Eriksdotter Jönhagen M, Hoffer B, Luthman J
Department of Clinical Neuroscience and Family Medicine, Huddinge Hospital, Sweden.
Neurobiol Aging. 1995 Jul-Aug;16(4):633-8. doi: 10.1016/0197-4580(95)00053-h.
Age-related changes of hippocampal alpha 1- and alpha 2-adrenoceptors were investigated using intraocular hippocampal transplants combined with 3H-prazocin and 3H-para-aminoclonidine (3H-PAC) autoradiography. Young hippocampal grafts in young hosts and old grafts in old hosts innervated by noradrenergic sympathetic fibers were studied. In addition, young and old hippocampal grafts were examined following noradrenergic denervation by superior cervical ganglion removal. The 3H-PAC binding was significantly reduced in aged grafts as compared to young grafts whereas the 3H-prazocin binding did not change with age. After sympathetic denervation, both 3H-PAC and 3H-prazocin binding increased significantly in young grafts. In aged adrenergically denervated grafts, alpha 2-receptor binding was again significantly reduced whereas alpha 1-receptor binding was not significantly different from that in young denervated grafts. Taken together, these results indicate a selective age-related reduction in hippocampal postsynaptic alpha 2-receptors which is intrinsically determined.
利用眼内海马移植结合³H-哌唑嗪和³H-对氨基可乐定（³H-PAC）放射自显影技术，研究了海马α1和α2肾上腺素能受体的年龄相关变化。研究了由去甲肾上腺素能交感纤维支配的年轻宿主中的年轻海马移植物和老年宿主中的老年移植物。此外，在切除颈上神经节进行去甲肾上腺素能失神经支配后，对年轻和老年海马移植物进行了检查。与年轻移植物相比，老年移植物中³H-PAC结合显著减少，而³H-哌唑嗪结合不随年龄变化。去甲肾上腺素能失神经支配后，年轻移植物中³H-PAC和³H-哌唑嗪结合均显著增加。在老年去甲肾上腺素能失神经支配的移植物中，α2受体结合再次显著减少，而α1受体结合与年轻失神经支配移植物中的无显著差异。综上所述，这些结果表明海马突触后α2受体存在与年龄相关的选择性减少，这是内在决定的。
