P2X2- and P2X3-Positive Fibers in Fungiform Papillae Originate From the Chorda Tympani but Not the Trigeminal Nerve in Rats and Mice
P2X2- and P2X3-Positive Fibers in Fungiform Papillae Originate From the Chorda Tympani but Not the Trigeminal Nerve in Rats and Mice
复制标题
DOI：
10.1002/cne.22000
复制
发表时间：
2009-05-10
影响因子：
2.5
通讯作者：
Shimada, Shoichi
中科院分区：
文献类型：
--
作者：
Ishida, Yusuke;Ugawa, Shinya;Shimada, Shoichi
2型和3型离子型嘌呤能受体（P2 X受体）对味觉至关重要，但这些受体在膝状神经节（GG）中的分布及其在舌乳头中的共定位仍不清楚。本研究采用原位杂交和免疫组织化学方法研究了P2 X（2）和P2 X（3）受体在大鼠和小鼠的GG和菌状乳头中的表达和共定位。在这两个物种中，P2 X（2）转录本和免疫反应在大约50-60%的GG神经元胞体中检测到，而P2 X的转录本和免疫反应在几乎所有的神经元中观察到。在每个菌状乳头，两种受体的免疫反应主要是共定位，并被认为是在神经纤维和它们的束集中在味蕾。因为众所周知P2 X受体不仅参与味觉而且参与伤害感受，所以我们通过切割两种动物中的CT来确定表达是否起源于鼓索神经（CT，味觉）或三叉神经（躯体感觉）。真菌状乳头内的P2 X（2）和P2 X（3）免疫反应性在切断后消失，而瞬时感受器电位V1（体感神经纤维的标记）的神经纤维免疫反应性保持不变，表明大多数具有P2 X（2）和P2 X（3）受体的真菌状乳头神经纤维来自CT。综上所述，这些发现表明菌状乳头中的大多数P2 X（2）和P2 X（3）受体用于味觉而不是躯体感觉。J. Comp.神经元514：131-144，2009. (C)2009威利-利斯公司
The subtype 2 and subtype 3 ionotropic purinergic receptors (P2X receptors) are crucial for gustation, but the distribution of these receptors in the geniculate ganglion (GG) and their colocalization in tongue papillae remain unknown. Here we investigated the expression and colocalization of P2X(2) and P2X(3) receptors in the GG and fungiform papillae in rats and mice by using in situ hybridization and immunohistochemistry. In both species, P2X(2) transcripts and immunoreactivity were detected in approximately 50-60% of GG neuronal somata, whereas those of P2X, were observed in almost all neurons. In each fungiform papilla, immunoreactivity for both receptors was mostly colocalized and was seen in nerve fibers and their bundles concentrated in the taste buds. Because it is well known that the P2X receptors are involved in not only taste but also nociception, we determined whether the expression originated from the chorda tympani nerve (CT, gustatory) or trigerninal nerve (somatosensory) by cutting the CT in both animals. Most P2X(2) and P2X(3) immunoreactivity in the fungiform papillae was abolished after transection, although the nerve fiber immunoreactivity of transient receptor potential V1 (a marker of somatosensory nerve fibers) remained unchanged, Indicating that most fungiform papillae nerve fibers with P2X(2) and P2X(3) receptors were derived from CT. Taken together, these findings suggest that most P2X(2) and P2X(3) receptors in fungiform papillae are used for gustation rather than somatosensation. J. Comp. Neurol. 514:131-144, 2009. (C) 2009 Wiley-Liss, Inc.