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David L Hill - One of the best experts on this subject based on the ideXlab platform.
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impact of Chorda Tympani nerve injury on cell survival axon maintenance and morphology of the Chorda Tympani nerve terminal field in the nucleus of the solitary tract
The Journal of Comparative Neurology, 2012Co-Authors: Rebecca Reddaway, Andrew W Davidow, Sarah L Deal, David L HillAbstract:Chorda Tympani nerve transection (CTX) has been useful to study the relationship between nerve and taste buds in fungiform papillae. This work demonstrated that the morphological integrity of taste buds depends on their innervation. Considerable research focused on the effects of CTX on peripheral gustatory structures, but much less research has focused on the central effects. Here, we explored how CTX affects ganglion cell survival, maintenance of injured peripheral axons, and the Chorda Tympani nerve terminal field organization in the nucleus of the solitary tract (NTS). After CTX in adult rats, the Chorda Tympani nerve was labeled with biotinylated dextran amine at 3, 7, 14, 30, and 60 days post-CTX to allow visualization of the terminal field associated with peripheral processes. There was a significant and persistent reduction of the labeled Chorda Tympani nerve terminal field volume and density in the NTS following CTX. Compared with controls, the volume of the labeled terminal field was not altered at 3 or 7 days post-CTX; however, it was significantly reduced by 44% and by 63% at 30 and 60 days post-CTX, respectively. Changes in the density of labeled terminal field in the NTS paralleled the terminal field volume results. The dramatic decrease in labeled terminal field size post-CTX cannot be explained by a loss of geniculate ganglion neurons or degeneration of central axons. Instead, the function and/or maintenance of the peripheral axonal process appear to be affected. These new results have implications for long-term functional and behavioral alterations.
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Chorda Tympani nerve terminal field maturation and maintenance is severely altered following changes to gustatory nerve input to the nucleus of the solitary tract
The Journal of Neuroscience, 2011Co-Authors: Stephen L. Corson, David L HillAbstract:Neural competition among multiple inputs can affect the refinement and maintenance of terminal fields in sensory systems. In the rat gustatory system, the Chorda Tympani, greater superficial petrosal, and glossopharyngeal nerves have distinct but overlapping terminal fields in the first central relay, the nucleus of the solitary tract. This overlap is largest at early postnatal ages followed by a significant refinement and pruning of the fields over a 3 week period, suggesting that competitive mechanisms underlie the pruning. Here, we manipulated the putative competitive interactions among the three nerves by sectioning the greater superficial petrosal and glossopharyngeal nerves at postnatal day 15 (P15), P25, or at adulthood, while leaving the Chorda Tympani nerve intact. The terminal field of the Chorda Tympani nerve was assessed 35 d following nerve sections, a period before the sectioned nerves functionally regenerated. Regardless of the age when the nerves were cut, the Chorda Tympani nerve terminal field expanded to a volume four times larger than sham controls. Terminal field density measurements revealed that the expanded terminal field was similar to P15 control rats. Thus, it appears that the Chorda Tympani nerve terminal field defaults to its early postnatal field size and shape when the nerves with overlapping fields are cut, and this anatomical plasticity is retained into adulthood. These findings not only demonstrate the dramatic and lifelong plasticity in the central gustatory system, but also suggest that corresponding changes in functional and taste-related behaviors will accompany injury-induced changes in brainstem circuits.
