Finley J C, Erickson J T, Katz D M
Department of Medicine, University Hospitals of Cleveland, OH 44106, USA.
Neuroscience. 1995 Oct;68(3):937-42. doi: 10.1016/0306-4522(95)00176-j.
The present study examined expression and plasticity of the neuropeptide, galanin, in carotid body afferent neurons in the petrosal ganglion of the adult rat. The pattern of galanin expression was compared with that of tyrosine hydroxylase, a selective marker of dopaminergic carotid body afferents in the petrosal ganglion. In normal animals, only 3% of tyrosine hydroxylase-containing petrosal ganglion neurons co-expressed galanin. Retrograde labeling studies, in which FluoroGold was injected into the vascularly isolated carotid body, demonstrated that all tyrosine hydroxylase-positive-galanin-positive cells in the petrosal ganglion project to this target. In addition, however, we unexpectedly found that galanin expression was markedly increased in the petrosal ganglion following FluoroGold injection into the carotid body. On the other hand, tyrosine hydroxylase expression was unchanged, indicating that monoaminergic and peptidergic traits can be differentially regulated in these cells. In summary, these data demonstrate that monoaminergic chemoafferent neurons can co-express a peptidergic trait, similar to catecholaminergic neurons within the central and autonomic nervous systems, and that these cells retain the potential for phenotypic plasticity in adulthood.
本研究检测了成年大鼠岩神经节中颈动脉体传入神经元内神经肽甘丙肽的表达及可塑性。将甘丙肽的表达模式与酪氨酸羟化酶（岩神经节中多巴胺能颈动脉体传入神经的一种选择性标志物）的表达模式进行了比较。在正常动物中，仅3%含酪氨酸羟化酶的岩神经节神经元共表达甘丙肽。逆行标记研究中，将荧光金注入血管分离的颈动脉体，结果显示岩神经节中所有酪氨酸羟化酶阳性且甘丙肽阳性的细胞均投射至该靶点。然而，除此之外，我们意外发现，将荧光金注入颈动脉体后，岩神经节中甘丙肽的表达显著增加。另一方面，酪氨酸羟化酶的表达未发生变化，这表明这些细胞中的单胺能和肽能特性可受到不同调控。总之，这些数据表明，单胺能化学传入神经元可共表达肽能特性，这与中枢和自主神经系统内的儿茶酚胺能神经元类似，且这些细胞在成年期仍具有表型可塑性的潜力。
