Drugs Affecting Autonomic Ganglia (Including the Adrenal Medulla)
Kenneth J. Broadley in Autonomic Pharmacology, 2017
Autonomic ganglia consist of clusters of postganglionic cell bodies which, in the case of the sympathetic division of the autonomic nervous system, are located alongside the vertebral column as the sympathetic chain (vertebral ganglia) or more distally in the body cavities as discrete peripheral ganglia. The parasympathetic ganglia are located usually within the organ that is innervated. They form more diffuse networks or plexuses of cells, such as the myenteric plexus of the gastrointestinal tract (Figure 1.5). The anatomical differences between parasympathetic and sympathetic ganglia are described in Chapter 1 and are illustrated in Figure 1.3 and 1.4. The sympathetic ganglia form more discrete structures and are therefore more accessible for study, since electrodes may be placed pre- and postganglionically to examine the pharmacological effects of drugs upon transmission through the ganglion and upon the end organ response to nerve stimulation.
Inhaled therapeutics in chronic obstructive pulmonary disease
Anthony J. Hickey, Heidi M. Mansour in Inhalation Aerosols, 2019
Smooth muscle tone of the respiratory tract is largely determined by the activity of the parasympathetic nervous system, with acetylcholine acting as the mediator on muscarinic receptors in the large airways. There are five G protein–coupled muscarinic receptors (M1-M5), but only the first three are found in the airways and are of pharmacologic significance (11). Muscarinic receptor density is greatest in the larger airways and diminishes peripherally (12). The M1 receptor is found in parasympathetic ganglia, and activation facilitates neurotransmission of acetylcholine and consequent bronchoconstriction. The M2 receptor is located on postganglionic nerve terminals; it functions as an auto-receptor and inhibits further release of acetylcholine. Activation of M2 receptors also leads to a reduction in beta-2 receptor signaling and causes a subsequent reduction in airway smooth muscle relaxation. The M3 receptor is the major receptor on submucosal glands and airway vascular endothelium; activation leads to a series of intracellular reactions that eventually causes smooth muscle constriction and increased mucus secretion (12). Given the properties of these receptor subtypes, the optimally constructed anticholinergic agent for COPD patients should antagonize M1 and M3 with minimal affinity for M2 (13).
Structure and Function of the Lower Urinary Tract
Anthony R. Mundy, John M. Fitzpatrick, David E. Neal, Nicholas J. R. George in The Scientific Basis of Urology, 2010
The acetylcholine released from the varicosities at the ends of parasympathetic nerves has a variety of different actions depending on exactly where it is released and particularly on the nature of the receptors present. As a general rule, the same applies to all transmitters and all nerves. Many transmitters are associated with several different types of receptors and each type of receptor has several subtypes, each with different effects. When acetylcholine is released from preganglionic nerve fibers in the parasympathetic ganglia of the pelvic plexus and in the bladder wall its principal targets are the receptors on the cell bodies of the postganglionic nerves. These receptors are nicotinic in type, which are ligand-gated ion channels.
Metastatic brain carotid body paraganglioma with endocrine activity: a case report and literature review
Published in British Journal of Neurosurgery, 2019
Xiang Wang, Xianglan Zhu, Jinxiu Chen, Yanhui Liu, Qing Mao
Paraganglioma is a chromaffin-cell tumor located at extra-adrenal sites along the sympathetic and/or the parasympathetic chain. Carotid body tumor, which is one of the parasympathetic paragangliomas, also named chemodectomas, originates from similar cells that have parasympathetic innervations and chemoreceptor function. Most of the paragangliomas are benign; however, malignant tumors with aggressive behavior and distant metastasis can also occur. The most common metastatic sites for paraganglioma are local lymph nodes, bone, liver, and lung.1 A review of the literature showed that there were only six reports on paraganglioma with intracranial metastases. Two of these cases were calvarial metastasis, and the other four cases were accompanied with multiple intracerebral metastasis.1–3 The tumor may originate from any location where parasympathetic ganglia can be found. Moreover, adrenal and retroperitoneal paragangliomas have a high incidence for distant metastasis as reported in the literature.2 However, the carotid body as a primary tumor site for an intracranial metastasis has not yet been reported. In this case, the patient had undergone left carotid body tumor resection 2 years ago, and at that time, the tumor was located in the left parietal lobe, which is a common location of intracerebral metastases. To the best of our knowledge, the present case is the first report of intracerebral metastases from carotid body paraganglioma.
