicin-sensitive sensory neurons. The existence of the latter subpopulation of primary afferent neurons itself has been adopted by the scientific community as a result of his extensive and fruitful research activity. His research group has provided substantial evidence for the triple function of the peptidergic subgroup of the capsaicin-sensitive sensory neurons including classical afferent function, local efferent tissue responses and remote, hormone-like anti-inflammatory and antinociceptive actions. This latter phenomenon was named “sensocrine” function by his own words. These discoveries have, and in the future certainly will have, broad implications for studying pathophysiological regulation of inflammation and pain as well as for the development of novel analgesic drugs acting directly on peripheral nociceptors. The immunohistological pictures shown below demonstrate co-localization of TRPV1 and TRPA1 channels, CGRP and SOM in primary sensory neurons from the L4 dorsal root ganglion of the rat using the RNAscope method (Figure 5). These four proteins/peptides are not only characteristic markers of these neurons but also cornerstones of the splendid research work performed by János Szolcsányi and his coworkers.
Communication between the gut microbiota and peripheral nervous system in health and chronic disease
Published in Gut Microbes, 2022
Tyler M. Cook, Virginie Mansuy-Aubert
Neuronal transmission allows for nearly instantaneous processing of sensory input or generation of motor output. This rapid signaling of peripheral neurons in the gut is critical for homeostatic mechanisms such as GI motility, secretion, and even immune response modulation.39 The peripheral nervous system (PNS) consists of vagal and spinal sensory (afferent) neurons, autonomic motor (efferent) neurons, and enteric neurons (Figure 2). Afferent neurons send information from the periphery to the brain or spinal cord, while efferent neurons project out from the central nervous system (CNS) to peripheral organs. Classifying by anatomical distribution, the twelve cranial nerves project from the brain/brainstem and spinal nerves from the spinal cord. The autonomic system is divided into sympathetic, parasympathetic, and enteric nervous systems (ENS).
The Changing Global Epidemic of HIV and Ocular Disease
Published in Ocular Immunology and Inflammation, 2020
Remco P. H. Peters, Philippe G. Kestelyn, Manfred Zierhut, John H. Kempen
Neuro-ophthalmic conditions affect the afferent neurons and/or extraocular pathways resulting in visual loss, visual field defects, and extraocular motility disorders. A study from the Democratic Republic of Congo, in the pre-HAART era, reported a very high prevalence of 60% prevalence of neuro-ophthalmic abnormalities in persons with AIDS, with eye movement disorders (51%), visual field defects (51%), optic neuropathy (31%), and ocular motor nerve palsies (26%) as most prominent manifestations.77 Studies from the USA and India found a lower frequency of neuro-ophthalmic abnormalities among persons with AIDS (10/127 and 12/100, respectively); ocular motor nerve palsies, papilledema, and optic neuritis were the most common conditions and could be attributed in most cases to opportunistic infections such as toxoplasmosis, cryptococcal meningitis, systemic CMV, and HSV encephalitis.78,79 Anecdotally, this burden has reduced dramatically now with the introduction of HAART, as might be expected with lower HIV load in blood as a result of effective therapy, but exact estimates are unavailable.