Venugopalan C S, Flory W, Tucker T A, Hebert C D, Strain G M
Am J Vet Res. 1984 Apr;45(4):764-8.
An in vitro assessment based on tissue responsiveness to 2 agonists-histamine and carbachol-was made on smooth muscle activity in chickens experimentally poisoned with sesbania. Crude extracts of Sesbania drummondii were prepared and 2 dosage levels, 0.25% and 0.5% of body weight, were used. The birds were dosed orally with the extract for 3 consecutive days, and on the 4th day segments of ileum and lung were collected from each bird. The isometric contractions of each tissue, produced by the addition of histamine or carbachol in graded concentrations, were recorded. The cumulative concentration-effect curves for the tissues to the agonists were constructed and compared with respective control curves. The results indicated the responsiveness of the tissues in the treated groups was significantly decreased, compared with that of tissues in the controls. Responses of both intestinal and parenchymal strips in the chickens given the higher dosage (0.5%) were decreased significantly, whereas in those given the smaller dosage (0.25%), only parenchyma had a significant response. This indicates that the activity of smooth muscles in general was depressed by sesbania. The effect was more evident in the lung than in the intestine. Therefore, an active principle in the extract which affects smooth muscle, rather than causing direct irritation, may exist. This assessment of smooth muscle activity is sensitive and was effective in detecting changes in tissues from sesbania-treated birds which had not shown any clinical signs. The results also support the possibility that smooth muscle involvement could be a primary cause of toxicity in sesbania poisoning.
基于组织对组胺和卡巴胆碱这两种激动剂的反应性，对实验性中毒的鸡的平滑肌活性进行了体外评估。制备了德拉蒙德田菁的粗提物，并使用了0.25%和0.5%体重这两个剂量水平。给鸡连续3天口服提取物，在第4天从每只鸡收集回肠和肺的片段。记录通过添加不同浓度的组胺或卡巴胆碱所产生的各组织的等长收缩。构建各组织对激动剂的累积浓度-效应曲线，并与各自的对照曲线进行比较。结果表明，与对照组的组织相比，处理组的组织反应性显著降低。给予较高剂量（0.5%）的鸡的肠条和实质条的反应均显著降低，而给予较小剂量（0.25%）的鸡中，只有实质条有显著反应。这表明田菁总体上抑制了平滑肌的活性。这种作用在肺中比在肠道中更明显。因此，提取物中可能存在一种影响平滑肌而非引起直接刺激的活性成分。这种对平滑肌活性的评估是敏感的，并且有效地检测到了来自经田菁处理但未表现出任何临床症状的鸡的组织变化。结果还支持平滑肌受累可能是田菁中毒毒性的主要原因这一可能性。
