Embryonic Methamphetamine Exposure Inhibits Methamphetamine Cue Conditioning and Reduces Dopamine Concentrations in Adult N2 Caenorhabditis elegans.
Embryonic Methamphetamine Exposure Inhibits Methamphetamine Cue Conditioning and Reduces Dopamine Concentrations in Adult N2 Caenorhabditis elegans.
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DOI：
10.1159/000445761
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发表时间：
2016
影响因子：
2.9
通讯作者：
Engleman EA
中科院分区：
文献类型：
--
作者：
Katner SN;Neal-Beliveau BS;Engleman EA
甲基苯丙胺（MAP）成瘾在当今社会相当普遍，每年导致数千人死亡并造成数十亿美元的损失。尽管有潜在的有害后果，很少有研究检查胚胎MAP暴露的长期影响。利用无脊椎线虫秀丽隐杆线虫（C. elegans）允许对由于早期发育药物暴露引起的行为和神经化学变化进行受控分析。本研究的目的是确定长期的行为和神经化学的影响，胚胎暴露于MAP在C。优美的此外，我们试图通过利用液体过滤（而不是琼脂）和更小的6孔测试板来改善我们的调节和测试程序，以增加通量。野生型N2 C. elegans胚胎暴露于50 μM MAP。使用经典条件反射，成人阶段C。在存在钠离子（Na+）或氯离子（Cl-）作为条件刺激（CS+/CS-）的情况下，将elegans条件化至MAP（17和500 μM）。调节后，通过将蠕虫置于6孔试验板中进行偏好试验，在每个孔的相对端点样CS+和CS-。通过计数CS+靶区中的蠕虫数量除以CS+和CS-靶区中的蠕虫总数来确定偏好指数（PI）。还进行了食物调节实验，以确定胚胎MAP暴露是否影响食物调节行为。在神经化学实验中，使用高效液相色谱法（HPLC）分析胚胎暴露于MAP的蠕虫的（多巴胺）DA含量。本文采用的液体过滤调节程序与使用6孔测试板相结合，显著减少了进行这些实验所需的时间，并最终增加了通量。MAP调节数据发现，将离子与17或500 μM的MAP配对，显著增加了未预先暴露于MAP的蠕虫对该离子（CS+）的偏好。然而，蠕虫胚胎暴露于MAP没有表现出显着的药物提示条件。不能MAP暴露蠕虫的条件MAP是不相关的赤字在食品调理，作为MAP暴露蠕虫表现出显着的线索偏好与食物。此外，我们的研究结果发现，胚胎MAP暴露降低了成年C。elegans，这可能是一个关键的机制，有助于胚胎MAP暴露的长期影响。胚胎期MAP暴露可能损害了C.然而，我们的食物调节数据表明，MAP暴露的动物可以形成线索和食物之间的关联。胚胎暴露于MAP期间DA水平的耗竭可能是成年期驱动这些过程的原因。
Methamphetamine (MAP) addiction is substantially prevalent in today's society, resulting in thousands of deaths and costing billions of dollars annually. Despite the potential deleterious consequences, few studies have examined the long-term effects of embryonic MAP exposure. Using the invertebrate nematode Caenorhabditis elegans (C. elegans) allows for a controlled analysis of behavioral and neurochemical changes due to early developmental drug exposure. The objective of the current studies was to determine the long-term behavioral and neurochemical effects of embryonic exposure to MAP in C. elegans. In addition, we sought to improve our conditioning and testing procedures by utilizing liquid filtration, as opposed to agar, and smaller, 6-well testing plates to increase throughput. Wild-type N2 C. elegans were embryonically exposed to 50 μM MAP. Using classical conditioning, adult-stage C. elegans were conditioned to MAP (17 and 500 μM) in the presence of either sodium ions (Na+) or chloride (Cl-) ions as conditioned stimuli (CS+/CS-). Following conditioning, a preference test was performed by placing worms in 6-well test plates spotted with the CS+ and CS- at opposite ends of each well. A preference index (PI) was determined by counting the number of worms in the CS+ target zone divided by the total number of worms in the CS+ and CS- target zones. A food conditioning experiment was also performed in order to determine if embryonic MAP exposure affected food conditioning behavior. For the neurochemical experiments, adult worms that were embryonically exposed to MAP were analyzed for (dopamine) DA content using high performance liquid chromatography (HPLC). The liquid filtration conditioning procedure employed here in combination with the use 6-well test plates significantly decreased the time required to perform these experiments and ultimately increased throughput. The MAP conditioning data found that pairing an ion with MAP at 17 or 500 μM significantly increased the preference for that ion (CS+) in worms that were not pre-exposed to MAP. However, worms embryonically exposed to MAP did not exhibit significant drug cue conditioning. The inability of MAP exposed worms to condition to MAP was not associated with deficits in food conditioning, as MAP exposed worms exhibited a significant cue preference associated with food. Furthermore, our results found that embryonic MAP exposure reduced DA levels in adult C. elegans, which could be a key mechanism contributing to the long-term effects of embryonic MAP exposure. It is possible that embryonic MAP exposure may be impairing the ability for C. elegans to learn associations between MAP and the CS+ or inhibiting the reinforcing properties of MAP, however, our food conditioning data suggest that MAP exposed animals can form associations between cues and food. The depletion of DA levels during embryonic exposure to MAP could be responsible for driving either of these processes during adulthood.