TY - JOUR
T1 - Up-regulation of activated macrophages in response to degeneration in the taste system
T2 - Effects of dietary sodium restriction
AU - McCluskey, Lynnette Phillips
PY - 2004/11/1
Y1 - 2004/11/1
N2 - Dietary sodium restriction combined with unilateral chorda tympani nerve section leads to a rapid and specific decrease in neurophysiological taste responses to sodium in the contralateral, intact chorda tympani (Hill and Phillips [1994] J. Neurosci. 14:2904-2910). Previous work demonstrated that dietary sodium restriction may induce these early functional deficits by inhibiting immune activity after denervation (Phillips and Hill [1996] Am. J. Physiol. 271:R857-R862). However, little is known about the leukocyte response to denervation of taste buds in fungiform papillae. In the current study, it was hypothesized that T cells and macrophages are increased in the tongue after unilateral denervation in control-fed but not sodium-restricted animals. Adult, specified pathogen-free rats received unilateral chorda tympani nerve section or sham section followed by dietary sodium restriction or maintenance on control diet. At day 1, 2, 5, 7, or 50 postsectioning, immunostaining was used to detect the percentage of staining for activated macrophages, the number of αβ T cells, and the number of δγ epithelial T cells in the tongue. The number of lingual T cells did not significantly differ between treatment groups following denervation. However, there was a dramatic bilateral increase in ED1+ staining for activated macrophages in control-fed rats that peaked at day 2 postsectioning. In contrast, sodium-restricted rats did not show an increase in activated macrophages above baseline at any time postsectioning. Further analysis of extralingual macrophages indicated that the deficit in immune activity in sodium-restricted rats is localized to the tongue and is not widespread. A model for immune modulation of taste receptor cell function is proposed based on these novel findings.
AB - Dietary sodium restriction combined with unilateral chorda tympani nerve section leads to a rapid and specific decrease in neurophysiological taste responses to sodium in the contralateral, intact chorda tympani (Hill and Phillips [1994] J. Neurosci. 14:2904-2910). Previous work demonstrated that dietary sodium restriction may induce these early functional deficits by inhibiting immune activity after denervation (Phillips and Hill [1996] Am. J. Physiol. 271:R857-R862). However, little is known about the leukocyte response to denervation of taste buds in fungiform papillae. In the current study, it was hypothesized that T cells and macrophages are increased in the tongue after unilateral denervation in control-fed but not sodium-restricted animals. Adult, specified pathogen-free rats received unilateral chorda tympani nerve section or sham section followed by dietary sodium restriction or maintenance on control diet. At day 1, 2, 5, 7, or 50 postsectioning, immunostaining was used to detect the percentage of staining for activated macrophages, the number of αβ T cells, and the number of δγ epithelial T cells in the tongue. The number of lingual T cells did not significantly differ between treatment groups following denervation. However, there was a dramatic bilateral increase in ED1+ staining for activated macrophages in control-fed rats that peaked at day 2 postsectioning. In contrast, sodium-restricted rats did not show an increase in activated macrophages above baseline at any time postsectioning. Further analysis of extralingual macrophages indicated that the deficit in immune activity in sodium-restricted rats is localized to the tongue and is not widespread. A model for immune modulation of taste receptor cell function is proposed based on these novel findings.
KW - Chorda tympani nerve
KW - Degeneration
KW - Macrophage
KW - Neuroimmune interactions
KW - T cell
KW - Taste receptor cells
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U2 - 10.1002/cne.20307
DO - 10.1002/cne.20307
M3 - Article
C2 - 15389612
AN - SCOPUS:4644323791
SN - 0021-9967
VL - 479
SP - 43
EP - 55
JO - Journal of Comparative Neurology
JF - Journal of Comparative Neurology
IS - 1
ER -