Lipopolysaccharide-induced up-regulation of activated macrophages in the degenerating taste system

Cavallin, Melissa Ann; McCluskey, Lynnette Phillips

doi:10.1002/jnr.20438

Cited by 19 publications

(52 citation statements)

References 44 publications

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“…Previous research demonstrated that sodium restriction leads to an attenuation of chorda tympani nerve responses to sodium salts when combined with nerve or lingual epithelial injury, also resulting in an attenuated lingual macrophage response to injury (6,7,22,32,33,39). Stimulating the immune response with LPS injections eliminates these differences (6,39).…”

Section: Discussionmentioning

confidence: 95%

“…Thus, aldosterone suppressed the bilateral macrophage response to neural injury. Control staining, in which the primary antibody was omitted or an isotype-matched irrelevant antibody was substituted (not shown), showed minimal nonspecific immunoreactivity (6,32).…”

Section: Neurophysiologymentioning

confidence: 98%

“…Rats were euthanized with pentobarbital sodium (80 mg/kg ip) at day 2 following surgery, at the peak of the macrophage response to CTX (32). The anterior tongue was removed rapidly, frozen and cryosectioned at 8 m, as described previously (6,32). Approximately 300 sections were collected from the fungiform papillae field, including ϳ150 sections from the anterior tongue, ϳ75 sections located 2 mm caudal to the anterior sections and another 75 sections after 2 mm of the tongue was skipped.…”

Section: Animalsmentioning

confidence: 99%

“…Evidence suggests this change in sodium taste responses and sensitivity to amiloride is at least partially due to a suppressed immune system in sodium-restricted rats (6,7,32,33). In rats fed a sodium-replete diet, chorda tympani nerve transection increases activated macrophages in lingual epithelium, while sodium-restricted rats fail to show the transection-induced macrophage response.…”

mentioning

confidence: 93%

“…In rats fed a sodium-replete diet, chorda tympani nerve transection increases activated macrophages in lingual epithelium, while sodium-restricted rats fail to show the transection-induced macrophage response. Upregulation of immune function with LPS eliminates both diet-related differences in sodium responsiveness and the number of activated macrophages (6,39). Thus, the functional plasticity observed with chorda tympani transection and sodium-restricted diet is associated with a suppressed immune response to nerve injury.…”

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confidence: 94%

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Attenuation of peripheral salt taste responses and local immune function contralateral to gustatory nerve injury: effects of aldosterone

Guagliardo

West

McCluskey

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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Dietary sodium restriction coupled with axotomy of the rat chorda tympani nerve (CTX) results in selectively attenuated taste responses to sodium salts in the contralateral, intact chorda tympani nerve. Converging evidence indicates that sodium deficiency also diminishes the activated macrophage response to injury on both the sectioned and contralateral, intact sides of the tongue. Because a sodium-restricted diet causes a robust increase in circulating aldosterone, we tested the hypothesis that changes in neurophysiological and immune responses contralateral to the CTX could be mimicked by aldosterone administration instead of the low-sodium diet. Taste responses in rats with CTX and supplemental aldosterone for 4-6 days were similar to rats with CTX and dietary sodium restriction. Responses to sodium salts were as much as 50% lower compared with sham-operated and vehicle-supplemented rats. The group-related functional differences were eliminated with lingual application of amiloride, suggesting that a major transduction pathway affected was through epithelial sodium channels. Consistent with the functional results, few macrophages were observed on either side of the tongue in rats with CTX and aldosterone. In contrast, macrophages were elevated on both sides of the tongue in rats with CTX and the vehicle. These results show that sodium deficiency or administration of aldosterone suppresses the immune response to neural injury, resulting in attenuation of peripheral gustatory function. They also show a potential key link among downstream consequences of sodium imbalance, taste function, and immune activity.

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Section: Discussionmentioning

confidence: 95%

Section: Neurophysiologymentioning

confidence: 98%

Section: Animalsmentioning

confidence: 99%

mentioning

confidence: 93%

mentioning

confidence: 94%

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Attenuation of peripheral salt taste responses and local immune function contralateral to gustatory nerve injury: effects of aldosterone

Guagliardo

West

McCluskey

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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Fungiform taste bud degeneration in C57BL/6J mice following chorda‐lingual nerve transection

