Boer G J, Kellerman A A, Baker R E, te Riele P, Feenstra M G, Botterblom M, Erdtsieck-Ernste B H
Graduate School Neurosciences Amsterdam, Netherlands Institute for Brain Research.
Neurochem Res. 1995 May;20(5):579-86. doi: 10.1007/BF01694539.
The presence and time-course of beta-adrenoceptor density in cultured explants of neocortex obtained from 6-day-old rat pups were investigated using a [125I]ICYP binding assay. A delayed, but more pronounced, increase in the receptor expression was observed as compared to the situation previously described in vivo. These changes only occurred for the beta 1-subtype of the receptor, whereas the beta 2-subtype binding remained constant up to 3 weeks in vitro. The delay of beta 1-adrenoceptor expression may be due to the incomplete presence of the proper maturational input, and the late enhancement of receptor expression to upregulation related to the absence in vitro of noradrenergic input. Decreased beta-adrenoceptor levels could be induced by chronic treatment of the beta-agonist isoproterenol (1 microM) introduced either for 3 or 13 days. Again, changes in density were found only for the beta 1-adrenoceptor binding sites. There is no reduction of receptor density following return to control conditions for 10 days after a 3-day treatment with isoproterenol, demonstrating the ability of this model to attain its final receptor density notwithstanding the developmental insult.
使用[125I]ICYP结合试验研究了从6日龄大鼠幼崽获得的新皮质培养外植体中β-肾上腺素能受体密度的存在情况和时间进程。与先前在体内描述的情况相比，观察到受体表达出现延迟但更为明显的增加。这些变化仅发生在受体的β1亚型中，而β2亚型结合在体外长达3周保持恒定。β1-肾上腺素能受体表达的延迟可能是由于适当成熟输入的不完全存在，以及受体表达后期增强至与体外去甲肾上腺素能输入缺失相关的上调。慢性给予β-激动剂异丙肾上腺素（1 microM）3天或13天可诱导β-肾上腺素能受体水平降低。同样，仅在β1-肾上腺素能受体结合位点发现密度变化。在用异丙肾上腺素处理3天后恢复对照条件10天，受体密度没有降低，这表明该模型尽管受到发育损伤仍能达到其最终受体密度。
