Heil Jan E, Oland Lynne A, Lohr Christian
Abteilung für Allgemeine Zoologie, TU Kaiserslautern, POB 3049, 67653 Kaiserslautern, Germany.
Eur J Neurosci. 2007 Sep;26(5):1227-41. doi: 10.1111/j.1460-9568.2007.05756.x.
In the olfactory system of the sphinx moth Manduca sexta, migration of neuropil glial cells is triggered by olfactory receptor axons and depends on intraglial Ca(2+) signaling. It is not known, however, how receptor axons and glial cells communicate and whether Ca(2+) signaling is a consequence of this communication. We studied Ca(2+) increases in glial cells in vivo and in situ, evoked by electrical stimulation of olfactory receptor axons in pupae and by odor stimulation of receptor neurons in adult moths. Axonal activity leads to Ca(2+) increases in neuropil glial cells that are blocked by nicotinic acetylcholine receptor antagonists and can be mimicked by acetylcholine and carbachol application. In addition, Ca(2+) transients were abolished by removal of external Ca(2+) and blockage of voltage-gated Ca(2+) channels. During development, acetylcholine-mediated Ca(2+) signaling could first be elicited at stage 6, the time when neuropil glial cells start to migrate. Glial migration was reduced after injection of nicotinic antagonists into pupae. The results show that Ca(2+) signaling can be induced by acetylcholine release from olfactory receptor axons, which activates nicotinic acetylcholine receptors and leads to voltage-gated Ca(2+) influx. The results further suggest that cholinergic signaling in the olfactory system is required for glial cell migration in Manduca.
在烟草天蛾的嗅觉系统中，神经毡胶质细胞的迁移由嗅觉受体轴突触发，并依赖于胶质细胞内的Ca(2+)信号传导。然而，尚不清楚受体轴突与胶质细胞如何进行通讯，以及Ca(2+)信号传导是否是这种通讯的结果。我们研究了在体内和原位条件下，蛹期对嗅觉受体轴突进行电刺激以及成虫期对受体神经元进行气味刺激时，胶质细胞内Ca(2+)的增加情况。轴突活动导致神经毡胶质细胞内Ca(2+)增加，这种增加可被烟碱型乙酰胆碱受体拮抗剂阻断，并且可通过施加乙酰胆碱和卡巴胆碱来模拟。此外，去除细胞外Ca(2+)以及阻断电压门控Ca(2+)通道可消除Ca(2+)瞬变。在发育过程中，乙酰胆碱介导的Ca(2+)信号传导最早可在第6阶段被引发，这正是神经毡胶质细胞开始迁移的时间。向蛹内注射烟碱拮抗剂后，胶质细胞迁移减少。结果表明，Ca(2+)信号传导可由嗅觉受体轴突释放的乙酰胆碱诱导，乙酰胆碱激活烟碱型乙酰胆碱受体并导致电压门控Ca(2+)内流。结果还进一步表明，烟草天蛾嗅觉系统中的胆碱能信号传导是胶质细胞迁移所必需的。
