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Developmental Cell Mar 2003Major histocompatibility complex class Ib molecules may play a surprising role in pheromone detection in mammals. (Review)
Review
Major histocompatibility complex class Ib molecules may play a surprising role in pheromone detection in mammals.
Topics: Animals; Cell Membrane; Chemoreceptor Cells; Gene Expression Regulation; Histocompatibility Antigens Class I; Humans; Sex Attractants; Sexual Behavior, Animal; Vomeronasal Organ
PubMed: 12636910
DOI: 10.1016/s1534-5807(03)00066-2 -
Physiology (Bethesda, Md.) Jul 2019The carotid body has emerged as a therapeutic target for cardio-respiratory-metabolic diseases. With the expansive functions of the chemoreflex, we sought mechanisms to... (Review)
Review
The carotid body has emerged as a therapeutic target for cardio-respiratory-metabolic diseases. With the expansive functions of the chemoreflex, we sought mechanisms to explain differential control of individual responses. We purport a remarkable correlation between phenotype of a chemosensory unit (glomus cell-sensory afferent) with a distinct component of the reflex response. This logic could permit differential modulation of distinct chemoreflex responses, a strategy ideal for therapeutic exploitation.
Topics: Animals; Brain; Carotid Body; Chemoreceptor Cells; Humans; Logic; Reflex
PubMed: 31165684
DOI: 10.1152/physiol.00057.2018 -
Molecules and Cells Mar 2013Alarm pheromones are important semiochemicals used by many animal species to alert conspecifics or other related species of impending danger. In this review, we describe... (Review)
Review
Alarm pheromones are important semiochemicals used by many animal species to alert conspecifics or other related species of impending danger. In this review, we describe recent developments in our understanding of the neural mechanisms underlying the ability of fruit flies, zebrafish and mice to mediate the detection of alarm pheromones. Specifically, alarm pheromones are detected in these species through specialized olfactory subsystems that are unique to the chemosensitive receptors, second messenger-signaling and physiology. Thus, the alarm pheromones appears to be detected by signaling mechanisms that are distinct from those seen in the canonical olfactory system.
Topics: Animal Communication; Animals; Chemoreceptor Cells; Olfactory Perception; Pheromones; Second Messenger Systems; Smell; Ultrasonography
PubMed: 23471444
DOI: 10.1007/s10059-013-0056-3 -
Respiratory Physiology & Neurobiology Oct 2010The rat retrotrapezoid nucleus (RTN) contains about 2000 Phox2b-expressing glutamatergic neurons (ccRTN neurons; 800 in mice) with a well-understood developmental... (Review)
Review
The rat retrotrapezoid nucleus (RTN) contains about 2000 Phox2b-expressing glutamatergic neurons (ccRTN neurons; 800 in mice) with a well-understood developmental lineage. ccRTN neuron development fails in mice carrying a Phox2b mutation commonly present in the congenital central hypoventilation syndrome. In adulthood, ccRTN neurons regulate the breathing rate and intensity, and may regulate active expiration along with other neighboring respiratory neurons. Prenatally, ccRTN neurons form an autonomous oscillator (embryonic parafacial group, e-pF) that activates and possibly paces inspiration. The pacemaker properties of the ccRTN neurons probably vanish after birth to be replaced by synaptic drives. The neonatal parafacial respiratory group (pfRG) may represent a transitional phase during which ccRTN neurons lose their group pacemaker properties. ccRTN neurons are activated by acidification via an intrinsic mechanism or via ATP released by glia. In summary, throughout life, ccRTN neurons seem to be a critical hub for the regulation of CO(2) via breathing.
Topics: Animals; Chemoreceptor Cells; Humans; Mice; Neurons; Rats; Respiratory Center; Respiratory Physiological Phenomena
PubMed: 20188865
DOI: 10.1016/j.resp.2010.02.005 -
Nature Communications Oct 2018The bacterial chemosensory arrays are a notable model for studying the basic principles of receptor clustering and cellular organization. Here, we provide a new...
The bacterial chemosensory arrays are a notable model for studying the basic principles of receptor clustering and cellular organization. Here, we provide a new perspective regarding the long-term dynamics of these clusters in growing E. coli cells. We demonstrate that pre-existing lateral clusters tend to avoid translocation to pole regions and, therefore, continually shuttle between the cell poles for many generations while being static relative to the local cell-wall matrix. We also show that the polar preference of clusters results fundamentally from reduced clustering efficiency in the lateral region, rather than a developmental-like progression of clusters. Furthermore, polar preference is surprisingly robust to structural alterations designed to probe preference due to curvature sorting, perturbing the cell envelope physiology affects the cluster-size distribution, and the size-dependent mobility of receptor complexes differs between polar and lateral regions. Thus, distinct envelope physiology in the polar and lateral cell regions may contribute to polar preference.
