Enderlin V, Pallet V, Alfos S, Dargelos E, Jaffard R, Garcin H, Higueret P
Laboratoire de Nutrition, Université Bordeaux I, Talence, France.
Neurosci Lett. 1997 Jun 27;229(2):125-9. doi: 10.1016/s0304-3940(97)00424-2.
Ageing is accompanied by certain problems resulting from changes of hormonal status, in particular thyroid hormone (T3) status and vitamin A status. Since retinoic acid (RA), the active metabolite of vitamin A, and T3 play physiological roles in the adult brain, the effect of ageing on the amounts of mRNA for retinoic acid (RAR and RXR) and triiodothyronine (TR) nuclear receptors were studied. Also, the expression of RA and T3 target genes, tissue transglutaminase (tTG) and neurogranin (RC3), was measured in the whole brain and in the hippocampus of mice. Relative to young (3 months) mice, aged (22 months) mice exhibited lower amounts of RAR, RXR and TR mRNA concomitantly with a lower expression of tTG and RC3. RA administration to old mice (24 h before sacrifice) was able to restore the amount of mRNA of nuclear receptors and of RC3. It is hypothesized that a decrease in the cellular action of RA and T3 could play a role, via a decrease in the expression of RC3, in the alteration of synaptic plasticity occurring in aged mice.
衰老伴随着激素状态变化，尤其是甲状腺激素（T3）状态和维生素A状态变化而产生的某些问题。由于维生素A的活性代谢产物视黄酸（RA）和T3在成人大脑中发挥生理作用，因此研究了衰老对视黄酸（RAR和RXR）和三碘甲状腺原氨酸（TR）核受体mRNA含量的影响。此外，还在小鼠的全脑和海马体中测量了RA和T3靶基因、组织转谷氨酰胺酶（tTG）和神经颗粒素（RC3）的表达。相对于年轻（3个月）小鼠，老年（22个月）小鼠的RAR、RXR和TR mRNA含量较低，同时tTG和RC3的表达也较低。给老年小鼠（处死前24小时）注射RA能够恢复核受体和RC3的mRNA含量。据推测，RA和T3细胞作用的降低可能通过RC3表达的降低，在老年小鼠突触可塑性改变中发挥作用。