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nerve target interactions in the gustatory system following unilateral Chorda Tympani nerve section
Chemical Senses, 2005Co-Authors: David L HillAbstract:Although much effort has been directed at examining the morphological characteristics of denervated and regenerated taste buds, relatively little is known about the physiology of reinnervated taste cells (Vintschgau and Honigschmied, 1876; Guth, 1957; Fujimoto and Murray, 1970; Cheal and Oakley, 1977; Whitehead et al., 1987). Over 25 years ago, Oakley (Cheal et al., 1977) and colleagues found that some Chorda Tympani fibers reinnervated fungiform papillae on the gerbil’s anterior tongue in <2 weeks post-sectioning. Studies that examined recovery of taste function following nerve damage (Cain et al., 1996; Cheal et al., 1977; Ninomiya, 1998; Yasumatsu et al., 2003) indicate that regenerated taste nerves generally recover normal function after progressing through a transitional period. Only relatively recently has the impact of environment on the adult regenerating taste system been explored. Regenerating taste receptor cells in adult rats are susceptible to dietary influences (Hill and Phillips, 1994). Sectioning the Chorda Tympani unilaterally in rats fed a sodium-restricted diet at adulthood resulted in a regenerated nerve that had attenuated responses to sodium salts. Responses to other stimuli were unaffected. In addition, there were other, novel effects. In the same rat, the contralateral, uncut nerve was supersensitive to sodium salts. The supersensitivity developed progressively following an initial
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time course of morphological alterations of fungiform papillae and taste buds following Chorda Tympani transection in neonatal rats
Journal of Neurobiology, 2002Co-Authors: Suzanne I Sollars, Peter C. Smith, David L HillAbstract:The time course of structural changes in fungiform papillae was analyzed in rats that received unilateral Chorda Tympani nerve transection at 10 days of age. Morphological differences between intact and denervated sides of the tongue were first observed at 8 days postsection, with an increase in the number of fungiform papillae that did not have a pore. In addition, the first papilla with a filiform-like appearance was noted on the denervated side at 8 days postsectioning. By 11 days after surgery, the total number of papillae and the number of papillae with a pore were significantly lower on the transected side of the tongue as compared to the intact side. At 50 days postsection, there was an average of 70.5 fungiform papillae on the intact side and a mean of only 20.8 fungiform papillae the denervated side. Of those few remaining papillae on the cut side, an average of 13.5 papillae were categorized as filiform-like, while no filiform-like papillae occurred on the intact side. Significant reduction in taste bud volume was noted at 4 days posttransection and further decrements in taste bud volume were noted at 8 and 30 days postsection. Electron microscopy of the lingual branch of the trigeminal nerve from adult rats that received neonatal Chorda Tympani transection showed normal numbers of both myelinated and unmyelinated fibers. Thus, in addition to the well-characterized dependence of taste bud maintenance on the Chorda Tympani nerve, the present study shows an additional role of the Chorda Tympani nerve in papilla maintenance during early postnatal development.
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Time Course of Morphological Alterations of Fungiform Papillae and Taste Buds Following Chorda Tympani Transection in Neonatal Rats
2001Co-Authors: Suzanne I Sollars, Peter C. Smith, David L HillAbstract:ABSTRACT: The time course of structural changes in fungiform papillae was analyzed in rats that received unilateral Chorda Tympani nerve transection at 10 days of age. Morphological differences between intact and denervated sides of the tongue were first observed at 8 days postsection, with an increase in the number of fungiform papillae that did not have a pore. In addition, the first papilla with a filiform-like appearance was noted on the denervated side at 8 days postsectioning. By 11 days after surgery, the total number of papillae and the number of papillae with a pore were significantly lower on the transected side of the tongue as compared to the intact side. At 50 days postsection, there was an average of 70.5 fungiform papillae on the intact side and a mean of only 20.8 fungiform papillae the denervated side. Of those few remaining papillae on the cut side, an average of 13.5 papillae were categorized as filiform-like, while no filiform-like papillae occurred on the in-tact side. Significant reduction in taste bud volume was noted at 4 days posttransection and further decrements in taste bud volume were noted at 8 and 30 days post-section. Electron microscopy of the lingual branch of the trigeminal nerve from adult rats that received neonatal Chorda Tympani transection showed normal numbers of both myelinated and unmyelinated fibers. Thus, in ad-dition to the well-characterized dependence of taste bud maintenance on the Chorda Tympani nerve, the present study shows an additional role of the Chorda Tympani nerve in papilla maintenance during early postnatal develop
Suzanne I Sollars - One of the best experts on this subject based on the ideXlab platform.
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taste activity in the parabrachial region in adult rats following neonatal Chorda Tympani transection
Journal of Neurophysiology, 2021Co-Authors: Louis J Martin, Joseph M Breza, Suzanne I SollarsAbstract:Early and chronic loss of taste input from the Chorda Tympani is associated with abnormal taste behaviors. We found that compared to when the Chorda Tympani is sectioned acutely, chronic nerve loss...
