Homomeric α7 nicotinic acetylcholine receptors (nAChRs) are abundantly expressed in the central and peripheral nervous system (CNS and PNS, respectively), and spinal cord. In addition, expression and functional responses have been reported in non-neuronal tissue. In the nervous system, α7 nAChR subunit expression appears early during embryonic development and is often transiently upregulated, but little is known about their prenatal expression outside of the nervous system. For understanding potential short-term and long-term effects of gestational nicotine exposure, it is important to know the temporal and spatial expression of α7 nAChRs throughout the body. To that end, we studied the expression of α7 nAChR subunit mRNA using highly sensitive isotopic in situ hybridization in embryonic and neonatal whole-body mouse sections starting at gestational day 13. The results revealed expression of α7 mRNA as early as embryonic day 13 in the PNS, including dorsal root ganglia, parasympathetic and sympathetic ganglia, with the strongest expression in the superior cervical ganglion, and low to moderate levels were detected in brain and spinal cord, respectively, which rapidly increased in intensity with embryonic age. In addition, robust α7 mRNA expression was detected in the adrenal medulla, and low to moderate expression in selected peripheral tissues during embryonic development, potentially related to cells derived from the neural crest. Little or no mRNA expression was detected in thymus or spleen, sites of immune cell maturation. The results suggest that prenatal nicotine exposure could potentially affect the nervous system with limited effects in non-neural tissues.

中文翻译：

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在发育中的小鼠中，α7烟碱型乙酰胆碱受体亚基mRNA的分布。

同型α7烟碱乙酰胆碱受体（nAChRs）在中枢和周围神经系统（分别为CNS和PNS）和脊髓中大量表达。另外，已经报道了在非神经元组织中的表达和功能反应。在神经系统中，α7nAChR亚基的表达在胚胎发育的早期出现，并经常被短暂上调，但对它们在神经系统外的产前表达知之甚少。为了了解妊娠烟碱暴露的短期和长期影响，了解整个体内α7nAChRs的时空表达很重要。为此，我们使用高敏感度同位素原位杂交技术，从妊娠第13天开始在胚胎和新生儿全身小鼠切片中研究了α7nAChR亚基mRNA的表达。结果显示，早在PNS的胚胎第13天（包括背侧），α7mRNA的表达就开始了根神经节，副交感神经节和交感神经节在上颈神经节中表达最强，在脑和脊髓中分别检测到低至中度水平，其强度随着胚胎年龄的增加而迅速增加。此外，在肾上腺髓质中检测到强健的α7mRNA表达，在胚胎发育过程中在选定的外周组织中表达低至中等，这可能与源自神经rest的细胞有关。在胸腺或脾脏中几乎没有检测到mRNA表达，免疫细胞成熟的部位。结果表明，产前尼古丁暴露可能会影响神经系统，而对非神经组织的作用有限。