Biomaterial Database

Innervation of the gastrointestinal tract: patterns of aging. 2007

Robert J Phillips, and Terry L Powley

Purdue University, Department of Psychological Sciences, 703 Third Street, West Lafayette, IN 47907-2081, USA. rphillip@psych.purdue.edu

The gastrointestinal (GI) tract is innervated by intrinsic enteric neurons and by extrinsic projections, including sympathetic and parasympathetic efferents as well as visceral afferents, all of which are compromised by age to different degrees. In the present review, we summarize and illustrate key structural changes in the aging innervation of the gut, and suggest a provisional list of the general patterns of aging of the GI innervation. For example, age-related neuronal losses occur in both the myenteric plexus and submucosal plexus of the intestines. These losses start in adulthood, increase over the rest of the life span, and are specific to cholinergic neurons. Parallel losses of enteric glia also occur. The extent of neuronal and glial loss varies along an oral-to-anal gradient, with the more distal GI tract being more severely affected. Additionally, with aging, dystrophic axonal swellings and markedly dilated varicosities progressively accumulate in the sympathetic, vagal, dorsal root, and enteric nitrergic innervation of the gut. These dramatic and consistent patterns of neuropathy that characterize the aging autonomic nervous system of the GI tract are candidate mechanisms for some of the age-related declines in function evidenced in the elderly.

UI	MeSH Term	Description	Entries
D009410	Nerve Degeneration	Loss of functional activity and trophic degeneration of nerve axons and their terminal arborizations following the destruction of their cells of origin or interruption of their continuity with these cells. The pathology is characteristic of neurodegenerative diseases. Often the process of nerve degeneration is studied in research on neuroanatomical localization and correlation of the neurophysiology of neural pathways.	Neuron Degeneration,Degeneration, Nerve,Degeneration, Neuron,Degenerations, Nerve,Degenerations, Neuron,Nerve Degenerations,Neuron Degenerations
D009457	Neuroglia	The non-neuronal cells of the nervous system. They not only provide physical support, but also respond to injury, regulate the ionic and chemical composition of the extracellular milieu, participate in the BLOOD-BRAIN BARRIER and BLOOD-RETINAL BARRIER, form the myelin insulation of nervous pathways, guide neuronal migration during development, and exchange metabolites with neurons. Neuroglia have high-affinity transmitter uptake systems, voltage-dependent and transmitter-gated ion channels, and can release transmitters, but their role in signaling (as in many other functions) is unclear.	Bergmann Glia,Bergmann Glia Cells,Bergmann Glial Cells,Glia,Glia Cells,Satellite Glia,Satellite Glia Cells,Satellite Glial Cells,Glial Cells,Neuroglial Cells,Bergmann Glia Cell,Bergmann Glial Cell,Cell, Bergmann Glia,Cell, Bergmann Glial,Cell, Glia,Cell, Glial,Cell, Neuroglial,Cell, Satellite Glia,Cell, Satellite Glial,Glia Cell,Glia Cell, Bergmann,Glia Cell, Satellite,Glia, Bergmann,Glia, Satellite,Glial Cell,Glial Cell, Bergmann,Glial Cell, Satellite,Glias,Neuroglial Cell,Neuroglias,Satellite Glia Cell,Satellite Glial Cell,Satellite Glias
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000375	Aging	The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.	Senescence,Aging, Biological,Biological Aging
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001342	Autonomic Nervous System Diseases	Diseases of the AUTONOMIC NERVOUS SYSTEM, including sympathetic, parasympathetic, and enteric nervous systems.	Autonomic Disorders,Central Autonomic Nervous System Diseases,Disorders of the Autonomic Nervous System,Dysautonomia,Nervous System Diseases, Autonomic,Nervous System Diseases, Parasympathetic,Nervous System Diseases, Sympathetic,Non-Familial Dysautonomia,Parasympathetic Nervous System Diseases,Peripheral Autonomic Nervous System Diseases,Sympathetic Nervous System Diseases,ANS (Autonomic Nervous System) Diseases,ANS Diseases,Autonomic Central Nervous System Diseases,Autonomic Diseases,Autonomic Nervous System Disorders,Autonomic Peripheral Nervous System Diseases,Segmental Autonomic Dysfunction,ANS Disease,Autonomic Disease,Autonomic Disorder,Autonomic Dysfunction, Segmental,Autonomic Dysfunctions, Segmental,Disorder, Autonomic,Dysautonomia, Non-Familial,Dysautonomias,Non Familial Dysautonomia,Non-Familial Dysautonomias,Segmental Autonomic Dysfunctions
D017615	Enteric Nervous System	Two ganglionated neural plexuses in the gut wall which form one of the three major divisions of the autonomic nervous system. The enteric nervous system innervates the gastrointestinal tract, the pancreas, and the gallbladder. It contains sensory neurons, interneurons, and motor neurons. Thus the circuitry can autonomously sense the tension and the chemical environment in the gut and regulate blood vessel tone, motility, secretions, and fluid transport. The system is itself governed by the central nervous system and receives both parasympathetic and sympathetic innervation. (From Kandel, Schwartz, and Jessel, Principles of Neural Science, 3d ed, p766)	Enteric Nervous Systems,Nervous System, Enteric,Nervous Systems, Enteric,System, Enteric Nervous,Systems, Enteric Nervous
D041981	Gastrointestinal Tract	Generally refers to the digestive structures stretching from the MOUTH to ANUS, but does not include the accessory glandular organs (LIVER; BILIARY TRACT; PANCREAS).	Digestive Tract,GI Tract,Digestive Tracts,GI Tracts,Gastrointestinal Tracts
D023421	Models, Animal	Non-human animals, selected because of specific characteristics, for use in experimental research, teaching, or testing.	Experimental Animal Models,Laboratory Animal Models,Animal Model,Animal Model, Experimental,Animal Model, Laboratory,Animal Models,Animal Models, Experimental,Animal Models, Laboratory,Experimental Animal Model,Laboratory Animal Model,Model, Animal,Model, Experimental Animal,Model, Laboratory Animal,Models, Experimental Animal,Models, Laboratory Animal