Because of their ease of use, adeno-associated viruses (AAVs) are indispensable tools for much of neuroscience. Yet AAVs have been used relatively little to study the identities and connectivity of peripheral sensory neurons, principally because methods to selectively target peripheral neurons have been limited. The introduction of the AAV-PHP.
View Article and Find Full Text PDFIn mammalian taste buds, Type I cells comprise half of all cells. These are termed "glial-like" based on morphologic and molecular features, but there are limited studies describing their function. We tested whether Type I cells sense chemosensory activation of adjacent chemosensory (i.
View Article and Find Full Text PDFIn the peripheral neurons and circuits for hearing, balance, touch and pain, GABA plays diverse and important roles. In some cases, GABA is an essential player in the maintenance of sensory receptors and afferent neurons. In other instances, GABA modulates the sensory signal before it reaches CNS neurons.
View Article and Find Full Text PDFIn November 2019, the NIH held the "Sensory Nutrition and Disease" workshop to challenge multidisciplinary researchers working at the interface of sensory science, food science, psychology, neuroscience, nutrition, and health sciences to explore how chemosensation influences dietary choice and health. This report summarizes deliberations of the workshop, as well as follow-up discussion in the wake of the current pandemic. Three topics were addressed: A) the need to optimize human chemosensory testing and assessment, B) the plasticity of chemosensory systems, and C) the interplay of chemosensory signals, cognitive signals, dietary intake, and metabolism.
View Article and Find Full Text PDFNeuronal subtypes show diverse injury responses, but the molecular underpinnings remain elusive. Using transgenic mice that allow reliable visualization of axonal fate, we demonstrate that intrinsically photosensitive retinal ganglion cells (ipRGCs) are both resilient to cell death and highly regenerative. Using RNA sequencing (RNA-seq), we show genes that are differentially expressed in ipRGCs and that associate with their survival and axon regeneration.
View Article and Find Full Text PDFHow taste buds detect NaCl remains poorly understood. Among other problems, applying taste-relevant concentrations of NaCl (50-500 mm) onto isolated taste buds or cells exposes them to unphysiological (hypo/hypertonic) conditions. To overcome these limitations, we used the anterior tongue of male and female mice to implement a slice preparation in which fungiform taste buds are in a relatively intact tissue environment and stimuli are limited to the taste pore.
View Article and Find Full Text PDFStem cell-based therapies have been proposed as a strategy to replace damaged tissues, especially in the nervous system. A primary sensory modality, olfaction, is impaired in 12% of the US population, but lacks treatment options. We report here the development of a novel mouse model of inducible hyposmia and demonstrate that purified tissue-specific stem cells delivered intranasally engraft to produce olfactory neurons, achieving recovery of function.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFKey Points: Orosensory thermal trigeminal afferent neurons respond to cool, warm, and nociceptive hot temperatures with the majority activated in the cool range. Many of these thermosensitive trigeminal orosensory afferent neurons also respond to capsaicin, menthol, and/or mustard oil (allyl isothiocyanate) at concentrations found in foods and spices. There is significant but incomplete overlap between afferent trigeminal neurons that respond to oral thermal stimulation and to the above chemesthetic compounds.
View Article and Find Full Text PDFTaste buds are innervated by neurons whose cell bodies reside in cranial sensory ganglia. Studies on the functional properties and connectivity of these neurons are hindered by the lack of markers to define their molecular identities and classes. The mouse geniculate ganglion contains chemosensory neurons innervating lingual and palatal taste buds and somatosensory neurons innervating the pinna.
View Article and Find Full Text PDFThe past decade has witnessed a consolidation and refinement of the extraordinary progress made in taste research. This Review describes recent advances in our understanding of taste receptors, taste buds, and the connections between taste buds and sensory afferent fibres. The article discusses new findings regarding the cellular mechanisms for detecting tastes, new data on the transmitters involved in taste processing and new studies that address longstanding arguments about taste coding.
View Article and Find Full Text PDFOlfactory epithelium (OE) has a lifelong capacity for neurogenesis due to the presence of basal stem cells. Despite the ability to generate short-term cultures, the successful in vitro expansion of purified stem cells from adult OE has not been reported. We sought to establish expansion-competent OE stem cell cultures to facilitate further study of the mechanisms and cell populations important in OE renewal.
View Article and Find Full Text PDFGustatory stimuli are detected by taste buds and transmitted to the hindbrain via sensory afferent neurons. Whether each taste quality (sweet, bitter and so on) is encoded by separate neurons ('labelled lines') remains controversial. We used mice expressing GCaMP3 in geniculate ganglion sensory neurons to investigate taste-evoked activity.
View Article and Find Full Text PDFOlfactory tissue undergoes lifelong renewal, due to the presence of basal neural stem cells. Multiple categories of globose basal stem cells have been identified, expressing markers such as Lgr5, Ascl1, GBC-2, and c-Kit. The differentiation potential of individual globose cells has remained unclear.
View Article and Find Full Text PDFPharmacol Biochem Behav
June 2015
In rodents, saccharin consumption is suppressed when the sweet taste stimulus is paired with moderate doses of cocaine. Several hypotheses have been used to explain the seemingly contradictory effect of decreased consumption of a normally preferred substance following a highly rewarding drug. A common theme across these hypotheses is that saccharin is interpreted as less rewarding after cocaine pairing.
View Article and Find Full Text PDFOxytocin (OXT) suppresses food intake and lack of OXT leads to overconsumption of sucrose. Taste bud cells were recently discovered to express OXT-receptor. In the present study we tested whether administering OXT to wild-type mice affects their licking behavior for tastants in a paradigm designed to be sensitive to taste perception.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
January 2015
Epithelial tissues are characterized by specialized cell-cell junctions, typically localized to the apical regions of cells. These junctions are formed by interacting membrane proteins and by cytoskeletal and extracellular matrix components. Within the lingual epithelium, tight junctions join the apical tips of the gustatory sensory cells in taste buds.
View Article and Find Full Text PDFTaste buds (sensory structures embedded in oral epithelium) show a remarkable diversity of transmitters synthesized and secreted locally. The known transmitters accumulate in a cell type selective manner, with 5-HT and noradrenaline being limited to presynaptic cells, GABA being synthesized in both presynaptic and glial-like cells, and acetylcholine and ATP used for signalling by receptor cells. Each of these transmitters participates in local negative or positive feedback circuits that target particular cell types.
View Article and Find Full Text PDFThe ingestion of dietary protein is of vital importance for the maintenance of fundamental physiological processes. The taste modality umami, with its prototype stimulus, glutamate, is considered to signal the protein content of food. Umami was thought to be mediated by the heterodimeric amino acid receptor, T1R1 + T1R3.
View Article and Find Full Text PDFTaste buds are clusters of polarized sensory cells embedded in stratified oral epithelium. In adult mammals, taste buds turn over continuously and are replenished through the birth of new cells in the basal layer of the surrounding non-sensory epithelium. The half-life of cells in mammalian taste buds has been estimated as 8-12 days on average.
View Article and Find Full Text PDFMammalian taste buds use ATP as a neurotransmitter. Taste Receptor (type II) cells secrete ATP via gap junction hemichannels into the narrow extracellular spaces within a taste bud. This ATP excites primary sensory afferent fibers and also stimulates neighboring taste bud cells.
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