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Chorda Tympani nerve transection at different developmental ages produces differential effects on taste bud volume and papillae morphology in the rat
Journal of Neurobiology, 2005Co-Authors: Suzanne I SollarsAbstract:Chorda Tympani nerve transection (CTX) results in morphological changes to fungiform papillae and associated taste buds. When transection occurs during neonatal development in the rat, the effects on fungiform taste bud and papillae structure are markedly more severe than observed following a comparable surgery in the adult rat. The present study examined the potential “sensitive period” for morphological modifications to tongue epithelium following CTX. Rats received unilateral transection at 65, 30, 25, 20, 15, 10, or 5 days of age. With each descending age at the time of transection, the effects on the structural integrity of fungiform papillae were more severe. Significant losses in total number of taste buds and filiform-like papillae were observed when transection occurred 5–30 days of age. Significant reduction in the number of taste pores was indicated at every age of transection. Another group of rats received Chorda Tympani transection at 10, 25, or 65 days of age to determine if the time course of taste bud degeneration differed depending on the age of the rat at the time of transection. Taste bud volumes differed significantly from intact sides of the tongue at 2, 8, and 50 days posttransection after CTX at 65 days of age. Volume measurements did not differ 2 days posttransection after CTX at 10 or 25 days of age, but were significantly reduced at the other time points. Findings demonstrate a transitional period throughout development wherein fungiform papillae are highly dependent upon the Chorda Tympani for maintenance of morphological integrity. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005
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time course of morphological alterations of fungiform papillae and taste buds following Chorda Tympani transection in neonatal rats
Journal of Neurobiology, 2002Co-Authors: Suzanne I Sollars, Peter C. Smith, David L HillAbstract:The time course of structural changes in fungiform papillae was analyzed in rats that received unilateral Chorda Tympani nerve transection at 10 days of age. Morphological differences between intact and denervated sides of the tongue were first observed at 8 days postsection, with an increase in the number of fungiform papillae that did not have a pore. In addition, the first papilla with a filiform-like appearance was noted on the denervated side at 8 days postsectioning. By 11 days after surgery, the total number of papillae and the number of papillae with a pore were significantly lower on the transected side of the tongue as compared to the intact side. At 50 days postsection, there was an average of 70.5 fungiform papillae on the intact side and a mean of only 20.8 fungiform papillae the denervated side. Of those few remaining papillae on the cut side, an average of 13.5 papillae were categorized as filiform-like, while no filiform-like papillae occurred on the intact side. Significant reduction in taste bud volume was noted at 4 days posttransection and further decrements in taste bud volume were noted at 8 and 30 days postsection. Electron microscopy of the lingual branch of the trigeminal nerve from adult rats that received neonatal Chorda Tympani transection showed normal numbers of both myelinated and unmyelinated fibers. Thus, in addition to the well-characterized dependence of taste bud maintenance on the Chorda Tympani nerve, the present study shows an additional role of the Chorda Tympani nerve in papilla maintenance during early postnatal development.
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Time Course of Morphological Alterations of Fungiform Papillae and Taste Buds Following Chorda Tympani Transection in Neonatal Rats
2001Co-Authors: Suzanne I Sollars, Peter C. Smith, David L HillAbstract:ABSTRACT: The time course of structural changes in fungiform papillae was analyzed in rats that received unilateral Chorda Tympani nerve transection at 10 days of age. Morphological differences between intact and denervated sides of the tongue were first observed at 8 days postsection, with an increase in the number of fungiform papillae that did not have a pore. In addition, the first papilla with a filiform-like appearance was noted on the denervated side at 8 days postsectioning. By 11 days after surgery, the total number of papillae and the number of papillae with a pore were significantly lower on the transected side of the tongue as compared to the intact side. At 50 days postsection, there was an average of 70.5 fungiform papillae on the intact side and a mean of only 20.8 fungiform papillae the denervated side. Of those few remaining papillae on the cut side, an average of 13.5 papillae were categorized as filiform-like, while no filiform-like papillae occurred on the in-tact side. Significant reduction in taste bud volume was noted at 4 days posttransection and further decrements in taste bud volume were noted at 8 and 30 days post-section. Electron microscopy of the lingual branch of the trigeminal nerve from adult rats that received neonatal Chorda Tympani transection showed normal numbers of both myelinated and unmyelinated fibers. Thus, in ad-dition to the well-characterized dependence of taste bud maintenance on the Chorda Tympani nerve, the present study shows an additional role of the Chorda Tympani nerve in papilla maintenance during early postnatal develop
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neonatal Chorda Tympani transection permanently disrupts fungiform taste bud and papilla structure in the rat
Physiology & Behavior, 2000Co-Authors: Suzanne I Sollars, Ilene L BernsteinAbstract:Abstract The present report examined the morphology of fungiform papillae in adult rats that received bilateral Chorda Tympani transection at 10 days of age. Tongue tissue was examined using surface-structure analysis. Counts were made of fungiform papillae with a pore, fungiform papillae with no pore and fungiform papillae with a keratinized conical surface; a feature referred to as “filiform-like.” Neonatal Chorda Tympani nerve transection resulted not only in a loss of taste buds but also in a permanent loss in numbers of fungiform papillae. Compared with an average of 152 fungiform papillae in sham-operated control rats, there was an average of only 54 fungiform papillae after neonatal Chorda Tympani transection. Nearly 80% of these fungiform papillae in neonatal Chorda Tympani transected rats were filiform-like. No filiform-like papillae were noted in sham-operated rats. These results suggest that the Chorda Tympani nerve is necessary during an early postnatal period of development to maintain normal fungiform papillae morphology.
