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Robert M Bradley - One of the best experts on this subject based on the ideXlab platform.
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Geniculate Ganglion Neurons are Multimodal and Variable in Receptive Field Characteristics
Neuroscience, 2017Co-Authors: Yusuke Yokota, Robert M BradleyAbstract:Abstract Afferent chorda tympani (CT) fibers innervating anterior tongue fungiform papillae have neuron cell bodies in the Geniculate Ganglion (GG). To characterize electrophysiological and receptive field properties, we recorded extracellular responses from single GG neurons to lingual application with chemical, thermal and mechanical stimuli. Receptive field size was mapped by electrical stimulation of individual fungiform papillae. Responses of GG neurons to room temperature chemical stimuli representing five taste qualities, and distilled water at 4 °C and mechanical stimulation were used. Based on responses to these stimuli, GG neurons were divided into CHEMICAL, CHEMICAL/THERMAL, THERMAL and TACTILE groups. Neurons in the CHEMICAL group responded to taste stimuli but not to either cold water or stroking stimuli. CHEMICAL/THERMAL neurons responded to both taste stimuli and cold water. THERMAL neurons responded only to cold water and TACTILE neurons responded only to light stroking stimuli. The receptive field sizes for CHEMICAL, and CHEMICAL/THERMAL neurons averaged five papillae exceeding the field size of THERMAL and TACTILE neurons which averaged about two papillae. Detailed analysis of the receptive field of CHEMICAL/THERMAL neurons revealed that within one field only a subset of the fungiform papillae making up the receptive field responded to the cold stimuli, whereas the other papillae responded only to chemical stimuli. These finding demonstrate that fungiform papilla are complex sensory organs with a multisensory function suggesting a unique role in detecting and sampling food components prior to ingestion.
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Receptive field size, chemical and thermal responses, and fiber conduction velocity of rat chorda tympani Geniculate Ganglion neurons.
Journal of neurophysiology, 2016Co-Authors: Yusuke Yokota, Robert M BradleyAbstract:Afferent chorda tympani (CT) fibers innervating taste and somatosensory receptors in fungiform papillae have neuron cell bodies in the Geniculate Ganglion (GG). The GG/CT fibers branch in the tongue to innervate taste buds in several fungiform papillae. To investigate receptive field characteristics of GG/CT neurons, we recorded extracellular responses from GG cells to application of chemical and thermal stimuli. Receptive field size was mapped by electrical stimulation of individual fungiform papillae. Response latency to electrical stimulation was used to determine fiber conduction velocity. Responses of GG neurons to lingual application of stimuli representing four taste qualities, and water at 4°C, were used to classify neuron response properties. Neurons classified as SALT, responding only to NaCl and NH4Cl, had a mean receptive field size of six papillae. Neurons classified as OTHER responded to salts and other chemical stimuli and had smaller mean receptive fields of four papillae. Neurons that responded to salts and cold stimuli, classified as SALT/THERMAL, and neurons responding to salts, other chemical stimuli and cold, classified as OTHER/THERMAL, had mean receptive field sizes of six and five papillae, respectively. Neurons responding only to cold stimuli, categorized as THERMAL, had receptive fields of one to two papillae located at the tongue tip. Based on conduction velocity most of the neurons were classified as C fibers. Neurons with large receptive fields had higher conduction velocities than neurons with small receptive fields. These results demonstrate that GG neurons can be distinguished by receptive field size, response properties and afferent fiber conduction velocity derived from convergent input of multiple taste organs.
