Geladopoulos T, Sakellaridis N, Vernadakis A
Neurochem Res. 1987 Mar;12(3):279-88. doi: 10.1007/BF00972138.
The developmental profiles of the binding of mu and delta opiate receptors agonists was investigated using the chick embryo brain. Binding of opioids was performed at embryonic days 5, 6, 15, 18, and 20 in the developing chick embryo brain. [3H]dihyromorphine was used as a mu ligand and with 5 X 10(-7) M levorphanol for non-specific binding, and 3H-enkephalin was used as a delta with 5 X 10(-7) M (D-Ser-Gly-Phe-Leu-Thr)-enkephalin for non-specific binding. Crude membranes were prepared from whole brain at days 5, 6 and cerebral hemispheres at days 15, 18, and 20 of embryonic age. Both mu and delta opiate receptors were present during early embryogenesis and as early as day 5. Analysis of binding sites revealed high and low affinity mu sites during early embryogenesis but only one delta site. By 18 days of embryonic age, only one mu site remained. This developmental change is interpreted as a transitory state of the receptor to the adult mu pattern. The presence of only one delta site is constant throughout embryonic age; it is high during early embryogenesis reaching a lower level by 18 days. The presence of a dual binding site pattern for the mu receptor in early embryogenesis is implicated to have a functional significance in the pluripotential role of the endogenous opioids in early development.
利用鸡胚脑研究了μ和δ阿片受体激动剂结合的发育情况。在发育中的鸡胚脑的胚胎第5、6、15、18和20天进行阿片类药物的结合实验。[3H]二氢吗啡用作μ配体，5×10(-7)M左啡诺用于非特异性结合，3H-脑啡肽用作δ配体，5×10(-7)M(D-丝氨酸-甘氨酸-苯丙氨酸-亮氨酸-苏氨酸)-脑啡肽用于非特异性结合。在胚胎第5、6天从全脑制备粗制膜，在胚胎第15、18和20天从大脑半球制备粗制膜。μ和δ阿片受体在胚胎早期发育阶段就已存在，最早在第5天就有。结合位点分析显示，在胚胎早期发育阶段存在高亲和力和低亲和力的μ位点，但只有一个δ位点。到胚胎第18天，仅剩下一个μ位点。这种发育变化被解释为受体向成年μ模式的过渡状态。整个胚胎发育阶段δ位点只有一个，保持恒定；在胚胎早期发育阶段较高，到第18天降至较低水平。胚胎早期发育阶段μ受体存在双结合位点模式，这被认为对内源性阿片类物质在早期发育中的多能作用具有功能意义。