Vicktoria Danilova - One of the best experts on this subject based on the ideXlab platform.
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Responses of single Chorda Tympani taste fibers of the calf (Bos taurus).
Chemical senses, 2010Co-Authors: Göran Hellekant, Thomas W. Roberts, Donald Elmer, Tiffany Cragin, Vicktoria DanilovaAbstract: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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comparison of the responses of the Chorda Tympani and glossopharyngeal nerves to taste stimuli in c57bl 6j mice
BMC Neuroscience, 2003Co-Authors: Vicktoria Danilova, Göran HellekantAbstract:Background Recent progress in discernment of molecular pathways of taste transduction underscores the need for comprehensive phenotypic information for the understanding of the influence of genetic factors in taste. To obtain information that can be used as a base line for assessment of effects of genetic manipulations in mice taste, we have recorded the whole-nerve integrated responses to a wide array of taste stimuli in the Chorda Tympani (CT) and glossopharyngeal (NG) nerves, the two major taste nerves from the tongue.
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sense of taste in a new world monkey the common marmoset recordings from the Chorda Tympani and glossopharyngeal nerves
Journal of Neurophysiology, 2002Co-Authors: Vicktoria Danilova, Thomas W. Roberts, Yuri Danilov, Jean Marie Tinti, Claude Nofre, Göran HellekantAbstract:Whole nerve, as well as single fiber, responses in the Chorda Tympani proper (CT) and glossopharyngeal (NG) nerves of common marmosets were recorded during taste stimulation with three salts, four ...
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behavioral and single Chorda Tympani taste fiber responses in the common marmoset callithrix jacchus jacchus
Annals of the New York Academy of Sciences, 1998Co-Authors: Vicktoria Danilova, Göran Hellekant, Thomas W. Roberts, Jean Marie Tinti, Claude NofreAbstract:: Gustatory responses of the common marmoset were studied using single fiber recordings from Chorda Tympani (CT) nerve and two bottle preference (TBP) tests. Hierarchical cluster analysis of 43 fibers' response profiles revealed 3 major clusters of fibers characterized by predominant sensitivity to sweeteners (S cluster), bitter compounds (Q cluster) or acids (H cluster). NaCl as well as LiCl did not stimulate CT taste fibers. The TBP tests showed relationship between a compound's ability to stimulate the taste fibers and the animals' consumption. Activity in the S cluster was associated with preference, while the activity in the Q cluster was associated with rejection. Marmosets neither preferred nor rejected sweeteners which did not stimulate any CT fibers.
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Primate Sense of Taste: Behavioral and Single Chorda Tympani and Glossopharyngeal Nerve Fiber Recordings in the Rhesus Monkey, Macaca mulatta
Journal of neurophysiology, 1997Co-Authors: Göran Hellekant, Vicktoria Danilova, Yuzo NinomiyaAbstract:Hellekant, Goran, Vicktoria Danilova, and Yuzo Ninomiya. Primate sense of taste: behavioral and single Chorda Tympani and glossopharyngeal nerve fiber recordings in the rhesus monkey, Macaca mulatt...
Göran Hellekant - One of the best experts on this subject based on the ideXlab platform.
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Responses of single Chorda Tympani taste fibers of the calf (Bos taurus).
Chemical senses, 2010Co-Authors: Göran Hellekant, Thomas W. Roberts, Donald Elmer, Tiffany Cragin, Vicktoria DanilovaAbstract: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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comparison of the responses of the Chorda Tympani and glossopharyngeal nerves to taste stimuli in c57bl 6j mice
BMC Neuroscience, 2003Co-Authors: Vicktoria Danilova, Göran HellekantAbstract:Background Recent progress in discernment of molecular pathways of taste transduction underscores the need for comprehensive phenotypic information for the understanding of the influence of genetic factors in taste. To obtain information that can be used as a base line for assessment of effects of genetic manipulations in mice taste, we have recorded the whole-nerve integrated responses to a wide array of taste stimuli in the Chorda Tympani (CT) and glossopharyngeal (NG) nerves, the two major taste nerves from the tongue.
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sense of taste in a new world monkey the common marmoset recordings from the Chorda Tympani and glossopharyngeal nerves
Journal of Neurophysiology, 2002Co-Authors: Vicktoria Danilova, Thomas W. Roberts, Yuri Danilov, Jean Marie Tinti, Claude Nofre, Göran HellekantAbstract:Whole nerve, as well as single fiber, responses in the Chorda Tympani proper (CT) and glossopharyngeal (NG) nerves of common marmosets were recorded during taste stimulation with three salts, four ...
