Silveira V L, Limãos E A
Departamento de Fisiologia, Escola Paulista de Medicina, Sao Paulo, Brasil.
Agents Actions. 1992 Jul;36(3-4):294-9.
The participation of corticosteroids and alpha 2-macroglobulin (alpha 2-M) in counter-irritation (CI) induced by carrageenin was studied. We observed that CI could be produced when the second stimulus was done after 24 h, at which time glucocorticoids had already returned to their basal levels but alpha 2-M levels were maximum. When the level of alpha 2-M decreased (48 h) the counter-irritatory effect was not observed. As the synthesis of this protein is corticosteroid-dependent, we did not observe CI in adrenalectomized rats. However, when adrenalectomy was done 20 h after the first stimulus, allowing the synthesis of large amounts of alpha 2-M, the carrageenin stimulus again produced CI. Furthermore, adrenalectomized rats treated with aprotinin, a kallikrein inhibitor, after the first carrageenin stimulus, showed a reduction of the response to the second carrageenin stimulus. These observations demonstrated that corticosterone was not directly responsible for this inhibitory effect. Nevertheless, the anti-inflammatory factors involved in CI were, in fact, corticosteroid-dependent and alpha 2-M was probably one of the main factors.
研究了皮质类固醇和α2-巨球蛋白（α2-M）在角叉菜胶诱导的反刺激（CI）中的作用。我们观察到，当在24小时后进行第二次刺激时可产生CI，此时糖皮质激素已恢复到基础水平，但α2-M水平最高。当α2-M水平下降（48小时）时，未观察到反刺激作用。由于这种蛋白质的合成依赖于皮质类固醇，我们在肾上腺切除的大鼠中未观察到CI。然而，当在第一次刺激后20小时进行肾上腺切除术，从而允许合成大量α2-M时，角叉菜胶刺激再次产生CI。此外，在第一次角叉菜胶刺激后用抑肽酶（一种激肽释放酶抑制剂）处理的肾上腺切除大鼠，对第二次角叉菜胶刺激的反应有所降低。这些观察结果表明，皮质酮并非直接导致这种抑制作用。然而，参与CI的抗炎因子实际上依赖于皮质类固醇，α2-M可能是主要因素之一。
