Markstein R, Wagner H
Gerontology. 1978;24 Suppl 1:94-105. doi: 10.1159/000212303.
In slices of rat cerebral cortex, cyclic-AMP formation is stimulated in response to added noradrenaline (NA), isoproterenol (ISP) or adenosine. The effect of ISP could be antagonized only by the selective beta-adrenoceptor-blocking agent pindolol, whereas the stimulating effect of NA could be antagonized by both alpha- and beta-adrenoceptor-blocking agents. Dihydroergotoxine (DHET) at low concentrations (10(-8)M) antagonized the stimulating effect of NA but not of ISP or adenosine, suggesting that this substance has a high affinity for central alpha-adrenoceptors. We could also show that DHET is accumulated in rat cerebral cortex after repeated oral application. In slices of cortex obtained from rats after treatment with DHET for 3 and 6 weeks, but not after 1 week, NA had a significant lower effect on cyclic-AMP formation than in slices from corresponding controls.
在大鼠大脑皮层切片中，添加去甲肾上腺素（NA）、异丙肾上腺素（ISP）或腺苷会刺激环磷酸腺苷（cyclic-AMP）的生成。ISP的作用仅能被选择性β-肾上腺素能受体阻滞剂吲哚洛尔拮抗，而NA的刺激作用可被α-和β-肾上腺素能受体阻滞剂同时拮抗。低浓度（10⁻⁸M）的双氢麦角毒碱（DHET）拮抗NA的刺激作用，但不拮抗ISP或腺苷的刺激作用，这表明该物质对中枢α-肾上腺素能受体具有高亲和力。我们还能证明，反复口服给药后，DHET会在大鼠大脑皮层中蓄积。在用DHET处理3周和6周但不是1周后的大鼠获得的皮层切片中，NA对环磷酸腺苷生成的影响比相应对照组切片中的显著更低。
