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Ohla K, Yoshida R, Roper SD, Di Lorenzo PM, Victor JD, Boughter JD, Fletcher M, Katz DB, Chaudhari N. Recognizing Taste: Coding Patterns Along the Neural Axis in Mammals. Chem Senses 2019; 44:237-247. [PMID: 30788507 PMCID: PMC6462759 DOI: 10.1093/chemse/bjz013] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The gustatory system encodes information about chemical identity, nutritional value, and concentration of sensory stimuli before transmitting the signal from taste buds to central neurons that process and transform the signal. Deciphering the coding logic for taste quality requires examining responses at each level along the neural axis-from peripheral sensory organs to gustatory cortex. From the earliest single-fiber recordings, it was clear that some afferent neurons respond uniquely and others to stimuli of multiple qualities. There is frequently a "best stimulus" for a given neuron, leading to the suggestion that taste exhibits "labeled line coding." In the extreme, a strict "labeled line" requires neurons and pathways dedicated to single qualities (e.g., sweet, bitter, etc.). At the other end of the spectrum, "across-fiber," "combinatorial," or "ensemble" coding requires minimal specific information to be imparted by a single neuron. Instead, taste quality information is encoded by simultaneous activity in ensembles of afferent fibers. Further, "temporal coding" models have proposed that certain features of taste quality may be embedded in the cadence of impulse activity. Taste receptor proteins are often expressed in nonoverlapping sets of cells in taste buds apparently supporting "labeled lines." Yet, taste buds include both narrowly and broadly tuned cells. As gustatory signals proceed to the hindbrain and on to higher centers, coding becomes more distributed and temporal patterns of activity become important. Here, we present the conundrum of taste coding in the light of current electrophysiological and imaging techniques at several levels of the gustatory processing pathway.
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Affiliation(s)
- Kathrin Ohla
- Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Jülich, Germany
| | - Ryusuke Yoshida
- Section of Oral Neuroscience and OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
- Department of Oral Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama City, Japan
| | - Stephen D Roper
- Department of Physiology and Biophysics, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - Jonathan D Victor
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, USA
| | - John D Boughter
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Max Fletcher
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Donald B Katz
- Volen Center for Complex Systems, Brandeis University, Waltham, MA, USA
| | - Nirupa Chaudhari
- Department of Physiology and Biophysics, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, USA
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Stabili L, Parisi MG, Parrinello D, Cammarata M. Cnidarian Interaction with Microbial Communities: From Aid to Animal's Health to Rejection Responses. Mar Drugs 2018; 16:E296. [PMID: 30142922 PMCID: PMC6164757 DOI: 10.3390/md16090296] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 08/11/2018] [Accepted: 08/16/2018] [Indexed: 02/07/2023] Open
Abstract
The phylum Cnidaria is an ancient branch in the tree of metazoans. Several species exert a remarkable longevity, suggesting the existence of a developed and consistent defense mechanism of the innate immunity capable to overcome the potential repeated exposure to microbial pathogenic agents. Increasing evidence indicates that the innate immune system in Cnidarians is not only involved in the disruption of harmful microorganisms, but also is crucial in structuring tissue-associated microbial communities that are essential components of the Cnidarian holobiont and useful to the animal's health for several functions, including metabolism, immune defense, development, and behavior. Sometimes, the shifts in the normal microbiota may be used as "early" bio-indicators of both environmental changes and/or animal disease. Here the Cnidarians relationships with microbial communities and the potential biotechnological applications are summarized and discussed.
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Affiliation(s)
- Loredana Stabili
- Istituto per l'Ambiente Marino Costiero, U.O.S. di Taranto, CNR, Via Roma 3, 74123 Taranto, Italy.
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, via Prov.le Lecce Monteroni, 73100 Lecce, Italy.
| | - Maria Giovanna Parisi
- Laboratory of Marine Immunobiology, Dipartimento delle Scienze della Terra e del Mare, Università di Palermo, Viale delle Scienze Ed. 16, 90128 Palermo, Italy.
| | - Daniela Parrinello
- Laboratory of Marine Immunobiology, Dipartimento delle Scienze della Terra e del Mare, Università di Palermo, Viale delle Scienze Ed. 16, 90128 Palermo, Italy.
| | - Matteo Cammarata
- Laboratory of Marine Immunobiology, Dipartimento delle Scienze della Terra e del Mare, Università di Palermo, Viale delle Scienze Ed. 16, 90128 Palermo, Italy.
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Hochberg R, Wallace RL, Walsh EJ. Soft Bodies, Hard Jaws: An Introduction to the Symposium, with Rotifers as Models of Jaw Diversity. Integr Comp Biol 2015; 55:179-92. [PMID: 25796591 PMCID: PMC6296403 DOI: 10.1093/icb/icv002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Jaws have evolved numerous times in the animal kingdom and they display a wide variety of structural, compositional, and functional characteristics that reflect their polyphyletic origins. Among soft-bodied invertebrates, jaws are known from annelids, chaetognaths, flatworms, gnathostomulids, micrognathozoans, mollusks, rotifers, and several ecdysozoans. Depending on the taxon, jaws may function in the capture of prey (e.g., chaetognaths and flatworms), processing of prey (e.g., gnathostomulids and onychophorans), or both (e.g., rotifers). Although structural diversity among invertebrates’ jaws is becoming better characterized with the use of electron microscopy, many details remain poorly described, including neuromuscular control, elemental composition, and physical characteristics, such as hardness and resistance to wear. Unfortunately, absence of relevant data has impeded understanding of their functional diversity and evolutionary origins. With this symposium, we bring together researchers of disparately jawed taxa to draw structural and mechanistic comparisons among species to determine their commonalities. Additionally, we show that rotifers’ jaws, which are perhaps the best-characterized jaws among invertebrates, are still enigmatic with regard to their origins and mechanics. Nevertheless, technologies such as energy dispersive X-ray spectroscopy (EDX) and 3D modeling are being used to characterize their chemical composition and to develop physical models that allow exploration of their mechanical properties, respectively. We predict that these methods can also be used to develop biomimetic and bioinspired constructs based on the full range of the complexity of jaws, and that such constructs also can be developed from other invertebrate taxa. These approaches may also shed light on common developmental and physiological processes that facilitate the evolution of invertebrates’ jaws.