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behavioral and single Chorda Tympani taste fiber responses in the common marmoset callithrix jacchus jacchus
Annals of the New York Academy of Sciences, 1998Co-Authors: Vicktoria Danilova, Göran Hellekant, Thomas W. Roberts, Jean Marie Tinti, Claude NofreAbstract:: Gustatory responses of the common marmoset were studied using single fiber recordings from Chorda Tympani (CT) nerve and two bottle preference (TBP) tests. Hierarchical cluster analysis of 43 fibers' response profiles revealed 3 major clusters of fibers characterized by predominant sensitivity to sweeteners (S cluster), bitter compounds (Q cluster) or acids (H cluster). NaCl as well as LiCl did not stimulate CT taste fibers. The TBP tests showed relationship between a compound's ability to stimulate the taste fibers and the animals' consumption. Activity in the S cluster was associated with preference, while the activity in the Q cluster was associated with rejection. Marmosets neither preferred nor rejected sweeteners which did not stimulate any CT fibers.
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Primate Sense of Taste: Behavioral and Single Chorda Tympani and Glossopharyngeal Nerve Fiber Recordings in the Rhesus Monkey, Macaca mulatta
Journal of neurophysiology, 1997Co-Authors: Göran Hellekant, Vicktoria Danilova, Yuzo NinomiyaAbstract:Hellekant, Goran, Vicktoria Danilova, and Yuzo Ninomiya. Primate sense of taste: behavioral and single Chorda Tympani and glossopharyngeal nerve fiber recordings in the rhesus monkey, Macaca mulatt...
Ilene L Bernstein - One of the best experts on this subject based on the ideXlab platform.
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neonatal Chorda Tympani transection permanently disrupts fungiform taste bud and papilla structure in the rat
Physiology & Behavior, 2000Co-Authors: Suzanne I Sollars, Ilene L BernsteinAbstract:Abstract The present report examined the morphology of fungiform papillae in adult rats that received bilateral Chorda Tympani transection at 10 days of age. Tongue tissue was examined using surface-structure analysis. Counts were made of fungiform papillae with a pore, fungiform papillae with no pore and fungiform papillae with a keratinized conical surface; a feature referred to as “filiform-like.” Neonatal Chorda Tympani nerve transection resulted not only in a loss of taste buds but also in a permanent loss in numbers of fungiform papillae. Compared with an average of 152 fungiform papillae in sham-operated control rats, there was an average of only 54 fungiform papillae after neonatal Chorda Tympani transection. Nearly 80% of these fungiform papillae in neonatal Chorda Tympani transected rats were filiform-like. No filiform-like papillae were noted in sham-operated rats. These results suggest that the Chorda Tympani nerve is necessary during an early postnatal period of development to maintain normal fungiform papillae morphology.
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sodium appetite in the sham drinking rat after Chorda Tympani nerve transection
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 1996Co-Authors: S P Frankmann, Suzanne I Sollars, Ilene L BernsteinAbstract:Sodium depletion in the neurologically intact rat (Intact) produces a prompt and robust intake of NaCl. After Chorda Tympani nerve transection (CTX), there is a longer latency and a reduced intake of NaCl. The CTX rat depends on remaining gustatory and postingestive information to direct NaCl intake. In the present study, the effect of the removal of the postingestive signals of ingested NaCl (by means of a chronic gastric fistula) on the NaCl intakes and licking patterns of Intact and CTX rats was studied. When the gastric fistula was open (Sham), ingested NaCl did not pass beyond the stomach, thus negative postingestive stimulation was absent. After overnight sodium depletion, when postingestive stimulation was present (i.e., gastric fistula closed; Real), the CTX group drank significantly less 0.3 M NaCl than the Intact group over the 2-h test [11.7 +/- 1.6 (CTX) vs. 15.3 +/- 2.8 (Intact) ml]. In contrast, when postingestive signals were absent (i.e., Sham) the Intact group ingested 52.5 +/- 4.4 ml, whereas the CTX group had ingested only 12.4 +/- 3.1 ml of 0.3 M NaCl. Lickometer data analysis revealed that even during the first minute of the test the CTX/Real group generated significantly fewer licks than any of the other groups. Thus, although the CTX group was sensitive to inhibitory postingestive signals in the early portion of the appetite test, the absence of these signals did not release the robust and sustained intake of NaCl characteristic of the Intact group. These results suggest that information provided by the Chorda Tympani nerve is critically important to the strong motivational properties of NaCl after sodium depletion.