Burette A, Jalenques I, Romand R
Laboratoire de Neurobiologie, Université, Blaise Pascal, Aubière, France.
Brain Res. 1997 Nov 21;776(1-2):10-23. doi: 10.1016/s0006-8993(97)00934-7.
By virtue of its known segregated distribution of cell types, their known neurotransmitters and neurophysiologic properties, the cochlear nucleus is an excellent model and provides the opportunity to study the relation between neurotrophins and their receptors along with the functional properties of the adult cochlear nucleus. To investigate the potential role of neurotrophins in the mature cochlear nucleus, we determined the expression of the three major neurotrophin tyrosine kinase receptors (Trk) in the adult rat ventral cochlear nucleus, as revealed by antibodies against the full-Trk proteins. A qualitative and a cartographic analysis showed a widespread distribution of the three Trk receptors throughout the nucleus. Immunostaining was mainly restricted to neurons as shown by the lack of double immunostaining with specific markers for glial cells. However, we observed variability in immunostaining for given receptors. Three classes of cells were distinguished by their specificity for Trk receptors. The first one was a cell population that stained for TrkA or TrkB. This population characterizes the majority of small and small round neurons and fusiform cells. The second group consists of TrkC-immunolabeled cells and comprises the majority of spherical, globular, granule and small multipolar cells. The third group consists of cells that seem to be immunopositive for all three Trk receptors. This group includes in part multipolar, giant and octopus cells. A possible correlation between Trk expression and cell functional properties is suggested: TrkA- and TrkB-immunoreactive cells could include inhibitory neurons while cells stained for TrkC could include excitatory neurons. The abundant and widespread neuronal distribution of signal-transducing forms of TrkA, TrkB and TrkC predicts that their cognate ligands may exert significant effects on a large proportion of neurons within the mature ventral cochlear nucleus.
由于其已知的细胞类型分离分布、已知的神经递质和神经生理特性，耳蜗核是一个优秀的模型，为研究神经营养因子及其受体之间的关系以及成年耳蜗核的功能特性提供了机会。为了研究神经营养因子在成熟耳蜗核中的潜在作用，我们通过针对完整Trk蛋白的抗体，确定了成年大鼠腹侧耳蜗核中三种主要神经营养因子酪氨酸激酶受体（Trk）的表达。定性和图谱分析表明，三种Trk受体在整个核中广泛分布。免疫染色主要局限于神经元，这通过与神经胶质细胞特异性标记物的双重免疫染色缺失得以证明。然而，我们观察到给定受体免疫染色的变异性。根据它们对Trk受体的特异性区分出三类细胞。第一类是对TrkA或TrkB染色的细胞群体。该群体表征了大多数小的和小圆形神经元以及梭形细胞。第二类由TrkC免疫标记的细胞组成，包括大多数球形、球状、颗粒状和小多极细胞。第三类由似乎对所有三种Trk受体均呈免疫阳性的细胞组成。该群体部分包括多极、巨型和章鱼状细胞。提示Trk表达与细胞功能特性之间可能存在相关性：TrkA和TrkB免疫反应性细胞可能包括抑制性神经元，而TrkC染色的细胞可能包括兴奋性神经元。TrkA、TrkB和TrkC信号转导形式丰富且广泛的神经元分布预示着它们的同源配体可能对成熟腹侧耳蜗核内的大部分神经元产生显著影响。
