Original Research ARTICLE
Distribution of alpha7 Nicotinic Acetylcholine Receptor Subunit mRNA in the Developing Mouse
- 1University of California, Irvine, United States
- 2Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, United States
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 cells in neuronal tissue with limited effects in non-neural tissues.
Keywords: Cortex, Hippocampus, Spinal Cord, Enteric Nervous System, Dorsal root ganglia (DRG), Adrenal Medulla, Kidney, Nicotine
Received: 15 Apr 2019;
Accepted: 12 Jul 2019.
Edited by:Francesco Fornai, University of Pisa, Italy
Reviewed by:Rita Machaalani, Sydney Medical School, University of Sydney, Australia
Jerry Stitzel, University of Colorado Boulder, United States
Copyright: © 2019 Broide, Winzer-Serhan, Leslie and Chen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Ursula H. Winzer-Serhan, Texas A&M Health Science Center, Neuroscience and Experimental Therapeutics, Bryan, 77807, Texas, United States, UWSerhan@medicine.tamhsc.edu