Tyrrell S, Landis S C
Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
J Neurosci. 1994 Jul;14(7):4529-47. doi: 10.1523/JNEUROSCI.14-07-04529.1994.
Mature sympathetic neurons contain one or more neuropeptides in addition to a classical neurotransmitter. We compared the development of two peptides, neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP), in rat superior cervical (SCG) and stellate ganglia. NPY immunoreactivity (-IR) was first detected at embryonic day (E) 12.5. It was of similar immunofluorescence intensity in almost all tyrosine hydroxylase (TH)-IR cells. In contrast, VIP-IR, of variable fluorescence intensity, appeared at E14.5 in a subset of TH-IR cells in the stellate ganglion but not in SCG. Both peptides were present in bromodeoxyuridine-labeled neuronal precursors as well as neurons. The intensity of NPY immunofluorescence increased until E16.5. Subsequently, while it continued to increase in some neurons, the intensity decreased in others so that at birth approximately 55% of SCG and stellate neurons were NPY-IR. Developmental changes in NPY concentration, determined by radioimmunoassay, were similar in both ganglia, increasing between E14.5 and E16.5 and then decreasing 60% between E16.5 and birth. VIP expression differed from that of NPY. The proportion of VIP-IR cells began to decrease the day after VIP-IR was first detected. Although VIP-IR was present in one-third of E14.5 TH-IR stellate cells, at birth only 2% were VIP-IR. VIP-IR, measured by radioimmunoassay, was uniformly severalfold more concentrated in the stellate than SCG, and its concentration decreased throughout embryonic development, 40% between E14.5 and E16.5 and 95% by birth. In situ hybridization revealed detectable mRNA for both NPY and VIP at E14.5 in stellate ganglion and mRNA for NPY, but not VIP, in SCG. Initially, ganglionic neuropeptide mRNA appeared uniformly distributed but became heterogeneous. Our data indicate that features of the diverse peptidergic phenotypes expressed by sympathetic neurons are present when peptides are first detected while others arise subsequently. The final acquisition of peptidergic phenotypic diversity is complex, entailing both early induction in many cells and subsequent restriction to specific subpopulations.
成熟的交感神经元除了含有一种经典神经递质外，还含有一种或多种神经肽。我们比较了大鼠颈上神经节（SCG）和星状神经节中两种肽，即神经肽Y（NPY）和血管活性肠肽（VIP）的发育情况。NPY免疫反应性（-IR）在胚胎第12.5天首次被检测到。在几乎所有酪氨酸羟化酶（TH）-IR细胞中，其免疫荧光强度相似。相比之下，荧光强度可变的VIP-IR在胚胎第14.5天出现在星状神经节中TH-IR细胞的一个亚群中，而在颈上神经节中未出现。两种肽都存在于溴脱氧尿苷标记的神经元前体细胞以及神经元中。NPY免疫荧光强度一直增加到胚胎第16.5天。随后，虽然在一些神经元中它继续增加，但在另一些神经元中强度下降，因此在出生时，约55%的颈上神经节和星状神经节神经元是NPY-IR。通过放射免疫测定确定的NPY浓度的发育变化在两个神经节中相似，在胚胎第14.5天至第16.5天之间增加，然后在胚胎第16.5天至出生之间下降60%。VIP的表达与NPY不同。VIP-IR细胞的比例在首次检测到VIP-IR后的第二天开始下降。虽然在胚胎第14.5天三分之一的TH-IR星状细胞中存在VIP-IR，但在出生时只有2%是VIP-IR。通过放射免疫测定，VIP-IR在星状神经节中的浓度始终比颈上神经节高三倍多，并且其浓度在整个胚胎发育过程中下降，在胚胎第14.5天至第16.5天之间下降40%，到出生时下降95%。原位杂交显示，在胚胎第14.5天，星状神经节中可检测到NPY和VIP的mRNA，而颈上神经节中可检测到NPY的mRNA，但未检测到VIP的mRNA。最初，神经节神经肽mRNA呈均匀分布，但后来变得不均匀。我们的数据表明，交感神经元表达的多种肽能表型的特征在首次检测到肽时就已存在，而其他特征随后才出现。肽能表型多样性的最终获得是复杂的，需要在许多细胞中早期诱导，随后限制在特定亚群中。