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Characteristics of sodium currents in rat Geniculate Ganglion neurons
Journal of neurophysiology, 2011Co-Authors: Shiro Nakamura, Robert M BradleyAbstract:Geniculate Ganglion (GG) cell bodies of chorda tympani (CT), greater superficial petrosal (GSP), and posterior auricular (PA) nerves transmit orofacial sensory information to the rostral nucleus of the solitary tract. We have used whole cell recording to investigate the characteristics of the Na+ channels in isolated Fluorogold-labeled GG neurons that innervate different peripheral receptive fields. GG neurons expressed two classes of Na+ channels, TTX sensitive (TTX-S) and TTX resistant (TTX-R). The majority of GG neurons expressed TTX-R currents of different amplitudes. TTX-R currents were relatively small in 60% of the neurons but were large in 12% of the sampled population. In a further 28% of the neurons, TTX completely abolished all Na+ currents. Application of TTX completely inhibited action potential generation in all CT and PA neurons but had little effect on the generation of action potentials in 40% of GSP neurons. Most CT, GSP, and PA neurons stained positively with IB4, and 27% of the GSP neurons were capsaicin sensitive. The majority of IB4-positive GSP neurons with large TTX-R Na+ currents responded to capsaicin, whereas IB4-positive GSP neurons with small TTX-R Na+ currents were capsaicin insensitive. These data demonstrate the heterogeneity of GG neurons and indicate the existence of a subset of GSP neurons sensitive to capsaicin, usually associated with nociceptors. Since there are no reports of nociceptors in the GSP receptive field, the role of these capsaicin-sensitive neurons is not clear.
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Characteristics of calcium currents in rat Geniculate Ganglion neurons.
Journal of neurophysiology, 2010Co-Authors: Shiro Nakamura, Robert M BradleyAbstract:Geniculate Ganglion (GG) cell bodies of chorda tympani (CT), greater superficial petrosal (GSP), and posterior auricular (PA) nerves transmit orofacial sensory information to the rostral nucleus of the solitary tract (rNST). We used whole cell recording to study the characteristics of the Ca(2+) channels in isolated Fluorogold-labeled GG neurons that innervate different peripheral receptive fields. PA neurons were significantly larger than CT and GSP neurons, and CT neurons could be further subdivided based on soma diameter. Although all GG neurons possess both low voltage-activated (LVA) "T-type" and high voltage-activated (HVA) Ca(2+) currents, CT, GSP, and PA neurons have distinctly different Ca(2+) current expression patterns. Of GG neurons that express T-type currents, the CT and GSP neurons had moderate and PA neurons had larger amplitude T-type currents. HVA Ca(2+) currents in the GG neurons were separated into several groups using specific Ca(2+) channel blockers. Sequential applications of L, N, and P/Q-type channel antagonists inhibited portions of Ca(2+) current in all CT, GSP, and PA neurons to a different extent in each neuron group. No difference was observed in the percentage of L- and N-type Ca(2+) currents reduced by the antagonists in CT, GSP, and PA neurons. Action potentials in GG neurons are followed by a Ca(2+) current initiated after depolarization (ADP) that may influence intrinsic firing patterns. These results show that based on Ca(2+) channel expression the GG contains a heterogeneous population of sensory neurons possibly related to the type of sensory information they relay to the rNST.
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Embryonic Geniculate Ganglion neurons in culture have neurotrophin-specific electrophysiological properties.
Neuroscience, 2003Co-Authors: Solaiman M. Al-hadlaq, Robert M Bradley, Donald K. Maccallum, Charlotte M. MistrettaAbstract:Geniculate Ganglion neurons provide a major source of innervation to mammalian taste organs, including taste buds in the soft palate and in fungiform papillae on the anterior two thirds of the tongue. In and around the fungiform papillae, before taste buds form, neurotrophin mRNAs are expressed in selective spatial and temporal patterns. We hypothesized that neurotrophins would affect electrophysiological properties in embryonic Geniculate neurons. Ganglia were explanted from rats at gestational day 16, when growing neurites have entered the papilla core, and maintained in culture with added brain-derived neurotrophic factor (BDNF), neurotrophin 4 (NT4), nerve growth factor (NGF) or neurotrophin 3 (NT3). Neuron survival with BDNF or NT4 was about 80%, whereas with NGF or NT3 less than 15% of neurons survived over 6 days in culture. Whole cell recordings from neurons in Ganglion explants with each neurotrophin condition demonstrated distinctive neurophysiological properties related to specific neurotrophins. Geniculate neurons cultured with either BDNF or NT4 had similar passive-membrane and action potential properties, but these characteristics were significantly different from those of neurons cultured with NGF or NT3. NGF-maintained neurons had features of increased excitability including a higher resting membrane potential and a lower current threshold for the action potential. About 70% of neurons produced repetitive action potentials at threshold. Furthermore, compared with neurons cultured with other neurotrophins, a decreased proportion had an inflection on the falling phase of the action potential. NT3-maintained neurons had action potentials that were of relatively large amplitude and short duration, with steep rising and falling slopes. In addition, about 20% responded with a repetitive train of action potentials at threshold. In contrast, with BDNF or NT4 repetitive action potential trains were not observed. The data demonstrate different neurophysiological properties in developing Geniculate Ganglion neurons maintained with specific neurotrophins. Therefore, we suggest that neurotrophins might influence acquisition of distinctive neurophysiological properties in embryonic Geniculate neurons that are fundamental to the formation of peripheral taste circuits and a functioning taste system.