Guagliardo

Hill

2007

J of Comparative Neurology

105

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Taste buds are dependent on innervation for normal morphology and function. Fungiform taste bud degeneration after chorda tympani nerve injury has been well documented in rats, hamsters, and gerbils. The current study examines fungiform taste bud distribution and structure in adult C57BL/ 6J mice from both intact taste systems and after unilateral chorda-lingual nerve transection. Fungiform taste buds were visualized and measured with the aid of cytokeratin 8. In control mice, taste buds were smaller and more abundant on the anterior tip (<1 mm) of the tongue. By 5 days after nerve transection taste buds were smaller and fewer on the side of the tongue ipsilateral to the transection and continued to decrease in both size and number until 15 days posttransection. Degenerating fungiform taste buds were smaller due to a loss of taste bud cells rather than changes in taste bud morphology. While almost all taste buds disappeared in more posterior fungiform papillae by 15 days posttransection, the anterior tip of the tongue retained nearly half of its taste buds compared to intact mice. Surviving taste buds could not be explained by an apparent innervation from the remaining intact nerves. Contralateral effects of nerve transection were also observed; taste buds were larger due to an increase in the number of taste bud cells. These data are the first to characterize adult mouse fungiform taste buds and subsequent degeneration after unilateral nerve transection. They provide the basis for more mechanistic studies in which genetically engineered mice can be used. Indexing terms receptor cells; gustation; axotomy; cyokeratin; neurofilamentThe gustatory system provides a prime model to study neural plasticity in adult animals. Whereas in most sensory systems the innervation of the periphery by primary afferent neurons is determined early in development, the gustatory system is unique in that taste bud innervation is plastic throughout adulthood as receptor cells turn over (Farbman, 1980;Hendricks et al., 2004). Therefore, receptive fields rearrange as taste bud cells die and new cells are added. Concomitant with naturally occurring taste bud cell death, taste buds are dependent on the chorda tympani nerve to maintain their functional integrity and structure. Specifically, taste buds degenerate after nerve injury (Farbman, 1969;Hård af Segerstad et al., 1989) and reappear upon reinnervation by regenerating nerves Cain et al., 1996).While taste bud degeneration after injury to the chorda tympani nerve occurs in a variety of species, there is a substantial species-dependent diversity in the time course and degree of NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript fungiform taste bud degeneration (Farbman, 1969;Whitehead et al., 1987;Ganchrow and Ganchrow, 1989;Oakley et al., 1990Oakley et al., , 1993Cain et al., 1996). For example, over 90% of taste buds are lost by 9 days posttransection in the gerbil , while the rat and hamster lose only 28% and 26% of their taste buds after chorda tympan...

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Upregulation of intracellular adhesion molecule (ICAM)‐1 and vascular cell adhesion molecule (VCAM)‐1 after unilateral nerve injury in the peripheral taste system

Cavallin¹,

McCluskey²

2006

J of Neuroscience Research

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In the peripheral taste system, activated macrophages are recruited to both sides of the tongue after unilateral sectioning of the chorda tympani nerve (CT). Neural degeneration elicits macrophage entry in other systems by upregulating vascular adhesion molecules. We hypothesized that CT sectioning leads to a bilateral increase in intracellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 expression on lingual vessels. To test this hypothesis, rats were euthanized at time points from 6 hr to 7 days post-sectioning. Frozen sections of tongue were processed for immunohistochemical staining for ICAM-1 and VCAM-1. Tongue homogenates from additional rats were analyzed with ELISA. ICAM-1 expression increases first on the denervated side of the tongue at 24 hr post-section and then on the uninjured side at 48 hr post-section. ICAM-1 remains elevated through Day 7 post-sectioning on both sides of the tongue. Dietary sodium restriction, which prevents the macrophage response to nerve sectioning, had no effect on ICAM-1 levels. VCAM-1+ vessels are increased on the denervated side of the tongue at 24-48 hr post-section in control-fed rats. However, dietary sodium restriction prevents the increase. These results indicate that vascular adhesion molecules are differentially regulated by CT sectioning. We suggest that macrophage entry, migration, and modulation of taste function are downstream of dynamic expression of adhesion molecules.

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Lipopolysaccharide-induced up-regulation of activated macrophages in the degenerating taste system

Cited by 19 publications

References 44 publications

Attenuation of peripheral salt taste responses and local immune function contralateral to gustatory nerve injury: effects of aldosterone

Attenuation of peripheral salt taste responses and local immune function contralateral to gustatory nerve injury: effects of aldosterone

Fungiform taste bud degeneration in C57BL/6J mice following chorda‐lingual nerve transection

Upregulation of intracellular adhesion molecule (ICAM)‐1 and vascular cell adhesion molecule (VCAM)‐1 after unilateral nerve injury in the peripheral taste system

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