Suzuki Yuko, Mizoguchi Itaru, Uchida Nobuhiko
Division of Histology, Department of Oral Growth and Development, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Japan.
Arch Histol Cytol. 2007 Jul;70(2):117-26. doi: 10.1679/aohc.70.117.
Neurotrophic factors are thought to function in the survival and maintenance of the taste buds and nerve fibers innervating them. Laser capture microdissection (LCM) coupled with the reverse transcription polymerase chain reaction (RT-PCR) was performed to detect the mRNA of neurotrophic factors and their receptors in the taste buds of adult mouse circumvallate papillae. Results showed mRNAs of the ciliary neurotrophic factor (CNTF), its receptor (CNTFR), glial cell line-derived neurotrophic factor (GDNF), GDNF family receptors alpha-1 (GFRalpha-1), GFRalpha-2, and RET tyrosine kinase receptor (RET), neurotrophin (NT)3, NT4/5, tyrosine kinase (Trk) C, nerve growth factor (NGF), and TrkA were expressed in the isolated taste buds. Among these neurotrophic factors, GDNF, GFRalpha-1, GFRalpha-2, NT3, NT4/5, NGF, and TrkA were previously found in the taste buds immunohistochemically and were detected at the mRNA level in the present study. The present immunohistochemical study revealed that CNTF, CNTFR, and the RET tyrosine kinase receptor, which binds GDNF family/ receptor complexes, were also expressed in the taste buds. However, by in situ hybridization, mRNAs of CNTF and RET were not detected in the taste buds from adult mice although they were found in those from early postnatal mice. CNTFR mRNA did not show any specific pattern in the taste buds. Moreover, mRNA expressions of NT4/5 and TrkC was re-examined by in situ hybridization; however no specific pattern was found for them in the taste buds. In summary, LCM is a useful tool for the detection of a relatively small amount of mRNA, such as that of neurotrophic factors and receptors in the taste buds.
神经营养因子被认为在味蕾及其支配神经纤维的存活和维持中发挥作用。采用激光捕获显微切割技术（LCM）结合逆转录聚合酶链反应（RT-PCR），检测成年小鼠轮廓乳头味蕾中神经营养因子及其受体的mRNA。结果显示，睫状神经营养因子（CNTF）、其受体（CNTFR）、胶质细胞源性神经营养因子（GDNF）、GDNF家族受体α-1（GFRα-1）、GFRα-2、RET酪氨酸激酶受体（RET）、神经营养因子（NT）3、NT4/5、酪氨酸激酶（Trk）C、神经生长因子（NGF）和TrkA的mRNA在分离的味蕾中表达。在这些神经营养因子中，GDNF、GFRα-1、GFRα-2、NT3、NT4/5、NGF和TrkA先前已通过免疫组织化学在味蕾中发现，且在本研究中也在mRNA水平检测到。本免疫组织化学研究表明，CNTF、CNTFR以及与GDNF家族/受体复合物结合的RET酪氨酸激酶受体也在味蕾中表达。然而，通过原位杂交，虽然在出生后早期小鼠的味蕾中发现了CNTF和RET的mRNA，但在成年小鼠的味蕾中未检测到。CNTFR mRNA在味蕾中未显示任何特定模式。此外，通过原位杂交重新检测了NT4/5和TrkC的mRNA表达；然而，在味蕾中未发现它们的特定模式。总之，LCM是检测相对少量mRNA（如味蕾中神经营养因子和受体的mRNA）的有用工具。