Robin F. Krimm - One of the best experts on this subject based on the ideXlab platform.
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The transcription factor Phox2b distinguishes between oral and non-oral sensory neurons in the Geniculate Ganglion.
The Journal of comparative neurology, 2017Co-Authors: Lisa Ohman-gault, Tao Huang, Robin F. KrimmAbstract:Many basic characteristics of gustatory neurons remain unknown, partly due to the absence of specific markers. Some neurons in the Geniculate Ganglion project to taste regions in the oral cavity, whereas others innervate the outer ear. We hypothesized that the transcription factor Phox2b would identify oral cavity-projecting neurons in the Geniculate Ganglion. To test this possibility, we characterized mice in which Phox2b-Cre mediated gene recombination labeled neurons with tdTomato. Nerve labeling revealed that all taste neurons projecting through the chorda tympani (27%) and greater superficial petrosal nerves (15%) expressed Phox2b during development, whereas non-oral somatosensory neurons (58%) in the Geniculate Ganglion did not. We found tdTomato-positive innervation within all taste buds. Most (57%) of the fungiform papillae had labeled innervation only in taste buds, whereas 43% of the fungiform papillae also had additional labeled innervation to the papilla epithelium. Chorda tympani nerve transection eliminated all labeled innervation to taste buds, but most of the additional innervation in the fungiform papillae remained. Some of these additional fibers also expressed tyrosine hydroxylase, suggesting a sympathetic origin. Consistent with this, both sympathetic and parasympathetic fibers innervating blood vessels and salivary glands contained tdTomato labeling. Phox2b-tdTomato labels nerve fascicles in the tongue of the developing embryo and demonstrates a similar stereotyped branching pattern DiI-labeling.
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BDNF is required for the survival of differentiated Geniculate Ganglion neurons.
Developmental biology, 2010Co-Authors: Ami V. Patel, Robin F. KrimmAbstract:In mice lacking functional brain-derived neurotrophic factor (BDNF), the number of Geniculate Ganglion neurons, which innervate taste buds, is reduced by one-half. Here, we determined how and when BDNF regulates the number of neurons in the developing Geniculate Ganglion. The loss of Geniculate neurons begins at embryonic day 13.5 (E13.5) and continues until E18.5 in BDNF-null mice. Neuronal loss in BDNF-null mice was prevented by the removal of the pro-apoptotic gene Bax. Thus, BDNF regulates embryonic Geniculate neuronal number by preventing cell death rather than promoting cell proliferation. The number of neurofilament positive neurons expressing activated caspase-3 increased on E13.5 in bdnf(-/-) mice, compared to wild-type mice, demonstrating that differentiated neurons were dying. The axons of Geniculate neurons approach their target cells, the fungiform papillae, beginning on E13.5, at which time we found robust BDNF(LacZ) expression in these targets. Altogether, our findings establish that BDNF produced in peripheral target cells regulates the survival of early Geniculate neurons by inhibiting cell death of differentiated neurons on E13.5 of development. Thus, BDNF acts as a classic target-derived growth factor in the developing taste system.
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Mice lacking the p75 receptor fail to acquire a normal complement of taste buds and Geniculate Ganglion neurons by adulthood.
