Hirayama T, Ono H, Fukuda H
Department of Toxicology and Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
Brain Res. 1991 Jan 25;539(2):320-3. doi: 10.1016/0006-8993(91)91637-g.
The excitatory effects of adrenoceptor agonists on ventral horn cells were compared using an extracellular recording technique in spinal cord slices isolated from non-treated and 6-hydroxydopamine (6-OHDA)-treated rats (intracisternally 14 days previously). In spinal cord slices isolated from 6-OHDA-treated rats, the concentration-response curves for the alpha 1-adrenoceptor-mediated facilitatory effects produced by noradrenaline and phenylephrine but not those produced by methoxamine and isoproterenol were shifted to the left. 6-OHDA pretreatment decreased the level and uptake of noradrenaline and increased the number of [3H]prazosin binding sites in the spinal cord. These results suggest that in 6-OHDA-induced denervation, functional supersensitivity of the alpha 1-adrenergic system in the spinal ventral horn is due to absence of an uptake system, and not to postsynaptic change.
采用细胞外记录技术，比较了肾上腺素能受体激动剂对来自未处理大鼠和6-羟基多巴胺（6-OHDA）处理大鼠（14天前脑池内注射）的脊髓切片腹角细胞的兴奋作用。在从6-OHDA处理大鼠分离的脊髓切片中，去甲肾上腺素和苯肾上腺素产生的α1-肾上腺素能受体介导的促进作用的浓度-反应曲线向左移动，但甲氧明和异丙肾上腺素产生的曲线未发生移动。6-OHDA预处理降低了脊髓中去甲肾上腺素的水平和摄取，并增加了[3H]哌唑嗪结合位点的数量。这些结果表明，在6-OHDA诱导的去神经支配中，脊髓腹角α1-肾上腺素能系统的功能超敏性是由于摄取系统的缺失，而非突触后变化所致。
