Budnik V, Martin-Morris L, White K
J Neurosci. 1986 Dec;6(12):3682-91. doi: 10.1523/JNEUROSCI.06-12-03682.1986.
We have initiated a study of catecholamine-containing neurons in Drosophila melanogaster because of the potential, with this organism, to perturb catecholamine metabolism using genetic tools. The major objectives of this study were (1) to define the pattern of catecholamine-containing neurons and (2) to determine the effect of the absence of dopa decarboxylase (DDC) enzyme activity on the catecholamine-containing neurons. We chose to analyze the catecholamine-containing neurons in the ventral ganglion of the larval CNS. To define the catecholamine-containing neurons, CNSs were dissected and reacted with glyoxylic acid. The catecholamine histofluorescence (CF) neuronal pattern (normal-CF neurons) in the wild-type ventral ganglion is stereotypic. In the mutant ventral ganglia, in the absence of DDC enzyme activity, most normal-CF neurons still exhibit CF, probably indicating the presence of accumulated L-dopa. Interestingly, in the mutant CNSs, additional novel neuronal subsets also exhibit CF. Analysis of CNSs from early developmental stages revealed that the novel-CF neurons become fluorogenic earlier than the normal-CF neurons in the mutant CNS. To determine whether neuronal subsets, in addition to the normal-CF, neurons are able to sequester catecholamines, CNSs from wild-type larvae were incubated in exogenous catecholamine (L-dopa or dopamine). Incubations in L-dopa or dopamine revealed normally nonfluorogenic neurons that are able to take up the amine and become fluorogenic. Among the neurons able to sequester L-dopa or dopamine are subsets that are similar to the novel-CF neurons in the mutant CNS. This similarity is best characterized by a major novel-CF neuronal cluster in the subesophageal-thoracic region. These results suggest that in the absence of DDC activity, subsets of normally nonfluorogenic neurons capable of sequestering L-dopa or dopamine accumulate the fluorogenic catecholamine. Hypotheses that might explain the mode of accumulation of the catecholamine within the novel-CF neurons are considered.
由于利用该生物体通过遗传工具干扰儿茶酚胺代谢具有潜力，我们启动了一项对黑腹果蝇中含儿茶酚胺神经元的研究。本研究的主要目标是：（1）确定含儿茶酚胺神经元的模式；（2）确定多巴脱羧酶（DDC）酶活性缺失对含儿茶酚胺神经元的影响。我们选择分析幼虫中枢神经系统腹神经节中的含儿茶酚胺神经元。为了确定含儿茶酚胺神经元，解剖中枢神经系统并使其与乙醛酸反应。野生型腹神经节中的儿茶酚胺组织荧光（CF）神经元模式（正常CF神经元）是刻板的。在突变体腹神经节中，在缺乏DDC酶活性的情况下，大多数正常CF神经元仍表现出CF，这可能表明存在积累的左旋多巴。有趣的是，在突变体中枢神经系统中，另外一些新的神经元亚群也表现出CF。对早期发育阶段中枢神经系统的分析表明，在突变体中枢神经系统中，新CF神经元比正常CF神经元更早产生荧光。为了确定除正常CF神经元外的神经元亚群是否能够摄取儿茶酚胺，将野生型幼虫的中枢神经系统置于外源性儿茶酚胺（左旋多巴或多巴胺）中进行孵育。用左旋多巴或多巴胺孵育发现，正常情况下不产生荧光的神经元能够摄取胺并变得产生荧光。在能够摄取左旋多巴或多巴胺的神经元中，有一些亚群与突变体中枢神经系统中的新CF神经元相似。这种相似性最明显的特征是在咽下胸段区域有一个主要的新CF神经元簇。这些结果表明，在缺乏DDC活性的情况下，能够摄取左旋多巴或多巴胺的正常情况下不产生荧光的神经元亚群积累了产生荧光的儿茶酚胺。文中还考虑了可能解释儿茶酚胺在新CF神经元内积累方式的假说。
