Taste receptor cells detect chemicals in the oral cavity and transmit this information to taste nerves, but neurotransmitter(s) have not been identified. We report that adenosine 5'-triphosphate (ATP) is key neurotransmitter system. Genetic elimination of ionotropic purinergic receptors (P2X2 P2X3) eliminates responses although nerves remain responsive touch, temperature, menthol. Similarly, P2X-knockout mice show greatly reduced behavioral sweeteners, glutamate, bitter substances. Finally,...

Inhalation of irritating substances leads to activation the trigeminal nerve, triggering protective reflexes that include apnea or sneezing. Receptors for irritants are generally assumed be located exclusively on free nerve endings within nasal epithelium, requiring diffuse through junctional barrier at epithelial surface activate receptors. We find, in both rats and mice, an extensive population chemosensory cells reach epithelium form synaptic contacts with afferent fibers. These express...

The upper respiratory tract is continually assaulted with harmful dusts and xenobiotics carried on the incoming airstream. Detection of such irritants by trigeminal nerve evokes protective reflexes, including sneezing, apnea, local neurogenic inflammation mucosa. Although free intra-epithelial endings can detect certain lipophilic (e.g., mints, ammonia), epithelium also houses a population trigeminally innervated solitary chemosensory cells (SCCs) that express T2R bitter taste receptors...

Significance Millions of people worldwide suffer from chronic nasal inflammation involving obstructed airflow and discharge. Although is often considered to be a reaction allergens, approximately one-quarter all cases are nonallergic rhinitis. The causes this disease unknown, but symptoms may triggered or exacerbated by variety inhaled irritants even seemingly innocuous odors. We report here that specialized chemosensory cells the epithelium mice detect potential transmit information...

The olfactory epithelium of fish contains three intermingled types receptor neurons (ORNs): ciliated, microvillous, and crypt. present experiments were undertaken to test whether the different ORNs respond classes odorants via families molecules G-proteins corresponding morphology ORN. In catfish, ciliated express OR-type receptors Galpha(olf). Microvillous are heterogeneous, with many expressing Galpha(q)/11, whereas crypt Galpha(o). Retrograde tracing show that project predominantly...

Abstract Taste buds contain a variety of morphological and histochemical types elongate cells. Serotonin, neuron‐specific enolase (NSE), ubiquitin carboxyl terminal hydrolase (PGP 9.5), neural cell adhesion molecule (N‐CAM) all have been described as being present in the morphologically defined Type III taste cells rats. In order to determine whether these substances coexist single cell, we undertook immunohistochemical ultrastructural analysis Double‐label studies show that PGP 9.5 NSE...

Abstract The presence of one or more calcium‐dependent ecto‐ATPases (enzymes that hydrolyze extracellular 5′‐triphosphates) in mammalian taste buds was first shown histochemically. Recent studies have established dominant consist enzymes now called nucleoside triphosphate diphosphohydrolases (NTPDases). Massively parallel signature sequencing (MPSS) from murine epithelium provided molecular evidence suggesting NTPDase2 is the most likely member present mouse papillae. Immunocytochemical and...

Abstract A number of recent experiments suggest that grafted dopaminergic neurons provide functional input to a host caudoputamen which previously had been deprived its input. The purpose the present study was determine whether tyrosine hydroxylase immunoreactive processes originate in graft participate morphologically identifiable synapses neuropil. Prior transplantation, adult Sprague‐Dawley rats received unilateral injections 6‐hydroxydopamine into medial forebrain bundle. Animals were...

Abstract The nasal epithelium is richly invested with peptidergic (substance P and calcitonin gene‐related peptide [CGRP]) trigeminal polymodal nociceptors, which respond to numerous odorants as well irritants. Peptidergic sensory fibers also enter the glomerular layer of olfactory bulb. To test whether in bulb are collaterals epithelial fibers, we utilized dual retrograde labeling techniques rats identify ganglion cells innervating each these territories. Nuclear Yellow was injected into...

Chemical irritation of airway mucosa elicits a variety reflex responses such as coughing, apnea, and laryngeal closure. Inhaled irritants can activate either chemosensitive free nerve endings, taste buds or solitary chemosensory cells (SCCs). The SCC population lies in the nasal respiratory epithelium, vomeronasal organ, larynx, well deeper airway. objective this study is to map distribution SCCs within airways determine elements transduction cascade expressed these SCCs.We utilized...

Abstract The olfactory system of many terrestrial vertebrates comprises a main organ and vomeronasal each containing morphologically distinct type receptor neuron (ORN). two cell types also differ in the expression G‐proteins odorant molecules. Fish do not have organ, their neurons—three different morphological types—are contained one epithelium. goldfish appears as rosette, with sensory epithelium lying along proximal portion lamella, where it attaches to midline raphe. Using...