The anatomical record. Part A Discoveries in molecular cellular and evolutionary biology, 2006Co-Authors: Robin F. KrimmAbstract:Brain derived neurotrophic factor and neurotrophin-4 are required for normal taste bud development. Although these neurotrophins normally function via the tyrosine kinase receptor, trkB, they also bind to the pan-neurotrophin receptor, p75. The goal of the present study was to determine whether the p75 receptor is required for the development or maintenance of a full complement of adult taste buds. Mice with p75 null mutations lose 34% of their circumvallate taste buds, 36% of their fungiform papillae, and 26% of their fungiform taste buds by adulthood. The reduction of taste buds in the adult circumvallate papilla was similar to that observed previously at postnatal day 7 ((Fan et al., 2004). Taken together, these findings indicate that the p75 receptor is critical for the development of a full complement of taste buds, but is not required for maintenance of circumvallate taste buds in adulthood. Immunolabeling for p75 was not observed in taste buds, indicating that p75 signaling influences taste bud number indirectly. However, Geniculate Ganglion neurons, which provides innervation to fungiform taste buds, express the p75 receptor. Mice with p75-null mutations also have fewer neurons in the Geniculate Ganglion. Together, these results suggest that survival of Geniculate neurons is essential for the development of a full complement of taste buds.
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Innervation of single fungiform taste buds during development in rat.
The Journal of comparative neurology, 1998Co-Authors: Robin F. Krimm, David L. HillAbstract:To determine whether the innervation of taste buds changes during postnatal development, the number of Geniculate Ganglion cells that innervated single fungiform taste buds were quantified in the tip- and midregions of the tongue of adult and developing rats. There was substantial variation in both the size of individual taste buds and number of Geniculate Ganglion cells that innervated them. Importantly, taste bud morphology and innervation were highly related. Namely, the number of labeled Geniculate Ganglion cells that innervated a taste bud was highly correlated with the size of the taste bud (r 5 0.91, P , .0003): The larger the taste bud, the more Geniculate Ganglion cells that innervated it. The relationship between Ganglion cell number and taste bud volume emerged during the first 40 days postnatal. Whereas there was no difference in the average number of Ganglion cells that innervated individual taste buds in rats aged 10 days postnatal through adulthood, taste bud volumes increased progressively between 10 and 40 days postnatal, at which age taste bud volumes were similar to adults. The maturation of taste bud size was accompanied by the emergence of the relationship between taste bud volume and number of innervating neurons. Specifically, there was no correlation between taste bud size and number of innervating Geniculate Ganglion cells in 10-, 20-, or 30-day-old rats, whereas taste bud size and the number of innervating Ganglion cells in 40-day-old rats were positively correlated (r 5 .80, P , .002). Therefore, the relationship between taste bud size and number of innervating Ganglion cells develops over a prolonged postnatal period and is established when taste buds grow to their adult size. J. Comp. Neurol. 398:13‐24, 1998. r 1998 Wiley-Liss, Inc. Indexing terms: taste bud; Geniculate Ganglion; sensory afferents; fluorescent tracers; tongue
Robert J. Contreras - One of the best experts on this subject based on the ideXlab platform.
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Response Latency to Lingual Taste Stimulation Distinguishes Neuron Types Within the Geniculate Ganglion
Journal of neurophysiology, 2010Co-Authors: Joseph M. Breza, Alexandre A. Nikonov, Robert J. ContrerasAbstract:The purpose of this study was to investigate the role of response latency in discrimination of chemical stimuli by Geniculate Ganglion neurons in the rat. Accordingly, we recorded single-cell 5-s responses from Geniculate Ganglion neurons (n = 47) simultaneously with stimulus-evoked summated potentials (electrogustogram; EGG) from the anterior tongue to signal when the stimulus contacted the lingual epithelium. Artificial saliva served as the rinse solution and solvent for all stimuli [(0.5 M sucrose, 0.03-0.5 M NaCl, 0.01 M citric acid, and 0.02 M quinine hydrochloride (QHCl)], 0.1 M KCl as well as for 0.1 M NaCl +1 μM benzamil. Cluster analysis separated neurons into four groups (sucrose specialists, NaCl specialists, NaCl/QHCl generalists and acid generalists). Artificial saliva elevated spontaneous firing rate and response frequency of all neurons. As a rule, Geniculate Ganglion neurons responded with the highest frequency and shortest latency to their best stimulus with acid generalist the only exception. For specialist neurons and NaCl/QHCl generalists, the average response latency to the best stimulus was two to four times shorter than the latency to secondary stimuli. For NaCl-specialist neurons, response frequency increased and response latency decreased systematically with increasing NaCl concentration; benzamil significantly decreased NaCl response frequency and increased response latency. Acid-generalist neurons had the highest spontaneous firing rate and were the only group that responded consistently to citric acid and KCl. For many acid generalists, a citric-acid-evoked inhibition preceded robust excitation. We conclude that response latency may be an informative coding signal for peripheral chemosensory neurons.