Topics: Cell Membrane; Chemoreceptor Cells; Escherichia coli; Receptors, Cell Surface
PubMed: 30361683
DOI: 10.1038/s41467-018-06835-5 -
Respiratory Physiology & Neurobiology Oct 2010Much progress has been made in our understanding of central chemoreception since the seminal experiments of Fencl, Loeschcke, Mitchell and others, including... (Review)
Review
Much progress has been made in our understanding of central chemoreception since the seminal experiments of Fencl, Loeschcke, Mitchell and others, including identification of new brainstem regions and specific neuron types that may serve as central "sensors" of CO(2)/pH. In this review, we discuss key attributes, or minimal requirements a neuron/cell must possess to be defined as a central respiratory chemoreceptor, and summarize how well each of the various candidates fulfill these minimal criteria-especially the presence of intrinsic chemosensitivity. We then discuss some of the in vitro and in vivo evidence in support of the conclusion that medullary serotonin (5-HT) neurons are central chemoreceptors. We also provide an additional hypothesis that chemosensitive medullary 5-HT neurons are poised to integrate multiple synaptic inputs from various other sources thought to influence ventilation. Finally, we discuss open questions and future studies that may aid in continuing our advances in understanding central chemoreception.
Topics: Animals; Chemoreceptor Cells; Humans; Medulla Oblongata; Neurons; Respiratory Physiological Phenomena; Serotonin
PubMed: 20226279
DOI: 10.1016/j.resp.2010.03.006 -
Current Biology : CB Sep 2005The sense of taste is essential for the survival of virtually all animals. Considered a 'primitive sense' and present in the form of chemotaxis in many bacteria, taste... (Review)
Review
The sense of taste is essential for the survival of virtually all animals. Considered a 'primitive sense' and present in the form of chemotaxis in many bacteria, taste is also a sense of sophistication in humans. Regardless, taste behavior is a crucial activity for the world's most abundant (insects) and most successful (mammals) inhabitants, providing a means of discrimination between nutrient-rich substrates, such as sugars and amino acids, from harmful, mostly bitter-tasting chemicals present in many plants. In this review, we present an update on progress in understanding taste perception in the model fruit fly Drosophila melanogaster. An introduction to the fly's taste system will be presented first, followed by a description of relevant behavioral assays developed to quantify taste perception at the organismal level and a short overview of electrophysiological studies performed on taste cells. The focal point will be the recent molecular-genetic investigations of the gustatory receptor (Gr) genes, which is complemented by a comparison between Drosophila and mammalian taste perception and transduction. Finally, we provide a perspective on the future of Drosophila taste research, including three specific proposals that seem uniquely applicable to this exquisite model system and cannot, at least currently, be pursued elsewhere.
Topics: Animals; Bacterial Proteins; Behavior, Animal; Chemoreceptor Cells; Drosophila Proteins; Drosophila melanogaster; Electrophysiology; Gene Expression; Models, Biological; Multigene Family; Perception; Receptors, Cell Surface; Signal Transduction; Taste
PubMed: 16139201
DOI: 10.1016/j.cub.2005.08.021 -
Cellular and Molecular Life Sciences :... Jul 2006Our understanding of the biochemical mechanisms that mediate chemoreception in insects has been greatly improved after the discovery of olfactory and taste receptor... (Comparative Study)
Comparative Study Review
Our understanding of the biochemical mechanisms that mediate chemoreception in insects has been greatly improved after the discovery of olfactory and taste receptor proteins. However, the presence of soluble polypeptides in high concentration around the dendrites of sensory neurons still poses unanswered questions. More than 2 decades after their discovery and despite the wealth of structural information available, the physiological function of odorant-binding proteins is not well understood. More recently, members of a second family of soluble polypeptides, the chemosensory proteins, were also discovered in the lymph of chemosensilla. Here we review the structural properties of both classes of soluble proteins, their affinity to small ligands, and their expression in the different parts of the insect body and subcellular localisation. Finally, we discuss current ideas and models of the role of such proteins in insect chemoreception.
