Laboratorio de Neurofarmacología, Centro de Investigación en Biotecnología, CEIB, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa 62209, Cuernavaca, Morelos, Mexico.
Centro de Investigaciones Químicas, IICBA, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Col. Chamilpa 62209, Cuernavaca, Morelos, Mexico.
Biomed Pharmacother. 2018 Jan;97:496-502. doi: 10.1016/j.biopha.2017.10.089. Epub 2017 Nov 6.
Ipomoea tyrianthina Lindley (syn. I. orizabensis Pelletan, Lebed. ex Steud., Convolvulaceae) is known as a purgative, but it has been also used in Mexican traditional medicine in the treatment of seizures and pain for their anticonvulsive, hypnotic and sedative properties. Some glycolipids isolated from this plant have shown significant effects on Central Nervous System, modifying inhibitory or excitatory processes. The mechanism for such activity it is not clear; studies with these metabolites have suggested that a pore-forming mechanism is involved in their activity. Therefore, the present work explores a possible not pore-forming mechanism related to the effect of four resin glycosides, Scammonin 1 (S-1), tyrianthin C (T-C), tyrianthin A (T-A) and tyrianthinic acid VI (TA-VI), isolated from Ipomoea tyrianthina root on GABAergic transmission system in cerebral cortex slices of mouse brain in an in vitro model. The results obtained show that all glycolipids tested evoked endogenous GABA release and increased its concentration within the incubation medium compared with controls; T-C demonstrated a dose-dependent effect. Sodium absence and guvacine presence did not affect significantly the activity of S-1 and T-C in contrast to T-A and TA-VI. S-1 and T-C effects were calcium-dependent, where GABA concentrations were considerably reduced. These results suggest that the increase of endogenous γ-aminobutyric acid (GABA) released evoked by these glycolipids is possibly done through a Na- and/or Ca-dependent mechanisms, discarding a pore-forming mechanism.
Ipomoea tyrianthina Lindley（同义词：I. orizabensis Pelletan、Lebed. ex Steud.、旋花科）被称为泻药，但它也被用于墨西哥传统医学中治疗癫痫发作和疼痛，因为它具有抗惊厥、催眠和镇静作用。从这种植物中分离出的一些糖脂对中枢神经系统具有显著的影响，可调节抑制或兴奋过程。其作用机制尚不清楚；对这些代谢物的研究表明，形成孔的机制可能与它们的活性有关。因此，本工作探索了一种可能与从 Ipomoea tyrianthina 根部分离得到的 4 种树脂糖苷 Scammonin 1（S-1）、tyrianthin C（T-C）、tyrianthin A（T-A）和 tyrianthinic acid VI（TA-VI）相关的非形成孔机制有关，研究它们对体外培养的小鼠大脑皮层切片中 GABA 能传递系统的影响。结果表明，所有测试的糖脂都能诱发内源性 GABA 释放，并使孵育介质中的 GABA 浓度与对照组相比增加；T-C 表现出剂量依赖性作用。与 T-A 和 TA-VI 相比，钠离子缺失和 guvacine 存在并没有显著影响 S-1 和 T-C 的活性。S-1 和 T-C 的作用依赖于钙，GABA 浓度显著降低。这些结果表明，这些糖脂引起的内源性 γ-氨基丁酸（GABA）释放的增加可能是通过 Na-和/或 Ca-依赖性机制实现的，排除了形成孔的机制。