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Affiliation(s)
- Rick Hochberg
- *Department of Biology, University of Massachusetts Lowell, One University Avenue, Lowell, MA 01854, USA
| | - Robert L. Wallace
- Biology Department, Ripon College, 300 Seward Street, Ripon, WI 54971, USA
| | - Elizabeth J. Walsh
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX 79968, USA
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Hellekant G, Schmolling J, Marambaud P, Rose-Hellekant TA. CALHM1 Deletion in Mice Affects Glossopharyngeal Taste Responses, Food Intake, Body Weight, and Life Span. Chem Senses 2015; 40:373-9. [PMID: 25855639 DOI: 10.1093/chemse/bjv009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Stimulation of Type II taste receptor cells (TRCs) with T1R taste receptors causes sweet or umami taste, whereas T2Rs elicit bitter taste. Type II TRCs contain the calcium channel, calcium homeostasis modulator protein 1 (CALHM1), which releases adenosine triphosphate (ATP) transmitter to taste fibers. We have previously demonstrated with chorda tympani nerve recordings and two-bottle preference (TBP) tests that mice with genetically deleted Calhm1 (knockout [KO]) have severely impaired perception of sweet, bitter, and umami compounds, whereas their sour and salty tasting ability is unaltered. Here, we present data from KO mice of effects on glossopharyngeal (NG) nerve responses, TBP, food intake, body weight, and life span. KO mice have no NG response to sweet and a suppressed response to bitter compared with control (wild-type [WT]) mice. KO mice showed some NG response to umami, suggesting that umami taste involves both CALHM1- and non-CALHM1-modulated signals. NG responses to sour and salty were not significantly different between KO and WT mice. Behavioral data conformed in general with the NG data. Adult KO mice consumed less food, weighed significantly less, and lived almost a year longer than WT mice. Taken together, these data demonstrate that sweet taste majorly influences food intake, body weight, and life span.
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Affiliation(s)
- Göran Hellekant
- Department of Biomedical Sciences, Medical School, University of Minnesota, Duluth, MN 55812, USA and
| | - Jared Schmolling
- Department of Biomedical Sciences, Medical School, University of Minnesota, Duluth, MN 55812, USA and
| | - Philippe Marambaud
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, The Feinstein Institute for Medical Research, Manhasset, NY 11030, USA
| | - Teresa A Rose-Hellekant
- Department of Biomedical Sciences, Medical School, University of Minnesota, Duluth, MN 55812, USA and
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Hellekant G, Roberts T, Elmer D, Cragin T, Danilova V. Responses of single chorda tympani taste fibers of the calf (Bos taurus). Chem Senses 2010; 35:383-94. [PMID: 20212013 DOI: 10.1093/chemse/bjq026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In spite of a wealth of information on feed and nutrition in cattle, there little is published of what they actually can taste. Here, we attempt to remedy some of this deficiency by presenting recordings of the chorda tympani proper nerve of young Holstein calves during stimulation of approximately 30 compounds. Hierarchical cluster analysis of 46 single taste fibers separated 4 fiber clusters: N (salt best), H (sour best), and 2 clusters, which could not be related to any human taste quality. The N fibers responded best to LiCl, NaCl, urea, monosodium glutamate, and KCl, whereas the H fibers responded strongly to citric and ascorbic acid. Interestingly, propionic and butyric acid stimulated best the 3rd cluster, whereas the 4th cluster responded best to denatonium benzoate and only to a small extent to quinine hydrochloride. Sweeteners stimulated moderately all clusters. Beginning with the largest response to sweet, the order between the responses was: acesulfame-K, saccharin, D-phenylalanine, glycine, sucrose, fructose, erythritol, cyclamate, and lactose. Alitame, aspartame, and super-aspartame evoked no or little responses. Three and 5 M ethanol stimulated all clusters. Comparison with taste fibers in other species suggests that the taste world of cattle is quite different from other species'.
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Affiliation(s)
- Göran Hellekant
- Department of Physiology and Pharmacology, University of Minnesota Duluth, 1035 University Drive, Duluth, MN 55811, USA.
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Maillet EL, Margolskee RF, Mosinger B. Phenoxy herbicides and fibrates potently inhibit the human chemosensory receptor subunit T1R3. J Med Chem 2009; 52:6931-5. [PMID: 19817384 DOI: 10.1021/jm900823s] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We show that phenoxyauxin herbicides and lipid-lowering fibrates inhibit human but not rodent T1R3. T1R3 as a coreceptor in taste cells responds to sweet compounds and amino acids; in endocrine cells of gut and pancreas T1R3 contributes to glucose sensing. Thus, certain effects of fibrates in treating hyperlipidemia and type II diabetes may be via actions on T1R3. Likewise, phenoxy herbicides may have adverse metabolic effects in humans that would have gone undetected in studies on rodents.
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Affiliation(s)
- Emeline L Maillet
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029, USA
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