Topics: Amino Acid Sequence; Animals; Behavior, Animal; Chemoreceptor Cells; Consensus Sequence; Dendrites; Female; Gene Expression Regulation; Insect Proteins; Insecta; Ligands; Male; Models, Molecular; Molecular Sequence Data; Molecular Structure; Multigene Family; Neurons, Afferent; Odorants; Organ Specificity; Pheromones; Phylogeny; Protein Binding; Protein Conformation; Receptors, Odorant; Receptors, Pheromone; Sense Organs; Sequence Alignment; Sequence Homology, Amino Acid; Smell; Solubility; Species Specificity; Structure-Activity Relationship
PubMed: 16786224
DOI: 10.1007/s00018-005-5607-0 -
Journal of Anatomy Feb 2019The upper airways play important roles in respiratory defensive reflexes. Although solitary chemosensory cells and chemosensory cell clusters have been reported in the...
The upper airways play important roles in respiratory defensive reflexes. Although solitary chemosensory cells and chemosensory cell clusters have been reported in the laryngeal mucosa of mammalian species, the distribution and cellular morphology of chemosensory cells remain unclear. In the present study, the distribution and morphology of solitary chemosensory cells and chemosensory cell clusters were examined by immunofluorescence for GNAT3 on whole-mount preparations of the rat laryngeal mucosa. Electrophysiological experiments were performed to analyze the respiratory reflexes evoked by bitter stimuli to the laryngeal cavity. In the whole area of the laryngeal mucosa, the numbers of GNAT3-immunoreactive solitary chemosensory cells and chemosensory clusters were 421.0 ± 20.3 and 62.7 ± 6.9, respectively. GNAT3-immunoreactive solitary chemosensory cells were mainly distributed in the mucosa overlying epiglottic and arytenoid cartilage, and chemosensory clusters were mainly distributed on the edge of the epiglottis and aryepiglottic fold. GNAT3-immunoreactive solitary chemosensory cells were slender with elongated processes or had a flask-like/columnar shape. The number of GNAT3-immunoreactive cells in chemosensory clusters was 6.1 ± 0.4, ranging between 2 and 14 cells. GNAT3-immunoreactive cells in the cluster were variform and the tips of apical processes gathered at one point at the surface of the epithelium. The tips of apical cytoplasmic processes in solitary chemosensory cells and cells in the cluster were immunoreactive for espin, and faced the laryngeal cavity. Physiological experiments showed that the application of 10 mm quinine hydrochloride to the laryngeal cavity decreased respiratory frequency. The present results revealed the chemosensory field of the larynx and the morphological characteristics of the laryngeal chemosensory system for respiratory depression.
Topics: Animals; Chemoreceptor Cells; Laryngeal Mucosa; Male; Rats, Wistar; Reflex; Respiration; Transducin
PubMed: 30467855
DOI: 10.1111/joa.12914 -
Pflugers Archiv : European Journal of... May 2015Arterial chemoreceptors play a vital role in cardiorespiratory control by providing the brain with information regarding blood oxygen, carbon dioxide, and pH. The main... (Review)
Review
Arterial chemoreceptors play a vital role in cardiorespiratory control by providing the brain with information regarding blood oxygen, carbon dioxide, and pH. The main chemoreceptor, the carotid body, is composed of sensory (type 1) cells which respond to hypoxia or acidosis with a depolarising receptor potential which in turn activates voltage-gated calcium entry, neurosecretion and excitation of adjacent afferent nerves. The receptor potential is generated by inhibition of Twik-related acid-sensitive K(+) channel 1 and 3 (TASK1/TASK3) heterodimeric channels which normally maintain the cells' resting membrane potential. These channels are thought to be directly inhibited by acidosis. Oxygen sensitivity, however, probably derives from a metabolic signalling pathway. The carotid body, isolated type 1 cells, and all forms of TASK channel found in the type 1 cell, are highly sensitive to inhibitors of mitochondrial metabolism. Moreover, type1 cell TASK channels are activated by millimolar levels of MgATP. In addition to their role in the transduction of chemostimuli, type 1 cell TASK channels have also been implicated in the modulation of chemoreceptor function by a number of neurocrine/paracrine signalling molecules including adenosine, GABA, and serotonin. They may also be instrumental in mediating the depression of the acute hypoxic ventilatory response that occurs with some general anaesthetics. Modulation of TASK channel activity is therefore a key mechanism by which the excitability of chemoreceptors can be controlled. This is not only of physiological importance but may also offer a therapeutic strategy for the treatment of cardiorespiratory disorders that are associated with chemoreceptor dysfunction.
Topics: Acidosis; Animals; Calcium; Chemoreceptor Cells; Humans; Membrane Potentials; Oxygen; Potassium Channels, Tandem Pore Domain
PubMed: 25623783
DOI: 10.1007/s00424-015-1689-1