Fitch G K, Kammer A E
J Neurobiol. 1986 Jul;17(4):303-16. doi: 10.1002/neu.480170405.
Intracellular recordings were made from the dorsal longitudinal muscle of Manduca sexta to determine the effects of development and octopamine on the excitatory junction potential (EJP) produced in response to electrical stimulation of the motor nerve. Observations were made on pharate moths during the last 3 days before eclosion and on adults. In saline, the highest values for EJP amplitude and maximum rate of rise and for resting membrane potential are reached on the nineteenth day of the pupal period, the day the animal ecloses; adult values are slightly lower. In animals of all ages tested, DL-octopamine (5 X 10(-6) M) increases EJP amplitude and maximum rate of rise. Increases in amplitude are greater in animals at stage day 17 and 18 than in animals at stage day 19 and adult. Octopamine has no effect on EJP rise time (onset to peak) or recovery time (peak of EJP to 70% recovery). Octopamine causes a hyperpolarization of about 6 mV. The results show that developmental changes in synapse properties are paralleled only in part by changes induced by octopamine. Both development and octopamine increase EJP amplitude and maximum rate of rise, and neither alter rise time. EJP recovery time changes with development but not in response to octopamine. Forskolin (10(-4) M) mimics the effects of octopamine on day 17 animals. EJP amplitude and maximum rate of rise are increased by forskolin, and rise time and recovery time are unaffected. Forskolin, like octopamine, causes a 6 mV hyperpolarization of the muscle fiber. These results suggest that octopaminergic modulation at the Manduca sexta dorsal longitudinal neuromuscular junction may be mediated by changes in intracellular levels of cyclic AMP.
从烟草天蛾的背纵肌进行细胞内记录，以确定发育和章鱼胺对运动神经电刺激产生的兴奋性接头电位（EJP）的影响。在羽化前最后3天的蛹蛾和成虫上进行观察。在生理盐水中，EJP振幅、最大上升速率和静息膜电位的最高值在蛹期的第19天达到，即动物羽化的当天；成虫的值略低。在所有测试年龄的动物中，DL-章鱼胺（5×10⁻⁶ M）增加EJP振幅和最大上升速率。第17天和18天阶段的动物振幅增加幅度大于第19天阶段的动物和成虫。章鱼胺对EJP上升时间（起始到峰值）或恢复时间（EJP峰值到70%恢复）没有影响。章鱼胺引起约6 mV的超极化。结果表明，突触特性的发育变化仅部分与章鱼胺诱导的变化平行。发育和章鱼胺都增加EJP振幅和最大上升速率，且两者都不改变上升时间。EJP恢复时间随发育而变化，但对章鱼胺无反应。福斯可林（10⁻⁴ M）模拟章鱼胺对第17天动物的影响。福斯可林增加EJP振幅和最大上升速率，且上升时间和恢复时间不受影响。福斯可林与章鱼胺一样，引起肌肉纤维6 mV的超极化。这些结果表明，烟草天蛾背纵神经肌肉接头处的章鱼胺能调制可能由细胞内环磷酸腺苷水平的变化介导。
