Matsui Hitoshi, Noguchi Tomohiro, Takakusaki Kaoru, Kashiwayanagi Makoto
Department of Sensory Physiology, Asahikawa Medical University.
Biol Pharm Bull. 2014;37(12):1907-12. doi: 10.1248/bpb.b14-00413.
TRPV2, a member of the transient receptor potential family, has been isolated as a capsaicin-receptor homolog and is thought to respond to noxious heat. Here we show that TRPV2 mRNA is predominantly expressed in the subpopulation of olfactory sensory neurons (OSNs). We carried out histochemical analyses of TRPV2 and insulin-like growth factor-I receptor (IGF-IR) using in situ hybridization and immunofluorescence in the adult olfactory system. In olfactory mucosa, intensive TRPV2 immunostaining was observed at the olfactory axon bundles but not at the soma. TRPV2-positive labeling was preferentially found in the olfactory nerve layer in the olfactory bulb (OB). Furthermore, we demonstrated that a positive signal for IGF-IR mRNA was detected in OSNs expressing TRPV2 mRNA. In embryonic stages, TRPV2 immunoreactivity was observed on axon bundles of developing OSNs in the nasal region starting from 12.5 d of gestation and through fetal development. Observations in this study suggest that TRPV2 coupled with IGF-IR localizes to growing olfactory axons in the OSNs.
瞬时受体电位家族成员TRPV2已作为辣椒素受体同系物被分离出来，并被认为对有害热有反应。在这里，我们表明TRPV2 mRNA主要在嗅觉感觉神经元（OSN）亚群中表达。我们在成年嗅觉系统中使用原位杂交和免疫荧光对TRPV2和胰岛素样生长因子-I受体（IGF-IR）进行了组织化学分析。在嗅觉黏膜中，在嗅觉轴突束处观察到强烈的TRPV2免疫染色，但在胞体处未观察到。TRPV2阳性标记优先出现在嗅球（OB）的嗅神经层中。此外，我们证明在表达TRPV2 mRNA的OSN中检测到IGF-IR mRNA的阳性信号。在胚胎阶段，从妊娠12.5天开始直至胎儿发育，在鼻区发育中的OSN的轴突束上观察到TRPV2免疫反应性。本研究中的观察结果表明，与IGF-IR偶联的TRPV2定位于OSN中正在生长的嗅觉轴突上。