The transient receptor potential channel, PKD2L1, is reported to be a candidate for sour taste based on molecular biological and functional studies. Here, we investigated the expression pattern of PKD2L1-immunoreactivity (IR) in buds mouse. PKD2L1-IR present few elongate cells each bud as previously. PKD2L1-expressing are different from those expressing PLCbeta2, marker Type II cells. Likewise PKD2L1-immunoreactive do not express ecto-ATPase which marks I PKD2L1-positive immunoreactive...

Abstract Using degeneration staining methods, central projections of the olfactory tracts in bullhead catfish, Ictalurus nebulosus were studied. Separate lesions made lateral and medial an attempt to separate their zones projection. Three major terminal fields found: lateral, central‐posterior complex. Two additional minor seen: interbulbar hypothalamic. The division tract terminates hypothalamic fields. projects medial, posterior All found bilaterally; partly crossing both anterior...

Taste is a discriminative sense involving specialized receptor cells of the oral cavity (taste buds) and at least two distinct families G protein-coupled molecules that detect nutritionally important substances or potential toxins. Yet mechanisms drive taste also are utilized by numerous systems throughout body. How why these so-called receptors used to regulate digestion respiration now matter intense study. In this article we provide historical perspective an overview systems, leading...

<ns4:p>In the last few years, single-cell profiling of taste cells and ganglion has advanced our understanding transduction, encoding, transmission information from buds as relayed to central nervous system. This review focuses on new knowledge these molecular approaches attempts place this in context previous questions findings field. The individual within a bud are molecularly specialized for detection one primary qualities: salt, sour, sweet, umami, bitter. Transduction transmitter...

Amiloride-sensitive Na+ channels play an important role in transducing salt taste. Previous studies revealed that rodent taste cells, the channel shares electrophysiological and pharmacological properties with epithelial channel, ENaC. Using subunit-specific antibodies directed against α, β, γ subunits of rat ENaC (rENaC), we observed cytoplasmic immunoreactivity for all three nearly cells fungiform papillae, about half foliate vallate papillae. The intensity labeling papillae was...

BACKGROUND Dyspepsia and irritable bowel syndrome are suitable conditions for assessment of quality life. Their similarities justify the elaboration a single specific questionnaire two conditions. AIMS To examine process leading to validation psychometric properties functional digestive disorders life (FDDQL). METHODS Initially, was given 154 patients, assess its acceptability reproducibility, analyse content, reduce number items. Its responsiveness tested during therapeutic trials which...

Except for taste bud cells, all sensory receptor cells and neurons have been shown to originate from neurogenic ectoderm (i.e., neural tube, crest, or ectodermal placodes). Descriptive studies on buds indicate that they, however, may arise local epithelium. To determine whether epithelium, the tongues of X chromosome-inactivation mosaic mice were examined. Results this analysis show their surrounding epithelium always match in terms marker. This suggests epithelial a common progenitor tissue...

The olfactory epithelium of teleost fishes contains ciliated and microvillous receptor neurons intermingled with supporting cells. Recently the crypt cell, a third type neuron (ORN), was described for two ostariophysans. This ORN bears apical microvilli as well occult cilia extending into at apex cell. present study used scanning transmission electron-microscopic methods to examine how widespread this cell is in other groups fish. We investigated epithelia 18 species, freshwater marine,...

Inhaled airborne irritants elicit sensory responses in trigeminal nerves innervating the nasal epithelium, leading to protective reflexes. The mechanisms involved detection of odorous are poorly understood. We identified a large population solitary chemosensory cells expressing transient receptor potential channel M5 (TRPM5) using transgenic mice where promoter TRPM5 drives expression green fluorescent protein (GFP). Most these lie anterior cavity. These GFP-labeled exhibited...

Abstract The second order projections of the gustatory system in catfish were examined using both retrograde (HRP) and anterograde (degeneration autoradiographic) hodological methods. Golgi‐stained material was used to demonstrate different cell types primary sensory area, facial lobe. Efferents from lobe gather into ascending tract terminates largely medial funicular nucleus commissural Cajal region obex. A small portion descending continues caudally terminate dorsal horn spinal cord....

Abstract The respiratory and olfactory mucosae of rats mice were examined at ultrastructural levels for the presence intraepithelial nerve endings. Immunocytochemical studies utilizing antisera directed against substance P calcitonin gene‐related peptide (CGRP) revealed numerous peptide‐immunoreactive fibers near basal region epithelium. Occasional transepithelial observed to extend outward nearly reach epithelial surface. In no cases, however, did surface, but instead, stopped line tight...