Klaassen L W, Kammer A E
J Neurobiol. 1985 May;16(3):227-43. doi: 10.1002/neu.480160307.
The effect of octopamine on neuromuscular transmission was examined in developing and adult Manduca sexta. Intracellular recordings were made from the dorsal longitudinal muscle (DLM), superfused with solutions containing DL-octopamine or other amines. In untreated adult moths and pharate adults nearly ready to enclose (stage Day 19), stimulation of the motor nerve evokes a large excitatory junction potential (EJP), an active membrane response, and a twitch. In adults and Day 19 animals DL-octopamine (10(-7) to 10(-4)M) has no effect on the amplitude and rise-time of the electrical response in normal saline, but 10(-6) to 10(-4) M DL-octopamine increases the amplitude of the excitatory junction potential recorded in saline containing one-third the normal calcium concentration. Immature (Day 16) muscle, which normally produces only small EJPs following stimulation of its motor nerve, responds to 10(-6) to 10(-4) M DL-octopamine by an increase in the EJP above threshold for an active membrane response and a contraction. When the muscle has developed sufficiently to spike and contract in response to nerve stimulation in the absence of exogenous octopamine (Days 17 and 18), application of DL-octopamine increases the maximum rate at which the muscle contracts in response to each stimulus in a train (designated the maximum following frequency, MFF). The threshold dose for an effect on the MFF of Day 18 immature moths is less than 10(-10) M. At this stage 10(-8) M DL-octopamine increases the MFF four-fold. The effect on the MFF is dose-dependent over the range 10(-10) M to 10(-6) M. The biogenic amines DL-epinephrine, DL-norepinephrine, tyramine, DL-phenylethanolamine, 2-phenylethylamine, and dopamine, applied at concentrations of 10(-8) or 10(-4) M, do not change the MFF. Both DL-synephrine (10(-8) M) and serotonin (10(-7) M) mimic the action of 10(-10) M DL-octopamine on the MFF. The action of DL-octopamine (10(-7) M) is blocked by phentolamine (10(-4)M) but not by propranolol (10(-4)M). The octopamine content of hemolymph was determined with a radioenzymtic assay. The concentration of octopamine in the hemolymph increases 3.6-fold, from 5 X 10(-8) M on Day 18 (duration of adult development is 19 days) to 1.85 X 10(-7) M one day following eclosion.(ABSTRACT TRUNCATED AT 400 WORDS)
在发育中的和成年的烟草天蛾中研究了章鱼胺对神经肌肉传递的影响。从背纵肌（DLM）进行细胞内记录，背纵肌用含有DL - 章鱼胺或其他胺类的溶液进行灌流。在未处理的成年蛾和即将羽化的蛹（第19天阶段）中，刺激运动神经会引发一个大的兴奋性接头电位（EJP）、一个活跃的膜反应和一次抽搐。在成年蛾和第19天的动物中，DL - 章鱼胺（10⁻⁷至10⁻⁴M）在生理盐水中对电反应的幅度和上升时间没有影响，但10⁻⁶至10⁻⁴M的DL - 章鱼胺会增加在含有正常钙浓度三分之一的盐水中记录到的兴奋性接头电位的幅度。未成熟（第16天）的肌肉，在刺激其运动神经后通常只产生小的EJP，对10⁻⁶至10⁻⁴M的DL - 章鱼胺的反应是EJP增加到高于活跃膜反应和收缩阈值。当肌肉发育到在没有外源性章鱼胺的情况下对神经刺激能够产生动作电位和收缩时（第17天和第18天），施加DL - 章鱼胺会增加肌肉对一串刺激中每个刺激的最大收缩速率（称为最大跟随频率，MFF）。对第18天未成熟蛾的MFF产生影响的阈值剂量小于10⁻¹⁰M。在此阶段，10⁻⁸M的DL - 章鱼胺使MFF增加四倍。在10⁻¹⁰M至10⁻⁶M范围内，对MFF的影响呈剂量依赖性。以10⁻⁸或10⁻⁴M的浓度施加生物胺DL - 肾上腺素、DL - 去甲肾上腺素、酪胺、DL - 苯乙醇胺、2 - 苯乙胺和多巴胺，不会改变MFF。DL - 辛弗林（10⁻⁸M）和5 - 羟色胺（10⁻⁷M）都模拟10⁻¹⁰M的DL - 章鱼胺对MFF的作用。DL - 章鱼胺（10⁻⁷M）的作用被酚妥拉明（10⁻⁴M）阻断，但不被普萘洛尔（10⁻⁴M）阻断。用放射酶法测定血淋巴中的章鱼胺含量。血淋巴中章鱼胺的浓度增加3.6倍，从第18天（成年发育持续时间为19天）的5×10⁻⁸M增加到羽化后一天的1.85×10⁻⁷M。（摘要截短于400字）
