Department of Cell and Systems Physiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, 807-8555, Japan.
Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, 112, Taiwan, Republic of China.
Pflugers Arch. 2018 Jan;470(1):29-38. doi: 10.1007/s00424-017-2047-2. Epub 2017 Jul 31.
Adrenal medullary chromaffin cells in mammals are innervated by sympathetic preganglionic nerve fibers, as are sympathetic ganglion neurons. Acetylcholine in the ganglion neurons is well established as mediating fast and slow excitatory postsynaptic potentials through nicotinic and muscarinic acetylcholine receptors (AChRs), respectively. The role of muscarinic AChRs during neuronal transmission in chromaffin cells varies among different mammals. Furthermore, the ion channel mechanisms associated with the muscarinic AChR-mediated increase in excitability of chromaffin cells are complicated and different from the excitation of ganglion neurons, which has been ascribed to the inhibition of M-type K channels. In this review, we focus on muscarinic receptor-mediated excitation in rodent and guinea pig chromaffin cells, in particular, on the role of muscarinic receptors in neuronal transmission, the muscarinic receptor subtypes involved in excitation and secretion, and the muscarinic regulation of ion channels including TWIK-related acid-sensitive K channels. Finally, we discuss prospectively the future of muscarinic receptor research in adrenal chromaffin cells.
哺乳动物的肾上腺髓质嗜铬细胞和交感节前神经纤维一样，都受到交感神经节神经元的支配。神经节神经元中的乙酰胆碱被认为分别通过烟碱型乙酰胆碱受体 (nAChRs) 和毒蕈碱型乙酰胆碱受体 (mAChRs) 介导快速和慢速兴奋性突触后电位。mAChRs 在不同哺乳动物的嗜铬细胞神经元传递中的作用存在差异。此外，与 mAChR 介导的嗜铬细胞兴奋性增加相关的离子通道机制复杂且不同于神经节神经元的兴奋，其归因于 M 型钾通道的抑制。在这篇综述中，我们重点关注啮齿动物和豚鼠嗜铬细胞中 mAChR 介导的兴奋，特别是 mAChR 在神经元传递中的作用、参与兴奋和分泌的 mAChR 亚型，以及 mAChR 对 TWIK 相关酸敏感钾通道等离子通道的调节。最后，我们前瞻性地讨论了肾上腺嗜铬细胞中 mAChR 研究的未来。
