Epple Gisela, Bryant Bruce P, Mezine Igor, Lewis Stanley
Monell Chemical Senses Center, 3500 Market St, Philadelphia, PA 19104, USA.
Pest Manag Sci. 2004 Jul;60(7):624-30. doi: 10.1002/ps.886.
Total extract from the fruit of Szechuan pepper (Zanthoxylum piperitum DC), the volatile components of the extract and a non-volatile fraction containing alkylamides (NVA fraction) are feeding deterrents for rats. The present study investigated the effectiveness of these natural repellents in prairie voles (Microtus ochrogaster Wagner). Two-choice feeding trials were conducted during which food-deprived voles were offered choices between oat-bran wafers. In Experiment 1, 10 voles were given three sets of feeding trials, each 2 h long. Baseline consumption was established during the first set of two trials by offering a choice between two oat-bran wafers dipped in ethanol, the control solvent. During the second set of two trials the voles were given a choice between an oat-bran wafer dipped in ethanol and a wafer dipped in Zanthoxylum extract. During the third set the voles were given a choice between a wafer served on top of a screened dish containing a sample of ethanol and a wafer served on top of a dish containing a sample of extract. In this manner the voles were exposed to volatile compounds emanating from the extract but could not contact it. Wafers dipped in extract were almost completely avoided. The volatile components of extract also significantly reduced food intake. In Experiment 2, habituation to the volatile constituents of extract was examined in 16 Zanthoxylum-naïve voles. Baseline consumption was established by offering two wafers served on top of screened dishes containing ethanol. This was followed by twelve tests during which a choice between a wafer served above a sample of ethanol and a wafer served above a sample of extract was given. The voles failed to habituate to the volatile components of extract, consistently consuming less of the wafers served above extract. In Experiment 3 a dose-response curve to Zanthoxylum extract was established, using 12 stimulus-naive voles. After baseline consumption was established, the animals were given two tests each, presenting a choice between a control wafer and a wafer dipped in a dilution of extract (0.001-100 g liter(-1)). Only concentrations of 10 and 100 g liter(-1) reduced food intake. In Experiment 4 the effects of the non-volatile fraction of extract were compared to those of whole extract. Vegetable oil was used as solvent. Eight stimulus-naïve voles were given two tests with a choice between an oil-dipped and an extract-dipped wafer. A second group of eight voles received two tests with a choice between an oil-dipped and NVA-dipped wafer. Extract-dipped wafers were avoided, but the NVA fraction had no effect on food consumption.
花椒（Zanthoxylum piperitum DC）果实的总提取物、提取物的挥发性成分以及含有烷基酰胺的非挥发性部分（NVA部分）对大鼠具有摄食抑制作用。本研究调查了这些天然驱避剂对草原田鼠（Microtus ochrogaster Wagner）的有效性。进行了双选摄食试验，在此期间，让饥饿的田鼠在燕麦麸薄饼之间进行选择。在实验1中，10只田鼠进行了三组摄食试验，每组试验持续2小时。在第一组的两次试验中，通过提供两片浸有乙醇（对照溶剂）的燕麦麸薄饼来确定基线摄入量。在第二组的两次试验中，让田鼠在一片浸有乙醇的燕麦麸薄饼和一片浸有花椒提取物的薄饼之间进行选择。在第三组试验中，让田鼠在放在装有乙醇样品的筛盘上的薄饼和放在装有提取物样品的盘子上的薄饼之间进行选择。通过这种方式，田鼠接触到了提取物释放出的挥发性化合物，但无法接触到提取物本身。浸有提取物的薄饼几乎完全被避开。提取物的挥发性成分也显著减少了食物摄入量。在实验2中，对16只从未接触过花椒的田鼠进行了对提取物挥发性成分的适应性研究。通过提供两片放在装有乙醇的筛盘上的薄饼来确定基线摄入量。随后进行了12次试验，在此期间，让田鼠在放在乙醇样品上方的薄饼和放在提取物样品上方的薄饼之间进行选择。田鼠未能适应提取物的挥发性成分，始终较少食用放在提取物上方的薄饼。在实验3中，使用12只从未接触过刺激物的田鼠建立了对花椒提取物的剂量反应曲线。在确定基线摄入量后，对动物进行了两次试验，每次试验都提供在对照薄饼和浸有提取物稀释液（0.001 - 100 g·L⁻¹）的薄饼之间进行选择。只有浓度为10和100 g·L⁻¹的提取物减少了食物摄入量。在实验4中，将提取物的非挥发性部分的效果与整个提取物的效果进行了比较。使用植物油作为溶剂。8只从未接触过刺激物的田鼠进行了两次试验，在浸有油的薄饼和浸有提取物的薄饼之间进行选择。第二组8只田鼠进行了两次试验，在浸有油的薄饼和浸有NVA的薄饼之间进行选择。浸有提取物的薄饼被避开，但NVA部分对食物消耗没有影响。