Indacaterol/glycopyrronium/mometasone fixed dose combination for uncontrolled asthma
Published in Expert Review of Respiratory Medicine, 2022
Corrado Pelaia, Claudia Crimi, Nunzio Crimi, Luisa Ricciardi, Nicola Scichilone, Giuseppe Valenti, Ornella Bonavita, Stefano Andaloro, Paolo Morini, Andrea Rizzi, Girolamo Pelaia
Anticholinergic bronchodilators antagonize the parasympathetic system by acting on the acetylcholine receptors expressed on airway smooth muscles and lung parasympathetic nerves. There are two groups of acetylcholine receptors: nicotinic- and muscarinic- and the muscarinic subtypes M1, M2 and M3 are primarily involved in the regulation of bronchoconstriction. All muscarinic receptor subtypes are widely expressed in different tissues (smooth muscles, brain, heart and the sinoatrial node, gastrointestinal tract, pupils, blood vessels and the parasympathetic nervous system). Muscarinic M2 receptors in the heart regulate heart beating by reducing the activation of the sinus node, while the M3 subtypes are responsible of contraction of the muscles of gastrointestinal tract, or blood vessel vasodilation [32,33]. Specifically referring to airway tract activity, M1 receptors are widely distributed in all parasympathetic ganglia and they act by regulating cholinergic transmission. M2 receptors are found in the pre-junctional membranes of the neuromuscular junctions of airway smooth muscles and reduce acetylcholine transmission through a negative feedback. M3 receptors are mainly expressed in smooth muscle cells in the lungs, regulating muscle contraction, while within the submucosal glands of the lung, M3 receptors regulate mucus secretion. Thus, it is preferable that antimuscarinic bronchodilators present higher affinity for M1 and M3 receptors, and lower affinity for M2 receptors [34].
New perspectives on the role of muscarinic antagonists in asthma therapy
Published in Expert Review of Respiratory Medicine, 2020
Maria Gabriella Matera, Carmela Belardo, Michele Rinaldi, Barbara Rinaldi, Mario Cazzola
In the airways, plasticity occurs with changes in connections between neurons and with changes in neurons themselves [16]. It has been suggested that the mechanisms that contribute to neuronal plasticity in asthma could be driven by immune cells/inflammation, such as eosinophils and mast cells, or by cells that induce and promote nerve growth and impaired function, such as neurotrophins [16]. Neurotrophins, mainly nerve growth factor, that is a fundamental protagonist in neuronal aspects of asthma, and brain-derived neurotrophic factor, are released from different cell types in the airways, including neurons, epithelium, airway smooth muscle, lymphocytes, macrophages, and mast cells, and their expression increases in asthma [16]. Plasticity in asthma manifests itself with an increase in the density of the parasympathetic ganglia (the so-called chronic neuronal remodeling) with consequent increase in the release of acetylcholine and an enhancement in cholinergic tone. The resulting neuronal remodeling causes further density of the cholinergic nerves [16]. It is now evident that apart from inflammation, there is also a role for the nervous system in controlling airway structure and function, and, thus, in influencing asthma symptoms and airway hyperreactivity [17].
Related Knowledge Centers
- Autonomic Ganglion
- Ciliary Ganglion
- Ciliary Muscle
- Iris Sphincter Muscle
- Lacrimal Gland
- Pterygopalatine Ganglion
- Submandibular Gland
- Nasal Cavity
- Parasympathetic Nervous System
- Submandibular Ganglion