Stevens L M, Landis S C
Center for Neurosciences, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
Dev Biol. 1990 Jan;137(1):109-24. doi: 10.1016/0012-1606(90)90012-8.
In contrast to the majority of sympathetic neurons which are noradrenergic, the sympathetic neurons which innervate sweat glands are cholinergic. Previous studies have demonstrated that during development the sweat gland innervation initially contains catecholamines which are lost as cholinergic function appears. The neurotransmitter phenotype of sweat gland neurons further differs from the majority in that they contain vasoactive intestinal peptide (VIP) rather than neuropeptide Y (NPY). In the experiments described here, we addressed the question of whether sympathetic targets influence the neurotransmitter-related properties of the neurons which innervate them; in particular, do sweat glands play a role in reducing the expression of noradrenergic properties and inducing the expression of cholinergic properties and VIP in sympathetic neurons? This was accomplished by cotransplanting to the anterior chamber of the eye of host rats the superior cervical ganglia (SCG) which contains neurons that normally innervate targets other than the sweat glands and differentiate noradrenergically and footpad tissue from neonatal rats. Sweat glands developed in the transplanted footpad tissue and became innervated by the cotransplanted SCG neurons. The transplanted neurons and sweat gland innervation initially exhibited catecholamine histofluorescence which declined with further development in the anterior chamber. After 4 weeks, choline acetyltransferase (ChAT) and VIP immunoreactivities were evident. These observations suggest that as in the neurons which innervate the glands in situ, noradrenergic properties were suppressed and cholinergic function was induced in the neurons which innervated the glands in oculo. To distinguish a specific influence of the sweat glands on transmitter choice, SCG were also cotransplanted with the pineal gland, a normal target of the ganglion. Neurons cotransplanted with the pineal gland continued to exhibit catecholamine histofluorescence and contained NPY immunoreactivity. At least some neurons in SCG/pineal cotransplants, however, developed ChAT immunoreactivity. The target-appropriate expression of catecholamines and peptides in these experiments is consistent with the hypothesis that some transmitter properties are influenced by target tissues. The indiscriminant expression of ChAT, however, suggests that at least in oculo, additional factors can influence transmitter choice.
与大多数去甲肾上腺素能的交感神经元不同，支配汗腺的交感神经元是胆碱能的。先前的研究表明，在发育过程中，汗腺的神经支配最初含有儿茶酚胺，随着胆碱能功能的出现，这些儿茶酚胺会消失。汗腺神经元的神经递质表型与大多数神经元的进一步不同之处在于，它们含有血管活性肠肽（VIP）而非神经肽Y（NPY）。在本文所述的实验中，我们探讨了交感神经靶标是否会影响支配它们的神经元的神经递质相关特性这一问题；特别是，汗腺在减少交感神经元中去甲肾上腺素能特性的表达以及诱导胆碱能特性和VIP的表达方面是否发挥作用？这是通过将含有通常支配除汗腺以外靶标的神经元且去甲肾上腺素能分化的颈上神经节（SCG）与新生大鼠的足垫组织共同移植到宿主大鼠的眼前房来实现的。移植的足垫组织中发育出了汗腺，并由共同移植的SCG神经元进行神经支配。移植的神经元和汗腺神经支配最初表现出儿茶酚胺组织荧光，随着眼前房内的进一步发育而下降。4周后，胆碱乙酰转移酶（ChAT）和VIP免疫反应性明显。这些观察结果表明，与原位支配腺体的神经元一样，在眼内支配腺体的神经元中，去甲肾上腺素能特性受到抑制，胆碱能功能被诱导。为了区分汗腺对递质选择的特定影响，SCG也与松果体（神经节的正常靶标）共同移植。与松果体共同移植的神经元继续表现出儿茶酚胺组织荧光，并含有NPY免疫反应性。然而，SCG/松果体共同移植中的至少一些神经元出现了ChAT免疫反应性。这些实验中儿茶酚胺和肽的靶标特异性表达与某些递质特性受靶组织影响的假设一致。然而，ChAT的无差别表达表明，至少在眼内，其他因素也会影响递质选择。