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Monosodium Glutamate but not Linoleic Acid Differentially Activates Gustatory Neurons in the Rat Geniculate Ganglion
Chemical senses, 2007Co-Authors: Joseph M. Breza, Kathleen S. Curtis, Robert J. ContrerasAbstract:To date, only one study has examined responses to monosodium glutamate (MSG) from gustatory neurons in the rat Geniculate Ganglion and none to free fatty acids. Accordingly, we recorded single-cell responses from Geniculate Ganglion gustatory neurons in anesthetized male rats to MSG and linoleic acid (LA), as well as to sucrose, NaCl, citric acid, and quinine hydrochloride. None of the 52 neurons responded to any LA concentration. In contrast, both narrowly tuned groups of gustatory neurons (sucrose specialists and NaCl specialists) responded to MSG, as did 2 of the broadly tuned groups (NaCl generalistI and acid generalists). NaCl-generalistII neurons responded only to the highest MSG concentration and only at low rates. No neuron type responded best to MSG; rather, responses to 0.1 M MSG were significantly less than those to NaCl for Na + -sensitive neurons and to sucrose for sucrose specialists. Interestingly, most Na + -sensitive neurons responded to 0.3 M MSG at levels comparable with those to 0.1 M NaCl, whereas sucrose specialists responded to 0.1 M MSG despite being unresponsive to NaCl. These results suggest that the stimulatory effect of MSG involves activation of sweet- or salt-sensitive receptors. We propose that glutamate underlies the MSG response of sucrose specialists, whereas Na + -sensitive neurons respond to the sodium cation. For the latter neuron groups, the large glutamate anion may reduce the driving force for sodium through epithelial channels on taste cell membranes. The observed concentration-dependent responses are consistent with this idea, as are cross-adaptation studies using 0.1 M concentrations of MSG and NaCl in subsets of these Na + -sensitive neurons.
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Temperature Modulates Taste Responsiveness and Stimulates Gustatory Neurons in the Rat Geniculate Ganglion
Journal of neurophysiology, 2005Co-Authors: Joseph M. Breza, Kathleen S. Curtis, Robert J. ContrerasAbstract:In humans, temperature influences taste intensity and quality perception, and thermal stimulation itself may elicit taste sensations. However, peripheral coding mechanisms of taste have generally been examined independently of the influence of temperature. In anesthetized rats, we characterized the single-cell responses of Geniculate Ganglion neurons to 0.5 M sucrose, 0.1 M NaCl, 0.01 M citric acid, and 0.02 M quinine hydrochloride at a steady, baseline temperature (adapted) of 10, 25, and 40 degrees C; gradual cooling and warming (1 degrees C/s change in water temperature >5 s) from an adapted tongue temperature of 25 degrees C; gradual cooling from an adapted temperature of 40 degrees C; and gradual warming from an adapted temperature of 10 degrees C. Hierarchical cluster analysis of the taste responses at 25 degrees C divided 50 neurons into two major categories of narrowly tuned (Sucrose-specialists, NaCl-specialists) and broadly tuned (NaCl-generalists(I), NaCl- generalists(II), Acid-generalists, and QHCl-generalists) groups. NaCl specialists were excited by cooling from 25 to 10 degrees C and inhibited by warming from 10 to 25 degrees C. Acid-generalists were excited by cooling from 40 to 25 degrees C but not from 25 to 10 degrees C. In general, the taste responses of broadly tuned neurons decreased systematically to all stimuli with decreasing adapted temperatures. The response selectivity of Sucrose-specialists for sucrose and NaCl-specialists for NaCl was unaffected by adapted temperature. However, Sucrose-specialists were unresponsive to sucrose at 10 degrees C, whereas NaCl-specialists responded equally to NaCl at all adapted temperatures. In conclusion, we have shown that temperature modulates taste responsiveness and is itself a stimulus for activation in specific types of peripheral gustatory neurons.
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Gustatory neuron types in rat Geniculate Ganglion.
