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Neurophysiology of the Developing Taste System
Published in Robert H. Cagan, Neural Mechanisms in Taste, 2020
Robert M. Bradley, Charlotte M. Mistretta
The mechanisms underlying these dramatic developmental changes are as yet unknown. It has been suggested that, during development, taste receptor membranes mature to become NaCl sensitive. Similar changes could take place during the normal turnover of taste bud cells, with newly formed taste cells being sensitive to NH4Cl and becoming more sensitive to NaCl as the cells pass through their life cycle. The mechanisms underlying the development of small receptive fields seem to involve rearrangement of the peripheral nerve fibers. Thus, a variety of mechanisms are involved in the development of the peripheral gustatory system.
Adaptations of the Physical Environment to Compensate for Sensory Changes
Published in Margaret A. Christenson, Ellen D. Taira, Aging in the Designed Environment, 2014
Margaret A. Christenson, Ellen D. Taira
The sense of taste consists of four components-sweet, salty, bitter, and sour–all of which are chemically induced. Schiffman (1975) suggests a decline in sensitivity with age for each of these gustatory qualities, although certain studies indicate an increased response to bitterness. Furthermore, some research suggests more of a decline in salty sensitivity in males (Corso, 1971). Medications, dentures and certain diseases also have an impact on the sense of taste. However, it appears that changes in the gustatory system do not seriously affect the sense of taste until relatively late in life.
ENTRIES A–Z
Published in Philip Winn, Dictionary of Biological Psychology, 2003
Tuning is a term derived from music, in which the verb to tune refers to an accurate adjustment of PITCH. It is used more generally in all of the sensory systems to describe the degree to which a NEURON responds to a particular stimulus. In the gustatory system for example (see GUSTATION), neurons in the BRAINSTEM are responsive to any taste stimulus applied to the tongue. At cortical levels neurons are present that respond maximally to particular stimuli (one of the PRIMARY TASTES): these neurons can be said to be highly and selectively tuned.
Inter-organ regulation by the brain in Drosophila development and physiology
Published in Journal of Neurogenetics, 2023
Sunggyu Yoon, Mingyu Shin, Jiwon Shim
Along with olfactory sensation, animals taste nutrients or chemicals in aqueous or solid phases through the gustatory system. Larval external sensory organs at three sites—the dorsal (DO), terminal (TO), and ventral organs (VO)—house gustatory neurons in addition to olfactory neurons in the DO and express several sensilla where sensory neurons directly innervate (Python & Stocker, 2002; Tissot et al., 1997). In adults, flies express gustatory sensory neurons in sensory organs as well as in multiple non-sensory organs, such as the legs, wings, or genitalia, with a higher expression diversity than in larval stages (Amrein & Thorne, 2005). Three gustatory receptor (GR) gene family functions to detect sweet tastes, bitter tastes, or pheromones: 8 GRs (GR5a, GR61a-f, and GR64f) sense sweetness, and 33 GRs, including GR33a, GR66a, and GR93a, detect bitter chemicals (Dahanukar et al., 2007; Fujii et al., 2015; Jiao et al., 2007, 2008; Slone et al., 2007; Weiss et al., 2011). In addition to conventional GRs, ionotropic receptors distinguish amino acids, water, or salt, thus multiplying the variety of perceived chemical sensations (Cameron et al., 2010; Ganguly et al., 2017; Zhang et al., 2013). The gustatory sensation is the primary method by which Drosophila distinguish food contents; however, a decision-making process in feeding behaviors involves combinatorial inputs from other organs, including the intestine or fat body.
Dietary experience with glucose and fructose fosters heightened avidity for glucose-containing sugars independent of TRPM5 taste transduction in mice
Published in Nutritional Neuroscience, 2023
Verenice Ascencio Gutierrez, Aracely Simental Ramos, Shushanna Khayoyan, Lindsey A. Schier
The capacity to locate, ingest, and efficiently assimilate glucose is key to health and survival for many organisms. In humans, rodents, and most other mammals, this process begins with specialized chemosensors in the gustatory system that permit the rapid detection of carbohydrates and guide adaptive responding. Humans and rodents can perceive two major dietary carbohydrate classes, maltodextrins (long chains of glucose) and simple sugars [1–9]. The heterodimeric G-protein coupled taste receptor – T1R2+T1R3 – is considered the main conduit for oral sugar sensing. It binds all the simple sugars, including the glucose molecule, low-calorie sweeteners, and some D-amino acids. Its consequent cascade of neural events ultimately gives rise to the quintessential palatable sensation humans refer to as ‘sweet.' Without the T1R2 and/or T1R3, mice retain a strong attraction to maltodextrins, but are considerably less motivated to ingest sugars and other sweeteners [10–18]. However, interestingly, loss of sweet reception does not render mice completely aguesic to sugar and rodents are capable of rapidly discriminating among certain sugars [11,13,19–28]. Collectively, these findings suggest that there may be even more oral carbohydrate sensory mechanisms left to uncover.
Olfactory dysfunction in patients after recovering from COVID-19
Published in Acta Oto-Laryngologica, 2020
Martin Sylvester Otte, Hans Nikolaus Caspar Eckel, Leonard Poluschkin, Jens Peter Klussmann, Jan Christoffer Luers
The affection of the gustatory system by SARS-CoV-2 is subject of a controversial discussion. In the current scientific discussion, a differentiation between taste and gustatory disorders, i.e. a differentiation of the retronasal aroma taste via the olfactory system from the dysfunction of the taste buds and the continuing cranial nerves is only rarely made. Although this study concentrates on the olfactory system, the performed taste screening analysing the basic qualities ‘sweet’, ‘sour’, ‘salty’ and ‘bitter’ provides indications of an additional infestation of the gustatory system by the virus. Patients with hyposmia showed significantly reduced values of the taste score compared to normosmic subjects, which speaks in favour of a higher neuroinvasive potential in these patients. Further studies with detailed psychophysical or electrophysiological measurements of gustatory functions are necessary. In these, also other gustatory test procedures should be evaluated, like electrogustometry, taste strips or filter paper disks.