Mynlieff M, Curella P, Zahniser N R, Gerhardt G A, Seiger A, Dunwiddie T V
Department of Physiology, Colorado State University, Fort Collins 80523.
Synapse. 1990;6(2):113-20. doi: 10.1002/syn.890060202.
Hippocampal tissue transplanted into the anterior chamber of the eye offers a unique system in which development can be studied in the absence of the noradrenergic innervation. This system was used to determine the extent to which noradrenergic innervation regulates the development of adrenergic receptors. In addition to examining single denervated transplants, transplants grown with innervation from the superior cervical ganglia of the host rat or from locus coeruleus cotransplants were also examined to determine whether the source of norepinephrine and extent of innervation in oculo regulate the development and density of adrenergic receptors. In vitro autoradiographic analysis of ligand binding to both alpha 1- and beta-adrenergic receptors with 125I-BE 2254 and 125I-pindolol, respectively, was used to characterize adrenergic receptors in the intraocular transplants. Quantitative analysis of the receptors showed an up-regulation of both alpha 1- and beta-adrenergic receptors in tissue grown in the absence of norepinephrine, but in general there was not a high degree of correlation between norepinephrine content and receptor density. Although high-performance liquid chromatography (HPLC) analysis of catecholamines revealed higher than normal amounts of norepinephrine in hippocampal transplants innervated by the superior cervical ganglia or a locus coeruleus cotransplant, the density of alpha 1 and beta receptors was quite comparable with values found in the literature for normal adult hippocampus. These results suggest that the relationship between receptor number and density of innervation may differ significantly from what is observed in response to pharmacological manipulation of norepinephrine systems in the adult brain.
移植到眼前房的海马组织提供了一个独特的系统，在该系统中可以在没有去甲肾上腺素能神经支配的情况下研究发育过程。这个系统被用来确定去甲肾上腺素能神经支配在多大程度上调节肾上腺素能受体的发育。除了检查单个去神经支配的移植组织外，还检查了与宿主大鼠颈上神经节或蓝斑共移植的神经支配一起生长的移植组织，以确定眼内去甲肾上腺素的来源和神经支配程度是否调节肾上腺素能受体的发育和密度。分别用125I-BE 2254和125I-吲哚洛尔对α1和β肾上腺素能受体进行配体结合的体外放射自显影分析，以表征眼内移植组织中的肾上腺素能受体。对受体的定量分析表明，在没有去甲肾上腺素的情况下生长的组织中，α1和β肾上腺素能受体均上调，但一般而言，去甲肾上腺素含量与受体密度之间没有高度相关性。尽管高效液相色谱（HPLC）对儿茶酚胺的分析显示，由颈上神经节或蓝斑共移植支配的海马移植组织中去甲肾上腺素含量高于正常水平，但α1和β受体的密度与文献中正常成年海马的值相当。这些结果表明，受体数量与神经支配密度之间的关系可能与在成年大脑中对去甲肾上腺素系统进行药理学操作时所观察到的情况有显著差异。