Journal of neurophysiology, 1999Co-Authors: Robert F. Lundy, Robert J. ContrerasAbstract:We used extracellular single-cell recording procedures to characterize the chemical and thermal sensitivity of the rat Geniculate Ganglion to lingual stimulation, and to examine the effects of spec...
David L. Hill - One of the best experts on this subject based on the ideXlab platform.
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Transcriptomes and neurotransmitter profiles of classes of gustatory and somatosensory neurons in the Geniculate Ganglion
Nature communications, 2017Co-Authors: Gennady Dvoryanchikov, Stephen D. Roper, David L. Hill, Damian Hernandez, Jennifer K. Roebber, Nirupa ChaudhariAbstract:Taste 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. Here, we report single cell RNA sequencing of Geniculate Ganglion neurons. Using unbiased transcriptome analyses, we show a pronounced separation between two major clusters which, by anterograde labeling, correspond to gustatory and somatosensory neurons. Among the gustatory neurons, three subclusters are present, each with its own complement of transcription factors and neurotransmitter response profiles. The smallest subcluster expresses both gustatory- and mechanosensory-related genes, suggesting a novel type of sensory neuron. We identify several markers to help dissect the functional distinctions among gustatory neurons and address questions regarding target interactions and taste coding. Characterization of gustatory neural pathways has suffered due to a lack of molecular markers. Here, the authors report single cell RNA sequencing and unbiased transcriptome analyses to reveal major distinctions between gustatory and somatosensory neurons and subclusters of gustatory neurons with unique molecular and functional profiles.
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Each sensory nerve arising from the Geniculate Ganglion expresses a unique fingerprint of neurotrophin and neurotrophin receptor genes
Journal of neuroscience research, 2004Co-Authors: Albert I. Farbman, Nick A. Guagliardo, Suzanne I. Sollars, David L. HillAbstract:Neurons in the Geniculate Ganglion, like those in other sensory ganglia, are dependent on neurotrophins for survival. Most Geniculate Ganglion neurons innervate taste buds in two regions of the tongue and two regions of the palate; the rest are cutaneous nerves to the skin of the ear. We investigated the expression of four neurotrophins, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3), and NT-4, and five neurotrophin receptors, trkA, trkB, trkC, p75, and truncated trkB (Trn-B) in single sensory neurons of the adult rat Geniculate Ganglion associated with the five innervation fields. For fungiform papillae, a glass pipette containing biotinylated dextran was placed over the target papilla and the tracer was iontophoresed into the target papilla. For the other target fields, Fluoro-Gold was microinjected. After 3 days, Geniculate ganglia were harvested, sectioned, and treated histochemically (for biotinylated dextran) or immunohistochemically (for Fluoro-Gold) to reveal the neurons containing the tracer. Single labeled neurons were harvested from the slides and subjected to RNA amplification and RT-PCR to reveal the neurotrophin or neurotrophin receptor genes that were expressed. Neurons projecting from the Geniculate Ganglion to each of the five target fields had a unique expression profile of neurotrophin and neurotrophic receptor genes. Several individual neurons expressed more than one neurotrophin receptor or more than one neurotrophin gene. Although BDNF is significantly expressed in taste buds, its primary high affinity receptor, trkB, was not prominently expressed in the neurons. The results are consistent with the interpretation that at least some, perhaps most, of the trophic influence on the sensory neurons is derived from the neuronal somata, and the trophic effect is paracrine or autocrine, rather than target derived. The BDNF in the taste bud may also act in a paracrine or autocrine manner on the trkB expressed in taste buds, as shown by others.
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Innervation of single fungiform taste buds during development in rat.
The Journal of comparative neurology, 1998Co-Authors: Robin F. Krimm, David L. HillAbstract:To determine whether the innervation of taste buds changes during postnatal development, the number of Geniculate Ganglion cells that innervated single fungiform taste buds were quantified in the tip- and midregions of the tongue of adult and developing rats. There was substantial variation in both the size of individual taste buds and number of Geniculate Ganglion cells that innervated them. Importantly, taste bud morphology and innervation were highly related. Namely, the number of labeled Geniculate Ganglion cells that innervated a taste bud was highly correlated with the size of the taste bud (r 5 0.91, P , .0003): The larger the taste bud, the more Geniculate Ganglion cells that innervated it. The relationship between Ganglion cell number and taste bud volume emerged during the first 40 days postnatal. Whereas there was no difference in the average number of Ganglion cells that innervated individual taste buds in rats aged 10 days postnatal through adulthood, taste bud volumes increased progressively between 10 and 40 days postnatal, at which age taste bud volumes were similar to adults. The maturation of taste bud size was accompanied by the emergence of the relationship between taste bud volume and number of innervating neurons. Specifically, there was no correlation between taste bud size and number of innervating Geniculate Ganglion cells in 10-, 20-, or 30-day-old rats, whereas taste bud size and the number of innervating Ganglion cells in 40-day-old rats were positively correlated (r 5 .80, P , .002). Therefore, the relationship between taste bud size and number of innervating Ganglion cells develops over a prolonged postnatal period and is established when taste buds grow to their adult size. J. Comp. Neurol. 398:13‐24, 1998. r 1998 Wiley-Liss, Inc. Indexing terms: taste bud; Geniculate Ganglion; sensory afferents; fluorescent tracers; tongue
Hakan Özalp - One of the best experts on this subject based on the ideXlab platform.
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Growth dynamic of the Geniculate Ganglion in children: a retrospective computed tomography study
Surgical and Radiologic Anatomy, 2020Co-Authors: Orhan Beger, Osman Erdoğan, Engin Kara, Yusuf Vayisoglu, Onur Ismi, Kemal Görür, Salahi Barış Özgüvenli, Rüya Zereyalp, Vural Hamzaoğlu, Hakan ÖzalpAbstract:Purpose The main aim of this retrospective computed tomography (CT) study was to examine the morphometric development of the Geniculate Ganglion (GG) in children aged between 1 and 18 years for surgical approaches. Methods This study was placed on 41 patients (20 females and 21 males) including cochlear implantation cases aged from one to 18 (at mean, 6.44 ± 5.79) years. All the measurements belonging to the length, width and area of GG were performed with a CT scanner. Results The morphometric values of GG were not different in terms of sex or side, statistically ( p > 0.05). The length ( p = 0.155) of GG was not correlated with the increasing ages from one to 18 years; however, its area ( p
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Growth dynamic of the Geniculate Ganglion in children: a retrospective computed tomography study
Surgical and radiologic anatomy : SRA, 2019Co-Authors: Orhan Beger, Osman Erdoğan, Engin Kara, Yusuf Vayisoglu, Onur Ismi, Kemal Görür, Salahi Barış Özgüvenli, Rüya Zereyalp, Vural Hamzaoğlu, Hakan ÖzalpAbstract:Purpose The main aim of this retrospective computed tomography (CT) study was to examine the morphometric development of the Geniculate Ganglion (GG) in children aged between 1 and 18 years for surgical approaches.
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Radioanatomic Assessment of the Geniculate Ganglion Dehiscence and Dimension: A Cadaveric Study.
World neurosurgery, 2019Co-Authors: Vural Hamzaoğlu, Orhan Beger, Osman Erdoğan, Engin Kara, Yusuf Vayisoglu, Hakan Özalp, Pourya Taghipour, Derya Karatas, Emel Avci, Ahmet DagtekinAbstract:Abstract Objective The main aim of this study placed on cadavers was to compare the data related to Geniculate Ganglion (GG) dehiscence and dimension obtained from computed tomography (CT) with dissection values. Methods This study was conducted on 20 temporal bones obtained from 10 cadavers (4 females and 6 males) aged between 45-92 (71.50±15.98) years. All the measurements related to GG dimension were performed with a CT scanner and microdissection. Results The size of GG including its area, length and width did not show statistical significant differences in terms of sexes, sides and assessment methods (CT and cadaveric dissections). The dehiscent GG was observed in 6 (30%) and 5 (25%) out of 20 temporal bones in CT and cadaveric dissections, respectively. The presence and absence of GG dehiscence in CT and dissection were similar in 75%. Conclusions Our findings based on dissection data suggested that radiological evaluation of dehiscent GG detection might be erroneous by 25%, which proved that surgeons should be careful when lifting the dura to prevent GG injury during middle cranial fossa surgical approaches. On the other hand, there was no statistical difference between CT and dissection measurements related to GG dimension.